UNITED STATES DEPARTMENT OF THE INTERIOR, OscAR L. Chapman, Secretary
FISH AND WILDLIFE SERVICE, Albert M. Day, Director

AN ANNOTATED BIBLIOGRAPHY ON THE
BIOLOGY OF PACIFIC TUNAS

By Bell M. Shimada

FISHERY BULLETIN 58

From Fishery Bulletin of the Fish and Wildlife Service

VOLUME 52

UNITED STATES GOVERNMENT PRINTING OFFICE - WASHINGTON : 1951

For sale by the Superintendent of Documents, U. S. Government Printing Office, Washington 25, D. C.

Price 30 cents

CONTENTS

Page

Introduction 1

Annotated bibliography 3

Abbreviations used 25

Index by subjects 28

7^^-c':o

AN ANNOTATED BIBLIOGRAPHY ON THE BIOLOGY OF PACIFIC TUNAS

By Bell M. Shimada, Fishery Research Biologist

Studies were begun in 1948 by the Pacific
Oceanic Fishery Investigations of the U. S. Fish
and Wildlife Service to gather fundamental data
on the life histories, ecologj', and behavior of the
various species of Pacific tunas. Early in the
planning of the research program conducted from
the Hawaiian Islands, it was recognized that re-
view ajid systematic compilation of the literature
on these subjects were essential to the effective
guidance of the projected research. The principal
reference work available was the bibliography of
the tunas prepared some '20 years ago by Genevieve
Corwin (see Corwin 1930, in the Bibliogi-aphy,
p. 5). To meet the needs of the workers in the
Investigations, and to assist tuna researchers in
general, the preparation of this bibliography was
undertaken.

The bibliography deals chiefly with the black
skipjacks or little tunnies {Euthynnua aUefteratufi,
E. Uneatus, and E. yaito) , the oceanic or common
skipjack {Katsuwonus pelamis), the albacore
{Thvnmbs genno), the bluefin or black tunas
{ThimnuK viaccoyi^ T. oiicntalis, and T. tJiyn-
nus), the big-eyed tunas (Parathunnus meiachi
and P. ,siii), the yellowfin tuna {Neothunnus
jnacroptei'us), and the frigate mackerels of the
genus Auxis. Synonymous and related species
reported from the Pacific Ocean are included.
Waters contiguous to the Indo-Australian Archi-
pelago have been considei-ed as a part of the Pa-
cific Ocean proper, inasmuch as many of the
important studies of tuna sjjecies occurring in the
Pacific Ocean were based on data gathered in that
region.

In the review of the literature, some preliminary
work was done at Stanford University, Palo Alto,
and at the California Academy of Sciences, San
Francisco, California. The libraries of the Beniice
Pauahi Bishop Museum, the University of Hawaii,
and the Territoi-ial Board of Agriculture and For-
estry in Honolulu, and private collections of staff
members of the Investigations were particularly

productive of material. The Japanese references
were gathered by a reconnaissance team in Japan
from November 1948 to July 1949 investigating
the results of Japanese tuna research. Search of
private and public libraries in and about Tokyo
supplied much material that has not hitherto been
generally available outside Japan. Some refer-
ences found in Corwin's bibliography could not be
examined at first hand: these are included here,
as given hy Corwin, with a notation to show their
source.

The general style used by Corwin has been fol-
lowed in cataloging and annotating the material.
The arrangement of the references is by authors
listed alphabetically. Entry is made only under
the senior author's name if there is more than one
author; the abbreviation "et al." is used with the
senior author's name to show collaboration of more
than three authors. Each authors works are
listed chronologically by year of publication, and
those published in the same year are given in
alphabetical sequence. Generally, pagination is
given only for the parts of the publication falling
within the scope of the bibliography.

Appropriate notations in the bibliography dis-
tinguish those papers published only in Japanese,
those published in Japan but written in English,
and those jjublished in Japanese with an English
abstract. Translations were made of Japanese
titles when English equivalents were not given.

Brief annotations of the publications are in-
cluded except for those that could not be consulted
and for those whose titles give a clear indication
of the contents. The .scientific nomenclature used
by each author is followed in the annotations;
appropriate cross references to synonymous names
regarded as having priority appear in the Index.
Where both vernacular and scientific names of the
tuna were given, the scientific nomenclature is
retained.

The preparation of the Index presented consid-
erable difficulty owing to the confused state of the

FISHERY BULLETIN OF THE FISH AKD WILDLIFE SERVICE

taxonomy of the various species of tuna. As the
relationsliips of the tuna species of the Pacific, and
for that matter the world in general, have not been
clearly defined, specific names of questionable
validity have been arbitrarily indexed as separate
entries. For example, Neothunnus itosibi is re-
garded by some workers as a form distinct from
Neothunnus 7nacropterus, while others consider
the two to be synonymous. References to Neo-
thunnus ifosihi and Neothunnus jnacropte/iis,
therefore, have been treated separately. Syno-
nyms which are generally accepted as applying to
one given species, such as Euthynnus pelamis for
Katsuioonus pelamis, have been indexed under the
name which is believed to have priority, with
appropriate cross reference under the synonymous
name. The same procedure was used in indexing
names which differ slightly in spelling. Again,
it should be pointed out that the indexing of these
scientific names is to a large degree arbitrary, and
is not an attempt to clarify the systematics of the
tunas.

A list of abbreviations of the various publica-
tions cited and of the English translations of titles
of Japanese periodicals as used in the bibliography
is included.

Acknowledgment is made of the valuable assist-
ance and advice given the author by various indi-
viduals and organizations. Especially is credit
due the Fisheries Division, Natural Resources
Section, General Headquarters, Supreme Com-
mander for the Allied Powers, under W. C. Her-
rington, Drs. K. Kuronuma and Y. Hiyama, and
other Japanese scientists, and Dr. J. G. F. Harden-
burg of Batavia, Java, for their generous cooper-
ation. The author is also indebted to the library
staffs of Stanford University, the California
Academy of Sciences, University of Hawaii, and
the Bernice Pauahi Bishop Museum, and to Ver-
non Brock of the Division of Fish and Game,
Board of Agriculture and Forestry, Territory of
Hawaii, and staff members of the Pacific Oceanic
Fishery Investigations, who contributed mate-
rially to the preparation of this bibliography.

ANNOTATED BIBLIOGRAPHY

Explanation of symbols

[C] = references listed by Corwin (see Corwin 1930, p. 5) that could not be verified.

[J] —published in Japanese only.
[JE] = published in Japan but written in English.
[ Je] = written in Japanese with English abstract.

[P] = accession to the library of the Pacific Oceanic Fishery Investigations.

[For an explanation of the abbreviation see Itst, p. 25]

Abe, Tokihaku.
1939. A list of the fishes of the Palao Islands. Palao
Trop. Biol. Sta. Studies, No. 4, p. .jGT. [JE] [P]
Ocrmo macroplcrus, Kafstiiconus pelamys, Thuimus
thynnics: recorded; distribution.

AlKAWA, HiROAKI.

193.3. Fisliery conditions on the Pacific Coast for skip-
jack, tuna, and sauries. Proc. Sci. Fish. Assoc., vol.

5, No. 4, pp. 3.J4-369. [J] [P]

Alhacore, big-eyed tuna, black tuna, skipjack, yel-
lowfin tuna : fishing conditions correlated with sur-
face water temperature.

1937. Notes on the shoal of bonito along the Pacific
Coast of Japan. Bull. Japanese Soc. Sci. Fish., vol.

6, No. 1, pp. 13-21. [Je] [P]

Age analysis and size composition of skipjack
catches; stock and population relationships; use
of condition factor in separating migratory and
nonmigratory fish.
AiKAWA, Hlkoaki, and Masao Kato.

1938. Age determination of fish. I. BuU. Japanese Soc.
Sci. Fish., vol. 7, No. 2, pp. 79-88. [Je] [P]

Germo genno, Katsinconus vagans, Neothunnus
macroptenis, Tliunnus oricnfalis: age analysis using
vertebrae ; age composition of commercial catch ;
calculated length and weight groups ; body condi-
tion; growth rate; morpliometric data.
Anonymous.

1938. Status of the investigation of tuna longline fish-
ing grounds in the South China Sea. Formosa Fish.
Mag., No. 279, pp. 10-19. [J]

Alhacore, yellowfin tuna : body temperatures ; dis-
tribution ; length-weight data ; sexual maturity ;
stomach contents ; figured.

1939. Marked fish. Semi-Ann. Rpt. Oceanogr. Invest.,
No. &5, p. 137. [J]

Skipjack : Japan ; release records of tagged fish.
1941. Pacific skipjack indigenous to Sulu Sea. South
Sea Fish., vol. 7, No. 5, p. 5.5. [J] [P]
Distributional note.
-VSANO, N.\gao.

1939. Food of the alhacore, Germo germo (LacSpMe).
South Sea Fish. News, vol. 3, No. 7, pp. 10-11. [J] [P]
South Seas; stomach contents; AuxU sp. recorded
as food.

Ban, Yoshinori.
1941. Search for southern tuna fishing grounds. South
Sea Fish., vol. 7, No. 9, pp. 10-21. [J] [P]

Yellowfin tuna; South Seas; fishing conditions
correlated with oceanography ; stomach contents :
age analysis ; sexual maturity.
Barnhart, Percy.

1936. Marine fishes of Southern California. Univ. Cali-
fornia Press, Berkeley, pp. 36-37.

Auxis thazard, Katstnrotiiis pelamis, Germo ala-
liinga, Neothuniuis macroptcrits, Thiinnus thynnus:
description ; distribution ; English common names ;
figures.
Bennett, Fbedebick Debell.

1840. Narrative of a whaling voyage around the globe,
from the year 1833 to 1S36. Vol. 2, pp. 278-282.
London.

Scomber germo: description ; anatomy of reproduc-
tive system; food; enemies. Scomber pelamys:
description ; parasites.
Berg, Leo S.

1947. Classification of fishes both recent and fossil.
J. W. Edwards Co., Ann Arbor, pp. 491-492.

Anatomy and classification of Thunniformes
(Plecostei).
Bleekeb, Pieter.

1844. Bijdragen tot de geiieeskundige topographic van
Batavia. Generisch overzicht der fauna. Nat.
Geneesk. Arch. Neerland's Indie, vol. 1, p. 5.53.

Tliynnus: recorded.

1845. Bijdragen tot de geneeskundige topographic van
Batavia. Generisch overzicht der Fauna. Nat.
Geneesk. Arch. Neerland's Indie, vol. 2, p. 516.

Aiixis taso: recorded.
1850. Bijdrage tot de kennis der ichthyologische fauna
van Midden-en Oost-Java, met besehrijving van eenige
nieuwe species. Verb. Batavia Genoot. Kunst.
Wetens., vol. 23, p. 8.

Attxis taso: recorded.
1852. Bijdrage tot de kennis der makreelachtige vlsschen
van den Soenda-Moluksdien Archipel. Verb. Batavia
Genoot. Kunst. Wetens., vol. 24, pp. 36-37, 89.

Thynnus macroptenis, T. thunnina, and T. tonggol:

recorded from Dutch East Indies ; description and

synonymy of T. tonggol.

3

FISHEKT BULLErmsr OF THE> FISH AND "WILDLIFE SERVICE

Bleekeb, Pietek — Continued
ISd-t. Faunae ichthyologicae japonicae sjjecies novae.
Nat. Tijdschr. Nederlandsch-Indie, vol. 6, pp. 408-409.
Aiixis tapeinosoma : recorded and described.

1855. Vijfde bijdrage tot de kennis der ichthyologische
fauna van Ternate. Nat. Tijd.schr. Nederlandsch-
Indle, vol. 8, pp. 301-302.

Aiixis thyniiokles: recorded; description; compared
with A. tapeinosoma, A. taso, and A. vulgaris.

1856. Beschrijvingen van nieuwe en weinig bekende
vischsoorten van Amboina, versameld op eene reis
door den Molukschen Arcbipel, gedaan in bet gevolg
van den Gouverneur-Generaal Duyuiaer van Tvrist in
September en October 18.55. Act. Soc. Sci. Indo-
Neerlandicae, vol. 1, pp. 41-42.

Thyniuis prlnmys: recorded; description: syn-
onymy.
1S57. Nieuwe nalezingen op de ichthyologle van Japan.
Verb. Batavia Genoot. Kunst. Wetens., vol. 26, p. 98.

Auxis taiieinosoma: recorded.
1860a. Achtste bijdrage tot de kennis der vischfauna
van Sumatra. Vis.sehen van Benkoelen, Priaman,
Tandjong, Palembang, en Djambi. Act. Soc. Sci. Indo-
Neerlandicae, vol. 8, p. 29.

Thimnus pelamys, T. thunnina: recorded from the

Dutch East Indies.
ISGOb. Dertiende bijdrage tot de kennis der vischfauna
van Celebes. Visschen van Bonthain, Badjoa, Sindjal,
Lagoesi en Pompenoea. Act. Soc. Sci. Indo-Neer-
landicae, vol. 8, p. 38. [C]

Thnnmts tliunnina: recorded from Dutch East

Indies.
1861a. lets over de vischfauna van bet eiland Pinang.
Versl. Akad. Amsterdam, vol. 12, p. 74.

Thynnus a /finis: recorded from Dutch East Indies.
ISClb. Mededeeling omtrent visch.soorten, nieuw voor de
kennis der fauna van Singapoera. Versl. Akad. Am-
sterdam, vol. 12, p. 52. [C]

Thynnus tliunnina. T. totif/f/ol: recorded from

Singapore.

1862. Sixi&me m^moire sur la faune ichthyulogique de
rile Batjan. Versl. Akad. Amsterdam, vol. 14, p. 109.

Pelamys macroptenis, P. pelamys. Thynnus tliun-
nina: recorded from Dutch East Indies.

1863. Onzieme notice sur la fauna ichtbyologique de
I'ile de Ternate. Nederlandsch Tijdschr. Dierk., vol.
1, p. 235.

Auxis thynnoides : recorded.
1865a. :finum6ration des esp^ces de poissons actuelle-
ment connues de I'ile d'Amboine. Nederlandsch
Tijdschr. Dierk., vol. 2, p. 285.
Auxis thynnoides, Pelamys marropterus. P. pelamys,
P. tliunnina: recorded.
1865b. Sixieme notice sur la faune ichtbyologique de
Slam. Nederlandsch Tijdschr. Dierk., vol. 2, p. 173.
[C]
Thynnus thiinnina: recorded.
1878. Quatrifeme memoire sur la fauna ichtbyologique
de la Nouvelle-Guinfe. Arch. N^erlandaises Sci. Nat.,
vol. 13, p. 50.

Auxis taso: recorded.

Bleeker. Pieter — Continued

1870. Enumeration des especes de poissons actuelle-
ment connvies du Japon et description de trois especes
Inddites. Versl. Akad. Amsterdam, vol. 18, p. 15. [C]
Pelamys sihi Blkr. and Thynnus sibi Schl. com-
pared.
Boeseman, M.
1947. Revision of the fishes collected by Burger and von
Siebold in Japan. Zool. Meded., vol. 28, pp. 91-94.
Thynnus macroptcrus, T. orientalis, T. pelamys, T.
sibi, T. thunina: description; synonymy.

BONHAM, KELSHAW.

1946. Measurements of some pelagic commercial fishes
of Hawaii. Copeia, No. 2, pp. 81-84.

Katsuwonus pelamis: length-weight data and re-
lationship; length frequencies of Neothunnus mac-
ropterus; lengths of Euthynnus yaitn.
Brock, Vernon E.

1938. A new tuna record from Washington. Copeia,
No. 2, p. 98.

Thunnus thynnus: recorded.

1939. Occurrence of albacore, Oermo alalvnga, in mid-
Pacific. Copeia, No. 1, p. 47.

1943. Contribution to the biology of the albacore
(Oermo alalunga) of the Oregon coast and other
parts of the North Pacific. Stanford Ichth. Bull., vol.
2, No. 6, pp. 199-248.

Age and size composition; growth; spawning; sex

ratio; length-frequency data; population analysis.

1949. A preliminary reiiort on Paratliii units sibi in

Hawaiian waters and a key to the tunas and tuna-like

fi.shes of Hawaii. Pacific Sci., vol. 3, No. 3, pp. 271-

277.

P. sibi: description ; morphometric data ; feeding
habits. Auxis thazard, Euthynnus yaito, Qeinio
alaliiniia. Katsuwonus pelamis, Kishinoella rara,
Neothunnus macroptcrus, Parathunnus sibi, Thun-
nus orientalis, T. thynnus: key.
Cantor, Theodore.

1850. Catalogue of Malayan fishes. Jour. Asiatic Soc.
Bengal, vol. IS, pt. 2, pp. lOSS-1090.

Thynnus affinis: description; distribution; com-
pared with T. pelamys.
Castelnau, Count P. de.

1872. Contribution to the ichthyology of Australia.
Proc. Zool. Acclim. Soc. Victoria, vol. 1, pp. 104-105.
Thunnus macroyii: description.
Chabanaud, Paul M.

1926. Inventaire de la faune ichtyologique de I'lndo-
chine. Note Serv. Oceanogr. Pech. Indochine, No. 1,
p. 22.

thunnus thiinnina: listed.
Chapman, Wilbert M.

1946. Observations on tuna-like fishes in the tropical
Pacific. California Fish and Game, vol. 32, No. 4, pp.
165-170.

Euthynnus alletteratus, Katsuwonus pelamis, Neo-
thunnus macroptcrus: recorded; food of N. macrop-
tcrus noted.

BIBLIOGRAPHY ON PACIFIC TtJNAS

Che\'et, Pierke.
l!)32a. Inventaire de la fauna ichtyologique de I'lndo-
chine. Deuxi&me liste. Note Serv. Oceanogr. POch.
Indochine, No. 19, p. 26.
Euthynnus yaito: listed.
1932b. Poi.ssons des canipagnes du "de LanessMii"' (192.')-
1929). Trav. lust. Oceanogr. Indochine, 4'' Mem.,
pp. 11,'5-11,5.

Euthynnus i/aito: synonymy: distribution; descrip-
tion; Indo-Chinese common names; figure of speci-
men and scales.
1934. Revision synonymique de I'oeuvre ichtyologique
de G. Tirant. Note Serv. Oceanogr. Pech. Indochine,
No. 7, p. 46.

Thynnus thunnina listed by Tirant renamed
Euthynnus yaito.

Cnin.\ Prefecti RAi. Fisheries Experiment Station,
Katsuura Branch.

1930. Investigation of skip.lack fishing grounds. Prog.
Rpt. Chiba Pref. Fish. Expt. Sta. for 1934, pp. 1-12.

[J] [P]
Japan ; albacore and skipjaclc fishing conditions
correlated with water temperature.

1937. Investigation of skipjack fishing grounds. Prog.
Rpt. Chiba Pref. Fish. Expt. Sta., Katsuura Br. fr)r
193.^), pp. 1-9. [J] [P]

Japan ; skipjack catch correlated with water tem-
perature.

1938. The skipjack fishery. Prog. Rpt. Chiba Pref. Fish.
Expt. Sta., Katsuura Br. for 1936, pp. 2-11. [J] [P]

Japan ; skipjack catch correlated with water tem-
jierature.
1941. The skipjack fishery. Prog. Rpt. Chiba Pref. Fish.
Expt. Sta., Katsuura Br. for 193S. pp. 22-25. [J] [P]
Japan ; albacore and skipjack fl.shing conditions cor-
related with water temperature.

Cnti, Tuanting T.

1931. Index piscium sinensium. Biol. Bull. St. John's
Univ.,No. 1, pp. 107-108.

Auxis rorhei, Neothunnus nmcropterus: synonymy;
distribution.

Clark, Frances Naomi.

1929. A racial comparison of Californian, Hawaiian and
Japanese albacore (Oermo germo). California Fish
and Game, vol. 1.1, No. 4, pp. 3.51-.353. San Francisco.
Population studies based on comparisons of body
proportions, counts of raeristic characters, and sex-
ual maturity.

Clemens, W. A., and G. V. Wilby.

1946. Fishes of the Pacific Coa.st of Canada. Fi.sh. Res.
Bd. Canada, Bull. No. 4S, pp. 164-167.

Katsuwonus pdawis, Tliunnus alnlunga: descrip-
tion; distriliution ; food; records of capture in
Canadian Pacific waters ; figured.

Conn, John N.

1919. Scientific problems of the fisheries of the north
Pacific. Bull. Scripps Inst., No. 9, p. 4.5. [C]
Genno germo, Thunnus alalunga: migration.

Cooper, James Graham.

1863. On new genera and species of Californian fishes.
Proc. California Acad. Sci., vol. 3, pp. 7i>-77.
Orcynus pacificus: described as a new species; dis-
tribution ; figured.

CoRwiN, Genevieve A.

1930. A bibliography of the tunas. California Div. Fish
and Game, Fish Bull. No. 22, pp. 1-103.

("owAN, Ian M.

19.38. Some fish records from the coast ol' BritLsh Colum-
bia. Copeia, No. 2, p. 97.
Oermo nlalunga: recorded.

Craig, Joe Allen.

1929. List of common and scientific names of fishes.
California Div. Fish and Game. Fish I'.ull. No. 1."),
pp. 11-12.

Euthynnus pilumis, Oermo germo, yrollinnnus eiitn-
linae, Thunnus saliens: listed.

Cuvier, Georges, and Achiixes Valenciennes.

1831. Histoire naturelle des poissons. Vol. 8, pp. 85, 96,
107. Paris.

8eon)t)er taso, Thynmis paeificus. T. pelamys: de-
scription ; records of capture ; figure of T. pelamys.

DeJong, J. K.

1940. A preliminary investigation of the spawning hab-
its of some fishes of the Java Sea. Treubia. vol. 17.
No. 4, pp. 325-326.
Euthynnus aVitterntus: frequencies of egg diameter
measurements ; resorption of eggs noted.

Delsman, H. C.

1931. Fisli eggs and larvae from the Java Sea. Treubia.
vol. 13, Nos. .3-1, pp. 407-409.

Eggs and larvae believed to be those of Sconihrr
(Delsman, Treubia, vol. 8, Nos. 3-4, pp. 395-399)
reidentified as Thynmis thunnina.

Delsman, H. C, and J. G. F. Hardenburg.

1934. De Indische zeevischen en zeevisscherij. Blblio.
Nederlandsch Indische Nat. Ver., No. 6, pp. .330-343.
Euthjinnus alletteratiis, E. pelamys, Neothunnus
maeropterus, N. rarus: description; distribution:
key ; Malayan common names ; spawning of E. allet-
teratus and description of eggs and larvae; spawn-
ing of N. ranis and description of eggs; food of /.'.
pelamys; E. aHetteratus and .V. maeropterus figured.

Dill. D. B.

1921. .\ chemical study of certain Pacific coast fishes.
Jour. Biol. Chem., vol. 48, pp. 76, 81. [C]

Oermo alalunga, O. maeropterus, Thunnus thinniiis:
chemical analysis.

Domantay, Jose S.

1940. Tuna fishing in Southern Mindanao. Philippine
Jour. Sci.. vol. 73. No. 4. pp. 42.3-4.35.

Auxis thazard, Euthynnus yaito, Katsuwonus pela-
mis, Neothunnus itosihi. N. maeropterus, I'arathun-
nus sibi: distribution; figured.

6

FISHERY BULLEfTIN OF THE FISH AND WILDLIFE SERVICE

EcKLES, Howard H.

1949a. Fishery exploration in the Hawaiian Islands
(August to October 1948, liy the vessel Oregon of the
Pacific Exploration Company). Com. Fish. Rev., voL
11, No. 6, pp. 1-9.
Euthi/nnus yaito. Kaisuwonus pelamis, Neothunnus
macroiitenis : recorded; K. pelamis and N. macrop-
terus figured.
1949b. Observations on juvenile oceanic skipjack {Knt-
suiroiins pelamis) from Hawaiian waters and
sierra mackerel from the Eastern Pacific. U. S. Fish
and Wildlife Serv. Fish. Bull., vol. 51, No. 48, pp.
24.5-250.

Kntsiiwonus pelamis: anatomy, descriptions, fig-
ures, and records of capture of juveniles ; spawning ;
juveniles noted in stomachs of adults.

ElGENMANN, CaRL H.

1892. The fishes of San Diego, California. Proc. U. S.
Natl. Mus., vol. 15, No. 897, pp. 130, 147.

Gyninosnrda pelamys, Oreiinus alnlntuia: recorded;
seasonal occurrence of Euthynnus pelamis and O.
alalonga.

ElGENMANN, CARL H., and Rosa S. Eigenmann.

1890. Additions to the fauna of San Diego. Proc. Cali-
fornia Acad. Sci., 2 Ser., vol. 3, p. 8.

Euthynnus pelamys: recorded; description.

1891. A catalogue of the fishes of the Pacific coast of
America north of Cerros Island. Ann. New York
Acad. Sci., 1891-1892, vol. 6, p. 352.

Euthynnus pelamys, Germo alalongn: recorded.

E\'ERMANN, Barton W., and Alvin Seale.

1907. Fishes of the Philippine Islands. Bull. U. S. Bur.
Fish., vol. 26, p. 61.

Oymnosarda pelamis: listed; synonymy.

Fish, Marie Poland.

1948. Sonic fishes of the Pacific. Woods Hole Oceanogr.
Inst. Tech. Rpt., No. 2, pp. 87-91.

Aums thazard, Euthynnus, Oermo alalunga, Kat-
sttivonus pelamis, Ncothnnnns macropterus, Thun-
nns thj/nnns: distribution; English common names;
synonymy of K. pelamis, G. alalunga, T. thynnvs;
air bladders of G. alalunga, N. macropterus and T.
thynnus described; Japanese common names of
Euthynnus and T. thynnus; vertical distribution
of Parathnnnus mebachi noted.

Fitch, ,Iohn E.

1950. Notes on some Pacific fishes. California Fish and
Game, vol. 36, No. 2, p. 65.

Stomach contents of Neothunnus maeroptenis.

Food and Agriculture Organization, United Nations.

1949. Recommended scientific and common names of im-
portant food fishes. A. Scombriformes. Fish. Div.,
FAO, UN, 98 pp.

Auxis thasard, Euthynnus alletcratus. Genno ala-
lunga, Katsuwonus pelamis, Neothunnus macrop-
terus, Thunnus thynnus: distribution; synonymy;
world-wide common names and recommended
nomenclature.

Formosa Government-General Fisheries Experiment
Station.

1930. Northern oceanographic conditions and skipjack
fishing. Prog. Rpt. Formosa Govt. -Gen. Fish. Expt.
Sta. for 1928, Oceanogr. Sec, pp. 67-70. [J] [P]

Formosa; fishing conditions correlated with water
temperature, specific gravity, and currents.

1931. Northern oceanographic conditions and skipjack
fishing. Prog. Rpt. Formosa Govt.-Gen. Fish. Expt.
Sta. for 1929, Oceanogr. Sec, pp. 28-30. [J] [P]

Formosa ; fishing conditions correlated with water
temperature, specific gi-avity, and currents.

1932. Northern oceanographic conditions and skipjack
fishing. Prog. Rpt. Formosa Govt.-Gen. Fish. Expt.
Sta. for 1930, Oceanogr. Sec, pp. 10-11. [J] [P]

Formosa ; fishing conditions correlated with water
temperature, specific gravity, and currents.
1933a. Experimental fishing and investigation in south-
ern waters by the Shonan Maru. Prog. Rpt. Formosa
Govt.-Gen. Fish. Expt. Sta. for 1931, Fish. Sec, pp.
1-.50. [J] [P]

Yellowfln tuna : Indo-Pacific region ; length-weight
data ; fishing conditions in relation to oceanography
and weather ; catch per unit of effort ; distribution ;
stomach contents.
1933b. Oceanographic conditions and skipjack fishing in
northern Formosa. Prog. Rpt. Formosa Govt.-Gen.
Fish. Expt. Sta. for 1931, Oceanogr. Sec, pp. 13-15.
[J] [P]
Fishing conditions correlated with currents, surface
water temperature, and specific gravity.
1934. Oceanographic conditions and skipjack fishing in
northern Formosa. Prog. Rpt. Formosa Govt.-Gen.
Fish. Expt. Sta. for 1932, Oceanogr. Sec, pp. 10-12.
[J] [P]
Fishing conditions correlated with currents, surface
water temperature, and specific gravity.
Fowler, Henry W.

1904a. A collection of fishes from Sumatra. Jour. Acad.
Nat. Sci. Phila., 2 Ser., vol. 12, p. .506.
Germo germon: figured.
1904b. New, rare, or little-known Scombroids. Proc.
Acad. Nat. Sci. Phila., vol. 56, pp. 761-763.

Germo germon, Pelamys affine: description; syn-
onymy.
1923a. New or little-known Hawaiian fishes. Bernice P.
Bishop Mus. Occas. Papers, vol. 8, No. 7, pp. 376-392.
Germo macropterus, Thunnus thynnus: recorded.
192.3b. Records of West Coast fishes. Proc Acad. Nat.
Sci. Phila., vol. 75, p. 289.

Germo alalunga, Thunnus thynnus: recorded from
California.

1927. Fishes of the tropical central Pacific. Bull. Ber-
nice P. Bisliop Mus., No. 38, pp. 10-11.

Germo sibi: figured; description.

1928. The fishes of Oceania. Mem. Bernice P. Bishop
Mus., vol. 10. pp. 132-134.

Auxis thasiird, Euthynnus aUctteratus, E. pelamis,
Germo alhacorrs. G. alalunga, G. macropterus, G.
sibi, Thunnus thynnus: description; synonymy;
figures of E. alletteratus and G. sibi.

BIBLIOGRAPHY ON PACIFIC TUNAS

Fowler, Henry W. — Continued

1920. Notes on Japaiipse and Chinese fishes. Proc. Acad.
Nat. Sci. Pliila., vol. si, p. 590.

Gcimo sibi, Tliinnius thyntuis: seen in Japan.
1031. The fishes of Oceania - Supplement 1. Mem. Her-
nice P. Bishop Mns., vol. 11, No. 5, p. 325.

Eiithynnus allrttcratiis, E. pelamis, Onmo ahilunr/a,

O. nidcrontcnix, O. x'bi, Thunniis thiiiniiis: listed;

s.vnonymy of G. mncroptcrux.

1033. Description of a new lon.i,'-finned tmia {Semathun-

nus giiildi) from Tahiti. Proc. Acad. Nat. Sei. Phila.,

vol. ST), pp. 163-161.

De.scriptions of new genus Semafhiinnus and new
species, Scmathunnus guildi; Scmathunnux distin-
guished from Ncofhiinniis.

1934. The fishes of Oceania — Supplement 2. Mem. Ber-
niee P. Bishop Mus., vol. 11. No. 6, p. 400.

Eittliynnus peldinis, Semntlnitinus ijuildi, .S. itosili,
Thunnus orientalis, T. thynnus: listed; synonymy.

1935. The fishes of the George Vanderbilt South Pacific
Expedition, 1937. Acad. Nat. Sci. Phila., Monogr.
No. 2, pp. 31-33, 2.53, 277.

Aiixis thnxard, Eulhynuiis. Unentim. E. pclamis:
description; synonymy. A. thaznrd, Euihynnus
allctterafus, E. lineatus, E. pelamis, Qrrmo ala-
longa. Neofhunmis maoropterus. Pai-atlinnnus sibi,
Thunnus thynnus: recorded from Pacific.
1944. Results of the Fifth George Vanderbilt Expedition

(1041). Acad. Nat. Sci. Phila., Monogr. No. 6, pp.

349, 373-374, 378, 408.

Auxis thnznrd. Euthynuus lineatus, Katsuwonus
pelamis, Thunnus thynnus: records of capture;
synonymy. Pacific records of A. thazard, Euthyn-
ntis allettcratus, E. lineatus, Oermo alalunga, K.
pelamis, Neothunnus argentirittatus, and Thunnus
thynnus; description of T. thytinus; figure of E.
lineatus.
1949. The fishes of Oceania-Supplement 8. Mem. Ber-

nice P. Bishop Mus., vol. 12, No. 2, pp. 73-74.
Auxis thazard, Euthynnus wallisi, Katsuwonus
vagans, Neothunnus maoropterus, Parathunnus sibi:
listed ; synonymy.
Fowler, Henry W., and Stanley C. Ball.

1925. Fishes of Hawaii, Johnston Island, and Wake

Island. Bull. Bernice P. Bishop Mus., No. 26, p. 11.
Euthynnus alletteratus: listed.

Fraser-Brunner, a.

1949. On the fishes of the genus Euthynnus. Ann. and
Mag. Nat. Hist., vol. 2, No. 20, pp. 622-628.

Euthynnus afflnis afflnis, E. afflnis lineatus, E.
nffinis yaito: classification; distribution; figured;
key ; synonymy,
mw. The fishes of the family Scombridae. Ann. and
Mag. Nat. Hist., vol. 3, No. 26, pp. 131-163.
Allothunnus fallai, Auxis thazard, Euthynnus
afflnis, E. pelamis, Thunnus alalunga, T. albacora,
T. obestis, T. thynnus, T. tonggnl. T. zacalles:
classification ; description ; distribution ; key ; fig-
ured ; synonymy.

Fu.JiTA, K.. and Y. Wakita.
1915. A list of fishes from Kishu. Proc. Sei. Fish.
Assoc, vol. 1, No. 1, pp. 25-37. [J]

Auxis hira, A. niaru, Euthynnus yaito, Katsuwonus
pelamis, Thunnus alalunga, T. macroptcrus, T.
orientalis: listed ; Japanese common names.

FUKUDA, M., and S. Iizuka.

1940a. Experimental tima fishing. Prog. Rpt. Kuma-
moto Pref. Fisli Expt. Sta. for 1938, pp. 15-20. [J]

[P]

Big-eyed tuna, black tuna : Uyukyu Islands, catch in

relation to water temperature.
1940b. Skipjack tagging experiment. Prog. Rjit. Kuma-
moto Pref. Fish. Expt. Sta. for 1938, p. 21. [J] [P]

Japan : release records of tagged skipjack.

Gilbert, Charles H., and Edwin C. Starks.

1904. The fishes of Panama Bay. Mem. California.
Acad. Sci., vol. 4, p. 206.

Germo alalunga, Thunnus tliynnus: recorded.

GoDSiL, Harry C.

1938. Tuna tagging. California Fish and Game, vol. 24,
pp. 245-250.

Skipjack, yellowfin tuna : tagging methods and
release records.

1948. A preliminary population study of the yellowfin
tuna and the albacore. California Div. Fish and
Game, Fish Bull. No. 70, 90 pp.

Xcothunnus macropterus, Thunnus gcrmo: morpho-
metric data ; population relationships of Japanese,
Hawaiian, and California fish analyzetl ; methods
of taking morphometric measurements described.

1949. A progress report on the tuna investigations.
California Fish and Game, vol. 35, No. 1, pp. .5-9.

Albacore, yellowfin tuna : summary of population
studies based on morphometrical analysis.

GoDsiL, Harry C, and R. D. Byers.

1944. A systematic study of the Pacific tunas. C^ilifor-
nia Div. Fish and Game, Fish Bull. No. 60, 131 ppv
Kafsuiconus pelamis, Neothunnus macropterus.
Parnthunnus mehiiehi, Thunnus germo, T. thynnus:
proportional measurements; methods of measure-
ment ; internal anatomy ; key ; figures ; description ;
classification ; counts of meristic characters ;
anatomical differences between species listed ; pop-
ulation relationships discussed for all except P.
mebaehi.

GoDSiL, Harry C, and E. C. Greenhoou.

1948. Some observations on the tunas of the Hawaiian
region. California Div. Fish and Game. Bur. Mar.
Fi.sh., 8 pp. (Mimeographed.)

Albacore, black skipjack, skipjack, yellowfin tuna :
distribution.

Graham, David H.

1938. Fishes of Otago Harbour and adjacent seas with
additions to previous records. Trans. Roy. Soc. New
Zealand, vol. 68, pt. 3, p. 414.
Auxis thasard: listed.

8

FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE

Griffin, L. T.

1927. Additions to the fish fauna of New Zealand.
Trans. New Zealand Inst., vol. 58, pp. 140-141.

Germo germo: recorded; synonymy; description;
figured.
GiJNTHER, Albert.
1860. Catalogue of the Acanthopterygian fishes in the
collection of the British Museum. Vol. 2, pp. 363-366,
369. London.

Axixis rochei, A. tapcinoxnimi. Thynnus afflnis. T.
parifirim, T. pchimiis, T. thiinnina, T. ionggnl: de-
scription; distribution; synonymy.
1876. Die Fische der Siidsee. .Tour. JIus. GodefCmy, vol.
2, pp. 1.50-152.

Thynnus germo, T. pclamyn. T. thunnina. T. thyn-
nus: synonymy; description; distribution; T. germo
and T. thunnina figured.
1889. Report on the pelagic fishes collected by H. M. S.
Challenger during the years 187.3-76. Vol. 31, pt. 78,
p. 17. London.

Juveniles provisionally identified as Thynnus thun-
nina described and figured.
HjVKADA, Isokichi.

1928. A new species of Aeanthocephala from the Japa-
nese bonito, Euthynnus vagans. Japanese Jour. Zool.,
vol. 2, No. 1, pp. 1-4. [J]

Parasites.
Hart, J. L., and H. J. Holuster.

1947. Notes on the albacore fishery. Prog. Rpt. Pacific
Coast Sta., Fish. Res. Bd. Canada, No. 71, pp. 3-4.

Albacore catch correlated with water temperature
anil area ; stomach contents.
Hart, J. L.. et al.

1948. Accumulated data on albacore (Thnnnus ala-
lunga). Pacific Biol. Sta., Ilsh. Res. Bd. Canada, Circ.
No. 12, 8 pp.

Stomach contents ; size composition ; catch corre-
lated with area, water temperature, and season.
Hasegawa, Kiichi.

1937. Progress report of experimental tuna fishing in
the waters ad.1acent to Woleai. South Sea Fish. News,
No. 1, pp. 3-7. [J] [P]
Tunas : distribution.
H.iTAi. Shinkishi, et al.

1941. A symposium on the Investigation of skipjack and
tuna spawning grounds. South Sea Sci., vol. 4,
No. 1, pp. 64-75. [J] [P]

Skip.iack : Japan, Indo-Pacific region. South Seas ;
eggs ; juveniles ; food ; migration ; sexual maturity ;
probable spawning areas and seasons ; method of
differentiating between male and female skipjack.
Black tuna: Jaiian, Philippine region; probable
spawning areas and season; sexual maturity; de-
scription of eggs. YcUowfin tuna: sexual maturity
and probable spawning season in Indo-Pacific region.
Big-eyed tuna : juveniles recorded from South Seas.
Herald, Eaul S.

1949. Pipefishes and seahorses as food for tuna. Cali-
fornia Fish and Game, vol. 35, No. 4, p. .';29.

Euthynnus yaito, yellowfln tuna: stomach contents,

Herre, Albert W.

1932. A check list of fishes recorded from Tahiti. Jour.
Pan-Pacific Res. Inst., vol. 7, No. 1, p. 3.

Euthynnus alletcraius, E. iwlnniix, Ncnihunnus ma-
croptenis: listed.
19.33. A check list of fishes from Dumaguote, Oriental
Negros, P. I., and its immediate vicinity. Jour. Pan-
Pacific Res. Inst., voL 8, No. 4, p. 7.
Euthynnus yaito, Katsmvonus pelamis: listed.

1935. A check list of the fishes of the Pelew Islands.
Mid-Pacific Mag., vol. 47, No. 2, p. 104.

Katsnirnnios prlnmis, Neothnnnus mncropterua:
listed.

1936. Fishes of the Crane Pacific Expedition. Field
Mus. Nat. Hist., Zool. Ser., vol. 21, pp. 105-107.

Katsuiconus pelamis, NcotJiunnus macropterus,
Thunnus thynnus: distribution; synonymy: obser-
vations of N. macroptcnis fin lengths noted.
1940. Distribution of the mackerpl-like fishes in the

western Pacific north of the equator. Proc. Sixth

Pacific Sci. Cong., vol. 3, pp. 211-215.

Auxis thazard, Euthynnus allcterata. E. yaito,
Oermo alalunga, KntsnioonHS pelamis, Neothunnus
macropterus, N. rarns. Parathunntts siii, Thunnus
thynnus: distribution.

Herre, Albert W., and Agustin F. Umall.

1948. English and local common names of Philippine

fishes. U. S. Fish and Wildlife Serv., Circ. 14, 128 pp.

Auxis thaxard, Etithynnus yaito. Germo ahiiunga,

Eatsuioonus pela)nis, Neothunnus macropterus:

listed.

HiGASHi, Hideo.

1940a. Utilization of fishery byproducts from the South

Seas (3). South Sea Fish., vol. 6. No. 7, pp. 13-20.

tJ] [P]

Big-eyed tuna, black tuna, skipjack, yellowfin tuna :

ratio of viscera weight to body weight.

1940b. Utilization of fishery byproducts from the South

Seas (7). South Sea Fish., vol. 6, No. 12, pp. 10-13.

[J] [P]

Skipjack ; ratio of viscera weight to body weight ;

proportional measurements of various body parts.

1941a. Utilization of fishery byproducts from the South

Seas (8). South Sea Fish., vol. 7, No. 1, pp. 33-37.

[J] [P]
Skipjack : length-weight data ; proportional meas-
urements of various body parts ; liver figured.
1941b. Utilization of fisliery liyproducts from the South
Seas (10). South Sea Fish,, vol. 7, No. 3. pp. 32-39.

[J] [P]

Katxuu-onus r'agans, Neothunnus macropterus: pro-
portional measurements of various body parts ; ag ,
analysis. I

1941c. Utilization of fi.shery byproducts from the South
Seas (14). South Sea Fish., vol. 7, No. 8, pp. 30-43.

[J] [P] I

Big-eyed tuna, yellowfin tuna : length-weight data ; i
proportional measurements of various body parts ;
livers figured.

BIBLIOGRAPHY ON PACIFIC TUXAS

9

llKiAsni, Hideo — Continued
1942. Record of experimer.ts on flslies of the South
Seas. South Sen Fish., vol. S, No. 11, pii. i:?-27.

[J] [P]
Kutxiiiconiis vagans, Ncothiinniis macroptcni.i,
Parathunniis siii: len.sth-weight data; proportional
measurements of various body parts.

Hic.AsHi, HiDKo, and Ma,s.\o Hirai.
1!)48. The nicotinic acid content of flsh. Contrib. Cent,
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[Jk]
Sldpjack, yellowfln tuna : nicotinic acid content of
various body parts.

Hii.ur.nRAND, Samuki, F.

1940. A descriptive catalog of the shore fishes of Peru.
U. S. Natl. Mus., Bull. 189, pp. 361-372.
Eiithynnus alleterata, Katsuwomtg pclamis, Tlnin-
tiiis iiiacroptenis: classification; description; syn-
onymy; distribution; food; key. Thininiis (jermo,
2'. thynnus: key; occurrences recorded.

HiBATStJKA, HiTosHi, and Kaku.ji Imaizumi.

19.34. Experimental fishing and investigation in south-
ern venters. Prog. Rpt. Formosa Govt. -Gen. Fish.
Expt. Sta. for WSC'. Fish. Sec, pp. 97^164. [.I] [P]
Yellowfln tuna : Indo-Pacific region ; length-weight
data: fishing eoiulitions in relation to oceanography
and weather; catch per unit of effort; distribution.
HiBATsuKA, HiTosni, and Kiyoji Ito,

1934. Rep<irt on experimental tuna fishing in the Celebes
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for 1934, pp. 1-2S. [J] [P]

Yellowfin tuna ; length-weight data ; fishing condi-
tions in relation to oceanography and weather;
catch per unit of effort; distribution.
HiRATstrivA, HiTosHi, and Seiichi Mobxta.

193."). Correlation between length and weight of yellow-
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IPl

IIol.DEl;, CHART.es FliKDERICK.

1912. The fishes of the Pacific coast. Pp. l.'5-42. New
York.

Thininus ahilmif/fi, T. macriiptvnix, T. iiidciildtus,
T. tJiynnus: distribution ; figures of all except '/'.
macropterus.

HuBBS, Carl L.

1916. A second record of the scombroid fish Gcrmo
tiiacroptcriis fr(mi the coast of California. Copeia,
No. 38, p. 93.
1928. A check-list of the marine fishes of Oregon and
Washington. Jour. Pan-Pacific Res. Inst., vol. 3, No. 3,
p. 12.

Gcrmo alalungn : Oregon; recorded.

Ietiisa, Satoru.
19.39. Catch of tunny in the seas south of Kyushu. Bull,
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'J'Inniinis oriotl'tlis: catches correlated with water
temperature.

IKEBE, KENZO.

19.39. On the age of yellowfln tuna talcen in Palau
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[J] [P]
Length-weight data ; body condition : sexual ma-
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1940a. Age and measurements of tunas in Palau waters.
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Big-eyed tuna, yellowfin tuna : length-weight data ;
age analysis of yellowfin tuna based on size groups.
19401). Measurements of yellowfin tuna taken south of
the Marshall Islands. South Sea Fish. News, vol. 4,
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Length-weight (lata ; age analysis ba.sed on size
groups.
1940e. Measurements of albacore and yellowfin tuna
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Length-weight data ; age analysis.
1940d. Investigation of tunas in I'alau waters. South
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Catch of yellowfin tuna correlated with currents.
1941a. Measurements of yellowfin tuna from the Equa-
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Length-weight and ago data ; a.ge composition of
catches noted.
1941b. A contribution to the study of tuna spawning
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South Seas ; probable tuna spawning grounds ;

length-weight and age data of Immature yellowfin

tuna.

1942. Report of the investigation of tuna fishing in tlie

Timor, Arafura, and Banda Seas. South Sea Fi.sh.,

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Big-eyed tuna, yellowfin tuna; fishing conditions
correlated with oceanography.
iKEBE. Kenzo, and Takeshi Matsimoto.

1937. Progress report on exiierimental skipjack fishing
near Yap. South Sea Fisli. News. No. 4, pp. .3-9.

[J] [P]

Skipjack : length-weight data ; sex and body condi-
tion recorded.
Imaizumi, Kakuji.

1937. An account of the investigation of tuna fishing
grotnids in the East Philippine Sea. Formosa Fish.
Mag.. No. 271, pp. 0-23. [J] [P]

Albacore, big-eyed tuna, yellowfin tuna: catch per
unit of effort; distribution; sexual maturity of
yellowfln tuna.

IMAMI'RA. YUTAIvA.

1949. The skipjack fishery. Text Fish., vol. 6. pp. 17-
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Aiixis hira, A. mam, Euthijnniis yaito: Japan;
description; distribution; ha'bits. KatsuHonus
pchimiH: Japan; anatomy; description; distribu-
tion ; migration ; spav.ning areas and season ; food ;
populations; habits; natural enemies; fishing con-
ditions in relation to oceanography.

10

FISHERY BULLErriN OF THE FISH ANI> WTLDLIFE SEEVICB

INANAMI, YOSHITUKI.

1940a. Relationship of viscera weight to body weight in
yellowfin tuna. South Sea Fish. News, vol. 4, No. 2,
pp. 2-7. [J] [P]
1940b. Tuna fishing conditions and currents along the
eastern coast of the Palau Islands. South Sea Fish.
News, vol. 4, No. 2, pp. 7-10. [J] [P]

Big-eyed tuna, yellowfin tuna : fishing conditions
correlated with currents.
1940c. Oceanography and fishing conditions in central
Palau waters. South Sea Fish. News, vol. 4, No. 3,
pp. 5-7. [J] [P]

Big-eyed tuna, yellowfin tuna : fishing conditions
correlated with currents and water color.
1941. Oceanographlc changes and fishing conditions in
Palau waters. South Sea Fish. News, vol. 5, No. 2,
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Skipjack, yellowfin tuna : fishing conditions corre-
lated with water temperature, currents, salinity.
1942a. Oceanographlc conditions and yellowfin tuna
fishing grounds in South Sea Island waters. South
Sea Fish. News, vol. 6, No. 1, pp. 2-5. [J] [P]

Location of fishing grounds correlated with cur-
rents, transparency, water color, and water tem-
perature.
1942b. Skiiijaek fishing conditions in Saipan, Truk, and
Ponape. South Sea Fish. News, vol. 6, No. 1, pp. 5-7.

[J] [P]

Seasonal fluctuations in commercial catch ; size
composition.
1942c. Small skipjack caught at Truk. South Sea Fish.
News, vol. 6, No. 1, p. 7. [J] [P]

Records and measurements of juveniles.
1942d. Report of grounds fished by tuna boats ojier-
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Albacore, big-eyed tuna, skipjack, yellowfin tuna :
fishing conditions correlated with water tempera-
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Japanese Bureau of Fishemes.

193.3. Report of the southern fisheries investigation for

1931. Bur. Fish., Min. Agr. and For., Japanese Imp.
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1934. Report of the southern fisheries investigation for

1932. Bur. Fish., Min. Agr. and For., Japanese Imp.
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Big-eyed tuna, yellowfin tuna : Indo-Pacific region ;
distribution ; catch correlated with water tempera-
ture and transparency ; stomach contents of yellow-
fin tuna.

1935. Report of the southern fisheries investigation for

1933. Bur. Fish., Min. Agr. and For., Japanese Imp.
Govt., 298 pp. [J]

19.39. Results of encouragement given to the exploitation
of albacore fishing grounds during 1938. Bur. Fish.,
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[J] [P]
Albacore : mid-Pacific region : morphometric data ;
stomach contents ; catch correlated with water tem-
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eyed tuna : catch correlated with water tempera-
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Japanese Bttkeat: of Fisheries — Continued

1940. Results of encouragement given to the exploitation
of albacore fishing gi-ounds during 1939. Bur. Fish.,
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Albacore : mid-Pacific region ; morphometric data ;
Stomach contents ; catch correlated with water tem-
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effort ; distribution.
1942. Results of encouragement given to the exploitation
of albacore fishing grounds during 1940. Bur. Fish.,
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Jenkins, Glivter P.

1903. Report on collections of fishes made in the Ha-
waiian Islands with descriptions of new species. Bull.
U. S. Fish. Comm. for 1902, vol. 22, p. 441.

Auxis thaxard, Ginnnosarda alletterata, G. pelamis;
listed ; synonymy.

Jordan, Davto Starr.
1885. A list of the fishes known from the Pacific coast
of tropical America, from the Tropic of Cancer to
Panama. Proc. U. S. Natl. Mus., vol. 8, No. 24, p. 373.
Orcynus alalonga: recorded.
1923. A classification of fishes including families and
genera as far as known. Stanford Univ. Publ., Univ.
Ser., Biol. Sci., vol. 3, No. 2, pp. 179-180.
Classification and synonymy of Thunnidae.

Jordan, David Starr, and Barton Warren Eveemann.
1896. A check-list of the fishes and fish-like vertebrates
of North and Middle America. Rpt. U. S. Fish Comm.
for 1895, p. 340.
Auxis tliaxard, Ocrmo ahilunga, Gymnosarda pela-
mis, Thynnus thynnus: distribution; English com-
mon names ; synonymy.
1905. The aquatic resources of the Hawaiian Islands.
I. The shore fishes of the Hawaiian I.slands, with a
general account of the fish fauna. Bull. U. S. Fish
Comm. for 1903, vol. 23, pt. 1, pp. 171-175.
Atixis thaxard, Germo gcrmo, Oyiunosarda allet-
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onymy; Hawaiian common names for all except
A. thasard.
1926a. A check-list of the fishes of Hawaii. Jour. Pan-
Pacific Res. Inst., vol. 1, No. 1, p. 8.

KulhynvKS yaito, Germo germo, KisliinoeUa rara,

Ncothminus macroptenis, Neothunnus n. sp., Para-

thiinnus sibi, Thunnus oricntalis: recorded.

1926b. A review of the giant mackerel-like fishes,

tunnies, spearfishes, and swordfishes. Occas. Papers

California Acad. Sci., No. 12, pp. 8-25.

Germo germo, KisliinoeUa rara, K. zacalles n. sp..
Neothunnus catalinae n. sp., JV. itosibi n. sp., N. ma-
eropteriis, N. tonggol, Purathunniis sibi, Thunnus
maccoyii, T. orientalis, T. phiUipsi n. sp., and T.
saliens n. sp. : keys ; description ; distribution ; syn-
onymy of G. germo, P. sibi, T. maccoyii, T. orien-
talis; Japanese common names of ^. rara, N. itosibi,
N. macropterus ; figures of G. germo, K. zacalles, N.
catalinae, N. itosibi, N. macropterus, P. sibi, T.
phillipsi, T. saliens.

BIBLIOGRAPHY ON PACIFIC TITN-AS

11

Jordan, David Starr, and Chari.es Henry Gii3ERt.

1881a. Descriptions of two new sijecies of scopelid
fishes (Sudis ringens and Myctophum crciiuUire) from
Santa Barbara Channel, California. Proc. U. S. Natl.
Mus., vol. .3, p. 273.

Specimens fonnd in food of Orcynus alalonga.
1881b. List of the fishes of the Pacific coast of the
United States, with a table showing the distribution
of the six-cies. Proc. U. S. Natl. Mus., vol. 3, p. 456.
Orri/niiK alnloniia : recorded.
1882. Notes on the fishes of the Pacific coast of the
United States. Proc. U. S. Natl. Mus., vol. 4, p. 45.
Orcynus alalonga: distribution; synonymy; habits;
food.
Jordan, David Starr, and Carl Leavitf Hubbs.

1925. Record of fishes obtained by David Starr Jordan
in Japan, 1922. Mem. Carnegie Mus., vol. 10, No. 2,
pp. 21.5-221.

Aiixis hira, A. tapcinosoma, EutJiynniis yaito,
Oenno germo, Kalsuwotiiis vagans. Kisliinoella
ram, Xcothunnus macroptcnis, Parathnnnus sibi,
Thunnus oi'ientalis: recorded; descriptions of A.
hira, A. tapcitioaoma, G. gcnno, K. rara. N. marrop-
tenig, P. sibi and T. orientalis; synonymy of A.
tapcinosoma, E. yaito, Gf. germo, N. niacropterus,
P. sibi, and T. orientalis; Japanese common names
of all but A. hira and E. yaito; key to Katsuwonidae
and Thunnidae.
Jordan, David Starr, and Eric Knight Jordan.

1922. A list of the fishes of Hawaii, with notes and
descriptions of new species. Mem. Carnegie Mus., vol.
10, No. 1, pp. 31-33.
Aiixis thazard, Euthynnus allctcratus, E. pclamis,
Germo alalunga, O. aryentivittatus, G. macroptcnis,
O. sibi, Thinniiis orientalis, T. thynniis: listed;
descriptions of G. alalunga, O. macropicrits, O. sibi,
and T. orientalis ; Hawaiian common names of E.
alleteratus, E. pelamis, and G. macropterus.
.Jordan, David Starr, and Charles Metz.

1913. A catalog of the fishes known from the waters of
Korea. Mem. Carnegie Mus., vol. 6, No. 2, p. 26.
Anxis thazard: Japanese common names; distribu-
tion.
Jordan, David Starr, and Alvin Seale.

1906. The fishes of Samoa. Bull. U. S. Bur. Fish., vol.
25, p. 228.

Auxis thazard, Germo germo, O. macropterus,
Oymnosarda ullctcrata, G. pelamis: distribution.
Jordan, David Starr, and J. O. Snybeb.

1900. A list of fishes collected in Japan by Kelnosuke
Otaki, and by the United States Steamer .\lbatross,
with descriptions of fourteen new species. Proc.
U. S. Natl. Mus., vol. 22, p. .352.

Axixis thazard and Thunnus schligelt: listed.

1901. A preliminary check list of the fishes of Japan.
Annot. 2yool. Jap., vol. 3, pts. 2 and 3, p. 64.

Avxis tapcinosoma, Germo macropterus, (1. sibi,
Oymnosarda afflnis, Q. allctcrata, Thunnus schle-
geli: listed ; Japanese common names.

Jordan, David Starr, and Edwin Chapin Stabks.

1007. Notes on fishes from the island of Santa Catalina,
southern California. I'roc. U. S. Natl. Mus., vol. 32,
pp. 69-70.

Germo macropterus: records; synonymy; descrip-
tion; figured. O-ymnosarda pelamis: distribution.

JORnAN, David Starr, S. Tan.\IvA, and J. O. Snyder.
1913. A catalojme of the fishes of Japan. Jour. Coll.
Sci., Imp. Univ. Tokyo, vol. 33, art. 1, pp. 119-121.
Auxis thasard, Euthynnus alleteratus, E. vagans,
Thunnus alalunga, T. macropterus, T. thynnus:
synonymy ; distribution ; Japanese common names ;
A. thazard and E. alleteratus figured.

Kaooshima Pbefectural Fisheries Experiment Station.

1925. Experimental skipjack fishing. Prog. Ept. Kago-

shima Pref. Fish. Expt. Sta. for 1923, pp. 1-37. [J]

[P]

Ryukyu Islands ; skipjack fishing conditions corre-
lated with water temperature; length-weight, girth
data.
1926a. Experimental skipjack fishing. Prog. Rpt. Kago-
shima Pref. Fish. Expt. Sta. for 1924, pp. 1-51. [J]

[P]
Ryukyu Islands; skipjack fishing conditions corre-
lated with water temperatures ; length-weight and
girth data ; records and de.seriptions of scombroid
juveniles (also reported in Kishinouye, 1926).
1926b. Experimental longline fishing for tuna. Prog.

Rpt. Kagoshima Pref. Fish. Expt. Sta. for 1924,

pp. 52-66. [J] [P]

Big-eyed tuna, skipjack, yellowfin tuna : Ryukyu
Islands ; catches correlated with water tempera-
ture.
1927a. Experimental longline fishing for tuna. Prog.

Rpt. Kagoshima Pref. Fish. Sta. for 1925, pp. 38-53.

[J] [P]
Albacore, big-eyed tuna, black tuna, yellowfin tuna :
Ryukyu Islands ; catches correlated with water
temperature.
1927b. Experimental skipjack fishing. Prog. Rpt. Kago-
shima Pref. Fish. Expt. Sta. for 1925, pp. 1-38. [J]

[P]
Ryukyu Islands ; skipjack fishing conditions corre-
lated with water temijerature and currents ; length-
weight and girth data ; records and descriptions
of scomliroid juveniles (also reported in Kish-
inouye 1926).
1928a. Experimental skipjack fishing. Prog. Rpt. Kago-
shima Pref. Fish. Expt. Sta. for 1926, pp. 1-22. [J]

[P]
Ryukyu Islands ; skipjack catch correlated with

water temperature and currents; length-weight and

girth data ; release reccu'ds of tagged fish.

1928b. Experimental longline fishing for tuna. I'rog.

Rpt. Kagoshima Pref. Fish. Expt. Sta. for 1926, pp.

22-37. [J] [P]
Albacore, big-eyed tuna, black tuna, yellowfin tuna :
Ryukyu Islands; catches correlated with water
temperature.

12

FISHEKY BULLETIN OF THE FISH AND WILDLIFE SERVICE

Kagoshima Pkefectural Fisheries Experiment Sta-
tion — Continued
1929a. Experimental sliipjack fishing. Prog. Rpt. Kago-
shima I'ref. Fish. Expt. Sta. for 1927, pp. 1-20. [J]

[P]

Ryuliyu Islands ; skipjack catch correlated with

water temperature; length-weight and girth data.
1929b. Experimental longline fishing for tuna. Prog.
Rpt. Kagoshima Pref. Fish. Expt. Sta. for 1927, pp.
20-34. [J] [P]

Big-eyed tuna, yellowfin tuna : Ryukyu Islands ;

catches correlated with water temperature.
1930a. Experimental skipjack fishing. Prog. Rpt. Kago-
shima Pref. Fish. Expt. Sta. for 1928, pp. 1-18.

[J] [P]

Ryukyu Islands; skipjack catch correlated with

water temperature.
1930b. Experimental longline fishing for tuna. Prog.
Rpt. Kagoshima Pref. Fish. Expt. Sta. for 1928, pp.
18-31. [J] [P]

Albacore, big-eyed tuna, yellowfin tuna : Ryukyu

Islands ; catches correlated with water temperature.

1930c. Experimental fishing l)y small motor vessels :

Experimental longline fishing for albacore. Prog. Rpt.

Kagoshima Pref. Fish. Expt. Sta. for 1928, pp. 54-60.

[J] [P]
Albacore, big-eyed tuna, black tuna, yellowfin tuna :
Ryukyu Lslands ; catches correlated with water
temperature.
1931a. Experimental skipjack fishing. Prog. Rpt. Kago-
shima Pref. Fish. Expt. Sta. for 1929, pp. 1-lG.

[J] [P]
Ryukyu Islands ; skipjack catch correlated with wa-
ter temperature.
1931b. Experimental longline fishing for tuna. Prog.
Rpt. Kagosliima Pref. Fish. Expt. Sta. for 1929, pp.
16-.30. [.I] [P]

Albacore, big-eyed tuna, yellowfin tuna : Ryukyu
Islands ; catches correlated with water temperature.
1932a. Experimental skipjack fishing. Prog. Rpt. Kago-
shima Pref. Fish. Expt. Sta. for 1930, pp. 1-20.

[J] [P]
llyukyu Islands ; skipjack fishing conditions corre-
lated with water temperature.
19.32b. Experimental longline fl.shing for tuna. Prog.

Rpt. Kagoshima Pref. Fish. Expt. Sta. for 1930, pp.

21-28. [J] [P]

Albacore, big-eyed tuna, black tuna, yellowfin tuna :
Ryukyu Islands ; catches correlated with water
temperature.
1932c. Exiierimental longline fl.shing for albacore and

pole and line fishing for mackerel. Prog. Rpt. Kago-

.shima Pref. Fish. Expt. Sta. for 1930, pp. 54-59.

[J] [P]
Ryukyu Islands ; albacore catch correlated with wa-
ter temperature.

Kagoshima Pretectural Fisheries Experiment Sta-
tion — Cont inued
1933a. Investigation of skipjack fishing. Prog. Rpt.
Kagoshima Pref. Fish. Expt. Sta. for 1931, pp. 1-16.
[J] [P]
Ryukyu Islands, Philippine region ; skipjack fishing
conditions correlated with water temperature.
1933b. Experimental longline fishing for tuna. Prog.
Rpt. Kagoshima Pref. Fish. Expt. Sta. for 1931, pp.
16-23. [J] [P]

Albacore, big-eyed tuna, yellowfin tuna : R.Mikyu
Islands ; catches correlated with water tempera-
ture.

19.35. Investigation of skipjack fishing. Prog. Rpt.
Kagoshima Pref. Fish. Expt. Sta. for 1933, pp. 1-12.
[J] [P]
Ryukyu Islands ; skipjack fishing conditions corre-
lated with water temperature.
1936a. Investigation of skipjack fishing. Prog. Rpt.
Kagoshima Pref. FLsh. Expt. Sta. for 1934, pp. 1-16.
[J] [P]
Ryukyu Islands ; skipjack fi.shing conditions corre-
lated with water temperature ; length-weight data.
1936b. Investigation of the migration of important
fishes. Prog. Rpt. Kagoshima Pref. Fish. Expt. Sta.
for 1934, pp. 86-87. [J] [P]

Ryukyu Islands ; release records of tagged skipjack.
1937. Investigation of skipjack fishing. Prog. Rpt.
Kagoshima Pref. Pish. Expt. Sta. for 1935, pp. 1-8.
[J] [P]
Ryukyu Islands; skipjack catch correlated with
water temperature ; length-weight data ; size com-
position of catch.
1938a. Investigation of skipjack fishing. Prog. Rpt.
Kagoshima Pref. Fish. Expt. Sta. for 1936, pp. 1^.
[J] [P]
Ryukyu Islands ; skipjack length-weight data.
193Sh. Investigation of the migration of important
fishes. Prog. Rpt. Kagoshima Pref. Fish. Expt. Sta.
for 1936, p. 89. [J] [P]

Ryukyu Islands ; release records of tagged skipjack.
1939a. Investigation of skipjack fishing. Prog. Rpt.
Kagoshima Pref. Fisli. Expt. Sta. for 1937, pp. 1-3.
[J] [P]
Ryukyu Islands ; skipjack length-weight data.
1939b. Investigation of the migration of important
fishes. Prog. Rpt. Kagoshima Pref. Fish. Expt. Sta.
for 1937, p. 69. [J] [P]

Ryukyu Islands ; release records of tagged skipjack.
1940a. Experimental .skipjack fishing. Prog. Rpt.
Kagoshima Pref. Fish. Expt. Sta. for 1938, pp. 1-3.
[J] [P]
Ryukyu Islands; skipjack length-weight data.
1940b. Investigation of the migration of important
fishes. Prog. Rpt. Kagoshima Pref. Fish. Expt. Sta.
for 1938, p. 43. [J] [P]

Ryukyu Islands; release records of tagged skipjack.

BIBLIOGRAPHY ON PAaFIC TUNAS

13

Kaooshima Prefectural Fisheries Experiment Sta-
tion — Continued
1941. Investigation of skipjaclc fishin;^. I'ro^:. Kpt.
Kagoshima Pref. Fish. Expt. Sta. for 1939, pp. 1-3.
[J] [P]
Ryuk.vu Islands ; skipjack length-weight data.
Kaxamura, Ma.sami, and Kakuji Imaizumi.

1935. Report on pxp<>rimental fishinir by tlio Shonan
Maru in 1935 : Report of exijerimenlal longline fl.shing
for tuna in eastern Formosan waters. Formosa
Govt.-Gen. Fish. Expt. Sta. Publ., No. 3, pp. 165-202.
[J] [P]
Big-eyed tuna, yellowfln tuna : length-weight data ;
body temperatures : sexual maturity ; catch per
unit of effort ; fishing conditions in relation to
oceanography and weather ; distribution.
KANAMfBA. Masami, and Hauuo Yazaki.

1940a. Report on experimental fishing by the Shonan
Maru in 1937 : Investigation of tuna longline fishing
grounds in the East Philippine Sea. Formosa Govt.-
Gen. Fish. Expt. Sta. Publ., No. 21, pp. 1-G5. [J] [P]
Albacore, big-eyed tuna, skipjack, yellowfin tuna :
catch iJer unit of effort: distribution of yellowfln,
big-eyed tuna, and skipjack : yellowfln tuna : stom-
ach contents ; body temperature and relation to
water temperature ; length-weight data : body con-
dition; age analysis; sexual maturity; flsliing con-
ditions in relation to oceanography and weather.
1940b. Report of tlie investigation of fishing grounds by
the Shonan Maru in 1937: Investigation of tuna long-
line fishing grounds in the South China Sea. Formosa
Govt.-Gen. Fish. Expt. Sta. Publ., No. 21, pp. 67-117.
[J] [P]
Albacore, skipjack, yellowfin tuna : distribution ;
catch per unit of effort : fishing conditions in rela-
tion to oceanograpliy and weather : albacore, yel-
lowfln tuna: stomach contents; body temperature;
length-weight data; body condition; age analysis;
sexual maturity.
Kato, Genji.

1940. An account of longline flshing for tuna. South
Sea Fish. News. vol. 4, No. 7, pp. S-10. [J] [P]
Sexual maturity of yellowfln tuna noted.
Kawamira. Hyozo.
1939. Observations on oceanography and fisliing condi-
tions in Palau waters. South Sea Fish. News, vol. 3,
No. 1, pp. 2-6. [.T] [P]

Fishing conditions for yellowfin tuna and skipjack
correlated with oceanography.
Kawana, Takeshi.

1934. Tuna fishing in relation to oceanographic condi-
tion.s. Prog. Rpt. Hokkaido Fish. Expt. Sta., vol. 31,
pp. 1-180. [J] [P]

Tln)}iiiiis orioitalis: Japan; flshing conditions cor-
related with astronomical and oceanographic fac-
tors ; tagging ; size composilion of commercial catch.
1937. The catch of tunny. Tliutinus oricntiilis T. and S.,
off Kushiro, Hokkaido, in relation to the vertical
difference in water temperature. Bull. Japanese Soc.
Sci. Fish., vol. 6, No. 2, pp. 73-74. [Je] ll'J

KiDA. Takeo.

193(>. On the surface temperature of water in the tunny

flshing grounds off Kushiro and Urakawa in summer.

Bull. Japanese Soc. Sci. Fish., vol. 5, No. 2, pp. 87-90.

[Je]

Thjinnus thj/'inii'i: fishing conditions correlated

with water temperature ; size composition of

schools ; habits.

KiMfltA, Kl.NOSUKE.

1932. Growth curves of blue-fin tuna and yellow-fin tuna
based on the catches near Sigedera, on the west coast
of I'rov. Idu. Bull. Japanese Soc. Sci. Fi.sh., vol. 1,
No. 1. pp. 1-4. [Je] [PJ

Ncotliiinntis inacroptrnis, T h u ii n u n orioitalis:
growth rates determined from size groujis.
1935. Statistical analy.sis of the catch by keddle nets,
along the coast of Surugu Bay. Rec. Oceanogr. Works,
vol. 7, No. 1, pp. 1-.3G. [JE]

Growth of Ncothiinnus macroptcnis ; age and size
groups of Thunnus orient a! if.
1941. Skipjack fishing. Fish. Technol. Lect. .Ser., No. 4,
36 pp. [J]

Pacific Ocean ; distribution ; migration ; catch corre-
lated with water temperature : age and size composi-
tion of commercial catches.
1942a. Tuna and spearfish fishing conditions. Fish.
Technol. Lect. Ser., No. 5, 122 pp. [J]

Albacore, big-eyed tuna, yellowfin tuna : Japan,
Indo-Pacific region. South Seas : fishing conditions
correlated with water temperature; age and size
composition of albacore and yellowfin tuna.
1942b. Oceanic resources : Offshore fisheries. Sci. Sea,
vol. 2, No. 3, pp. 142-147. [J] [P]

Albacore, black tuna, skipjack : Pacific Ocean ; dis-
tribution : migration ; distribution of big-eyed tuna
and yellowfin tuna.
1949. Atlas of skipjack fishing grounds — with data on
the albacore grounds. Kuroshio Publ. Co., Tokyo,
44 pp. [J]

Japan ; catches of albacore and skipjack correlated
with surface water temperature.
KiMuitA, KiNosuKE, aud Kazimi Ishii.

1933. Statistical analy.sis of the catch at the north-
eastern end of Surugu Bay. Bull. Japanese Soc. Sci.
Fish., vol. 2, No. 2, pp. 69-79. [Je]

Catches of yellowfin tuna correlated with water
temperature.

KlSHINOUYE, KaMAKICIII.

1895. Food of tunas and bonitos. Zool. Mag., vol. 7,
p. 111. [J]

191,5a. Studies on the mackerels, cybiids, and t\uias.
Proc. Sci. Fish. Assoc, vol. 1, No. 1, pp. 1-24. [J] [P]
Auxis hira n. sp., A. maru n. sp., Eiithi/iiiiiis yaito
n. sp., Katsmconus pelamys n. sp., Thunnus ala-
lunga, T. macroptcnis, T. mebachi a. sp., T. oricn-
talis. T. rarus n, sp, : internal anatomy ; classifica-
tion ; description ; distribution ; keys ; Japanese com-
mon names; figures; spawning of T. orioitalis and
A. maru; food and habits of tunas in general.

14

FISHEKT BULLErriN OF THE FISH ANiD WILDLIFE SERVICE

KisHiNOUYE, Kamakichi — Continued

1915b. Anatomical aspects of darli muscle. Proc. Sci.
Fish. Assoc, vol. 1, No. 2, pp. 12S-136. [J] [P]
Albacore, big-eyed tuna, black skipjack, black tuna,
frigate mackerel, Ncoihunntis rariis, skipjack, yel-
lowfin tuna : anatomy and vascular system of lat-
eral musculature described ; figured in part for all
except big-eyed tuna and N. rams.
1917a. A new order of tbe Teleostomi. Proc. Sci. Fish.
Assoc, vol. 2, No. 2, pp. 1-4. [J] [P]

Classification; description of internal anatomy of
order Plecostei and families Tliunnidae and
Katsuwonidae.
1917b. The food of tunas. Proc Sci. Fish. Assoc, vol.
2, No. 1, pp. 106-108. [J] [P]

Albacore, big-eyed tuna, skipjack, yellowfin tvina :

stomach contents ; juvenile albacore, big-eyed tuna,

skipjack, and Auxis inaru recorded from stomachs

of adults.

191S. Amount of blood in the dark muscle and other

muscles of the Plecostei. Proc Sci. Fish. Assoc, vol.

2, No. 3, pp. 259-260. [J] [P]

Blood content of dark lateral muscle of big-eyed
tuna and skipjack compared.
1919a. Studies on the Plecostei. Proc. Sci. Fish. Assoc,
vol. 2, No. 4, pp. 269-274. [J] [P]

Evolution of various tuna species based on internal
anatomy ; vascular system and anatomy of lateral
musculature of Thunnidae and Katsuwonidae ; and
vascular plexuses of albacore, big-eyed tuna, black
skipjack, black tuna, frigate mackerel, skipjack,
and yellowfin tuna figured.
1919b. The larval and juvenile stages of the Plecostei.
Proc. Sci. Fish. Assoc, vol. 3, No. 2, pp. 49-53. [J]

[P]

Black skipjack, black tuna, skipjack : western
Pacific ; juveniles recorded and described ; markings
of young Scombroid fishes mentioned ; Liitken's
"albacore" juveniles and Giinther"s "black skip-
jack" juvenile described and figured.

1919c. Black skipjack from Mexico. Proc Sci. Fish.
Assoc, vol. .3, No. 2, p. 113. [J] [P]

Eiithjfniius lineatus: Mexico; recorded and de-
scribed as a new species.

1921. Tunas of the American coast. Proc Sci. Fish.
Assoc, vol. 3, No. 3, p. 2.39. [J] [P]
Anatomical differences between American bluefln
tuna and .Japane.se black tuna noted.

1922a. Air bladders of Thunnidae. Proc. Sci. Fish.
Assoc, vol. 3, No. 4, p. 304. [J] [P]

Albacore, big-eyed tuna, yellowfin tuna : air-blad-
ders described ; recorded and described for black
tuna.

1922b. Carangid-like markings of skipjack. Proc. Sci.
Fish. Assoc, vol. 3, No. 4, pp. 304-305. [J] [P]

Unusual markings on one specimen recorded and
described.

1922c. Black skipjack also found in Japan Sea. Proc
Sci. Fish. Assoc, vol. 3, No. 4, p. 305. [J] [P]
Distribution record.

KisHiNOUYE, Kamakichi — Continued

1923. Contributions to the comparative study of the so-
called Scombroid fishes. Jour. Coll. Agr., Imp. Univ.
Tokyo, vol. 8, No. 3, pp. 293^75. [P]

Au.ris hira, A. mam, Euthynnns lineatus, E. yaito,
Katsitioonus pelamis, Neothunnus macropterus, N.
rams, Paratliunnus mcbachi, Thinnuis ffcrnio, T.
orientalis: anatomy; bibliogi-aphy : classification;
description ; distribution ; figures ; food ; habits ;
keys ; Japanese common names ; synonymy ; growth
of N. macropterus, T. germo, T. orientalis; enemies
of T. orientalis; migration of K. pelamis, T. germo,
T. orientalis ; i>arasites of E. yaito, K. pelamis, N.
macropterus, P. niebnchi; spawning of E. yaito, K.
pelamis, N. macropterus, T. orientalis; young of
.4. mam, E. yaito, K. pelamis, T. germo, T. orientalis.

1924. Observations on skipjack fishing grounds. Proc.
Sci. Fish. Assoc, vol. 4, No. 2, pp. 87-92. [J] [P]

Auxis maru, Euthynnus yaito, Katsuwonus pelamis,
INeothunnus macropterus: Ryukyu Islands; rec-
ords and descriptions of juveniles.
1926. An outline of studies of the Plecostei (tuna and

skipjack) in 1925. Proc. Sci. Fish. Assoc, vol. 4,

No. 3, pp. 125-137. [J] [P]
Auxis sp., Katsuwonus pelamis, INeothunnus ma-
cropterus, "iParathunnus meiachi: Ryukyu Islands ;
juveniles recorded, described, and figured.

KiTAHAKA, T.

1897. Seombridae of Japan. Jour. Imp. Fish. Bur.,
Tokyo, vol. 6, pp. 1-3. [C]
Tliynnus germo, T. m.acropterus, T. pelaniys, T. .<sihi,
T. thunnina, T. thynnus: figures.

KOCHI PREFECTtni.\L FISHERIES EXPERIMENT STATION.

1923a. Oceiinographic observations and search for skip-
jack fishing grounds. Prog. Rpt. Kochi Pref. Fish.
Expt. Sta. for 1921, pp. 1-i. [J] [P]

Japan ; skipjack fishing conditions correlated with
oceanographic factors.
192.3b. Oceanographic observations and search for tuna
fishing grounds. Prog. Rpt. Kochi Pref. Fish. Expt.
Sta. for 1921, pp. 5-15. [J] [P]
Albacore, big-eyed tuna, yellowfin tuna : Japan ; mi-
gration ; vertical distribution.
1924. Oceanographic observations and search for tuna
fishing grounds. Prog. Rpt. Kochi Pref. Fish. Expt.
Sta. for 1922, pp. 39-49. [J] [P]
Albacore, big-eyed tuna, black tuna, yellowfin tuna :
Japan ; migi-ation ; vertical distribution.
KoDAMA, Masaharu, Kiyoshi Iizuka, and Toshi Harada.
1934. Weight ratio of various body parts and analyses
of the normal constituents of fresh flesh of important
South Sea fish. Prog. Rpt. Formosa Govt. -Gen. Fish.
Expt. Sta. for 1932, Technol. Sec, pp. 1-6 [J] [P]
Skipjack and tuna examined.

KUMAMOTO PrEFECTURAL FISHERIES EXPERIMENT STATION.

1946. Experimental pole and line fishing for skipjack.

Prog. Rpt. Kumamoto Pref. Fish. Expt. Sta. for 1942,

1943, 1944, pp. 3-5. [J] [P]

Ryukyu Islands ; skipjack fishing conditions corre-
lated with water temperature.

BIBLIOGRAPHY ON PACIFIC TUNAS

15

KUNfATA, T., BTT AL.

1!I41. Illustrated atlas of edible marine animals and
plants of the South Seas. Nissan Fish. Kes. Sta.,
Odawara, pp. 62-G5. [J]

Ktitfiuiconus V a g a n s, Xeothuntius macroittnus,
Parathunnus mehachi: distribution; English and
Japanese common names ; fisures : Dutch and Ma-
layan common names of li. macroptcrus and P.
mehachi

KfROXUMA, KATSUZO.

1940. A young of ocean sunfish, Mola nioln. taken from
the stomach of Germo yprmo, and a specimen of
Masturus Janccolatus as the second record from Jap-
anese waters. Bull. Biogeog. Soe. Japan, vol. 10, No.
2, pp. 2ij-28. [JE]

Stomach contents of Oermo germo noted.

IjACEPfeDE. Bernard Gebmaine Etienne.

1829. Histolre naturelle des poissons. Tome III. In:
Oeuvres du C!omte de Lac^iiede. Vol. 7, pp. 278, 285-
320. Paris. [C]

Lesson, Ren^ Pkimev{:re.

1S30. Voyage autour du monde, exfcut^ par order du
roi, sur la corvette de sa majeste. "La Cocinille",
pendant les ann^es 1S22, 1823, 1824, 1825. Zoologie,
vol. 2, pt. 1, pp. 162-166. Paris. [C]

Thynnus varans: description ; distribution ; figuied.

Lord, Clive.

1927. A list of the fi.shes of Tasmania. Jour. I'an-Pacific
Res. Inst., vol. 2, No. 4, p. 15.
Auxis thaeard, Tliunmis maceoyi: listed.

Lutken, Christian Frederick.

1880. Spolia Atlantica. Vidensk. Selskr. Skr.. 5 Ser.,
vol. 5, No. 11, pp. 460-483, 59.5-597 (Fi-ench resume).

Classification and synonymy of Orcytius spp. and
TInnuius spp. ; juveniles of O. germo described and
figured.

Macleat, William.

1881. Descriptive catalogue of Australian fishes, vol. 1,
pp. 191-192. Sydney. [C]

Thynnus affiinx, T. maceoyi, T. priamti.i: descrip-
tion ; distribution.

Manter, Harold W.

1940. Digenetic treraatodes of fishes from the Galapagos
Islands and the neighbouring Pacific. A. Hancock
Pacific Exised., vol. 2, No. 14, p. 448.

Oymnosarda aUctterata and G. peUimis listed as
hosts.

Marr, John C.

1948. Observations on the spawning of oceanic skipjack
(Kdtxiiwoniis prhimis) and yellowfin tuna (Nrothun-
niix marropirr)i.f) in the Northern Marshall Islands.
U. S. Fi.sh and Wildlife Serv. Fish. Bull., vol. 51, No.
44, pp. 201-206.

Kdimtironug pcla/inis: Marshall Islands; records

and descriptions of juveniles ; ova measurements.

K. pelamis, Ncothuniiiis macroptcrus: spawning;

length, sex. maturity data.

920179°— 51 2

Mark, John C, and Milner B. Schaefee.

1949. Definitions of body dimensions used in describ-
ing tuna.s. U. S. Fish and Wildlife Serv. Fi.sh. Bull.,
vol. 51, No. 47, pp. 241-244.
Martin, Claro.

193S. Tuna fishing and long-line fishing in Davao Gulf,
Philippines. Philippine Jour. Sci., vol. 67. No. 2. p.
189.
Katsutvonus pelamis, Neolhunnus iiosibi, N. mac-
ropterus: listed in commercial catch.
.Marikawa, Hisatoshi.
1939. Fisheries of the South Sea Islands: Natural food
of skipjack and tunas. South Sea Fish., vol. 5, No.
7, pp. 12-14. [J] [P]

Yellowfin tuna: stomach contents; juveniles of
Auxis Ihasard, Katsuwonus pelamis, and Parathun-
nus sibi mentioned as food of tunas.

MaTSIBARA. KlTOMATStl.

1943. Southern fishes. Formosa Fish. Mag., No. 334, pp.
11-14. [J] [P]

Albacore, big-eyed tuna, black tuna, yellowfin tuna :
South Seas ; distribution ; yellowfin tuna : descrip-
tion : skipjack : distribution ; migration ; sexual ma-
turity in Indo-Pacific region ; size difference between
South Seas and Japanese skipjack.
Matsui, Kizo.

1942a. Growth, water and fat content of the brain of
skipjack and tuna. South Sea Sci., vol. 5, No. 1, pp.
106-116. [J] [P]

Skipjack and yellowfin tuna.
194211. On the gonads of skipjack from the adjacent
waters of Palau. South Sea Sci., vol. 5, No. 1, pp.
117-122. [J] [P]

Gonad weight used as a criterion of sexual matu-
rity : gonads figured.
Matsusioto, Takeshi.

1937. An investigation of the skipjack fishery in the
waters of Woleai Island. South Sea Fish. News, No.
3, pp. 2-4. [J] [P]

Release of tagged skipjack recorded; migration.
McCt'i.i.ocH, Alan R.

1922. Check list of the fishes and fish-like animals of
New South Wales. Part III. Australian Zool., vol. 2,
pt. 3, pp. 104-105.

Auxis ramjiayi. A. thaeard, Eufhynnus alletterata,
E. pelamis, Thunnus germo, T. maceoyi: listed;
synonymy; key; figures of A. thazard, E. pelamis,
and T. maceoyi.

Meek. Seth E., and Samuel F. Hildf.brand.

1923. The marine fishes of Panama. Part I. Publ.
Field Mus. Nat. Hist., vol. 15, No. 215. pp. 314-316.

Auxis thazard, Germo alalunga, Gymnosarda alle-
terata, O. pelamis, Thunnus thynnus: description;
distribution; key: synonymy.
Metz, Charles Wilson.

1912. The fishes of Laguna Beach, Calif. I. Ann. Kpt.
Laguna Marine Lab., vol. 1, p. .32. [C]
Germo alalunga, Thunnus thunnus: recorded.

16

FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE

MiE Prepectural Fisheries Experiment Station.

1930a. Investigation of skipjacli fishing grounils and
guidance in fishing. Prog. Rpt. Mie Pref. Fish. Expt.
Sta. for 1027, pp. 1-15. [J] [P]
Japan ; skipjaclv fishing conditions correlated with
water temperatures and specific gravity.
1930b. Skipjack fishing and oceanographic conditions.
Prog. Rpt. Mie Pref. Fish. Expt. Sta. for 1927. pp.
15-17. [J] [P]

Japan ; skipjack fishing conditions correlated witli
water temperature and specific gravity.
19.30c. Investigation of tuna fishing grounds and guid-
ance in fishing. Prog. Rpt. Mie Pi'ef. Fish. Expt. Sta.
for 1927, pp. 18-33. [J] [P]

All)acore, big-eyed tuna, black tuna, yellowfln tuna :
Japan ; fishing conditions correlated with water
temperature and specific gravity.
1930d. Investigation of skipjack fishing grounds and
guidance in fishing. Prog. Rpt. Mie Pref. Fish. Expt.
Sta. for 1928, pp. 1-18. [J] [P]
Japan ; skipjack fishing conditions correlated with
water temperature and specific gravity.
1930e. Investigation of tuna fishing grounds and guid-
ance in fishing. Prog. Rpt. Mie Pref. Fish. Expt. Sta.
for 1928, pp. 19-33. [J] [P]

Albacore, big-eyed tuna, black tuna, yellowfin tuna :
Japan ; fishing conditions correlated with water
temperature and specific gravity.
MiGiTA, M., and K. Arak.\wa.

1948. Melanophorhormone of fishes. Contrib. Cent.
Fish. Expt. Sta. Japan (1946-1948), No. 39, pp. 241-
244. [Je]

Frigate mackerel, skipjack, Thiiniius orient alls,
yellowfin tuna : melanophorhormone content of
pituitary glands tabulated ; proportional weights of
various parts of T. oricntalis brain ; brain of yellow-
fin tuna figured.
Mine, Tatsdzo, and Satoku Iehisa.

1940. Appearances of the groups of Tlmnnus oricntalis
(T. and S.) in the seas south of Kyushu. Bull. Japa-
nese Soc. Sci. Fish., vol. 8, No. G, pp. 292-294. [Je] [P]
Size composition of commercial catch.

MiYAMA, YOSHIMICHI, and ISAMU OSAKABE.

1938. On the character of the fats obtained from the
various bodily parts of fishes. Bull. Japanese Soc.
Sci. Fish., vol. 7, No. 2, pp. lO.j-106. [Je] [P]

Kutsiiwoniis vaijnitn. Pardthunnus sibi, Thininiis
orientalis: chemical analysis of fats.
194f). Note on the vitamin oil contained in the liver of
fishes. Bull. Japanese Soc. Sci. Flsli., vol. 9, No. 1,
pp. 16-20. [Je] [P]

Big-eyed tuna, black tuna, skipjack, yellowfin tuna :
chemical analysis of liver and liver oil.
MiTAMA, YOSHIMICHI, KuMAN Saruya, and Takayoshi
Hasegawa.

1939. On the characters of the fats obtained from vari-
ous body parts of fi.sh. III. Bull. Japanese Soc. Sci.
Fish., vol. 8, No. 4, pp. 18.5-186. [ Je] [P]

Tlmnnus macroptcrus: South Seas; chemical analy-
sis of various body parts ; length-weight data, sex,
and stomach contents of specimens recorded.

Miyauchi, Saichi.

1915. Chemical studies of the dark lateral muscle. Proc.
Sci. Fish. Assoc, vol. 1, No. 1, pp. 38-49. [J]
Albacore, big-eyed tuna, black skipjack, black tuna,
skipjack: chemical analyses of flesh and dark
muscle.

Mori, Tamezo.

1928. A catalogue of the fishes of Korea. Jour. Pan-
Pacific Res. Inst., vol. 3. Xo. 3, p. 5. [Je]
Auxis thazard, Thminiis orientalis: listed.

Nakamura, Hiroshi.

1935. t'ber intersexualitiit bei Katsiiironus pelnmis
(Linn.). Trans. Nat. Hist. Soc. Formosa, vol. 25,
No. 141, pp. 197-198. [J]

Example of hermaphroditism recorded and de-
scribed.

1936. On the food habits of yellowfin tuna, Neofhnmuis
macroptcrus (Schlegel), from the Celebes Sea. Trans.
Nat. Hist. Soc. Formosa, vol. 2S, No. 148, pp. 1-8.
[J] [P]

Analyses of stomach contents ; length-weight data.
1938. Preliminary report on the habits of tlie black tuna,

Thumuis orientalis ( Schlegel ) . Zool. Mag., vol. 50, No.

5, pp. 279-281, pis. 1-8. [J] [P]

Description and figure of matui-e egg; gonads fig-
ured : distribution ; sexual maturity ; spawning
areas and season.
1939a. Notes on the differences between Neothunnus

macroptcrus and Neothunnus itosiii. Formosa Fi.sh.

Mag., No. 288, pp. 27-.32. [J] [P]

Neothunnus macroptcrus: classification; niorpho-
metric data ; synonymy ; Neothunnus compared with
Semathiinnus.
1939b. Report on the investigation of Thunnidae in

Formosan waters. Formosa Govt.-Gen. Fish. Expt.

Sta. Publ., No. 13, pp. 1-15. [Je] [P]
Auxis hira, A. maru, Eiitlii/nnus yaito: classifica-
tion; Japanese common names; synonymy. Katsu-
wonus pclaniis, Kishinoclla rara, Neothunnus
macroptcrus, Parathunnus mchachi, TItunnus germo,
T. 0)v'e«<a/is; classification ; description; distribu-
tion; synonymy; Japanese common names; figures
of all except N. macroptcrus, P. mehacM, and T.
germo. N. macroptcrus: spawning; morphometric
data ; compared externally with N. itosihi and Sema-
thiinnus gitildi. K. rara compared externally with
K. xacalles; spawning of 2'. orientalis.
1941. On the body temperatures of s(mie species of

Thunnidae and Istiophoridae. Proc. Sci. Fish. Assoc.,

vol. 8, No. 3, 4, pp. 25G-263. [J] [P]

Yellowfin tuna : Formosa ; body temperatures cor-
related with water temperatures.
1943. Tunas and spearfishes. Sci. Sea., vol. 3, No. 10,

pp. 445^59. [J]

Neothunnus macroptcrus, N. rarus, Parathunnus
mebaohi, Thunnus germo, T. orientalis: classifica-
tion ; distribution ; food ; Japanese common names ;
migration ; spawning.

BIBUOGRAPHY ON PACIFIC TUXAS

17

NAKAMfRA. HlROSHI — CoiltilUlod

1940. Tunas and tuna fishing. Takeuehi Bookstore.
Tokyo, April, 194',), lis pp. (JJ [I']

Oermo gcrmo, Ncathunnui macroptcni.i. .Y. ninis,
Paratliunnus mcbachi, I'hunnus oricntalis: bibli-
ography ; anatomy ; classification ; description ;
distribution; food; habits; keys; figures; Japanese
common names ; synonymy ; migration of G. gcrmo
and T. oricntnlia ; spawning of .V. macropicrux,
T. orientalis; description of T. orioitalis eggs; O.
ffcrmo, y. macrupti rus, P. mehachi; catch per unit
of effort ; fishing conditions in relation to ocean-
ography.

Nakamiira Research Stafi-.

1940. Report of the investigation of skipjack and tuna
resources. Cent. Fish. Expt. Sta. Rpt., No. 1 (for
1947), 7 pp. [J]

Katsuwonus pclamis: Japan; morphometrie data;
counts of meristic characters ; size composition
and sex ratio of commercial catch ; sexual maturity ;
stomach contents ; gonad weights ; egg counts.

Nichols, John Treu.dwell. and Francesca R. LaJIonte.
1041. Yellowfin, Allison's and related tunas. Ichth.

Contrib. Internatl. Game Fish Assoc, vol. 1, No. 3,

pp. 27-32.

Neothunmis albacora, X. alUsoni, N. catalinae, N.
rarus; classification; description: English common
names ; key ; synonymy ; provisional subspecies,
\cothiinnus aJbnrara athncora, N. alhacora ma-
cropterus, N. alUsoni allisani, N. allisoni itosibi,
and A'', rarus zacalles, proposed.

Nichols, John Teeadwell, and Robeet Cttshman
Murphy.
1922. On a collection of marine fishes from Peru. Bull.
American Mus. Nat. Hist., vol. 46, art. 0, pp. 503, 507.
Gcrmo arrjcntirittattis: Peruvian common name;
description.
1944. A collection of fishes from the Panama Bight,
Pacific Ocean. Bull. American Mus. Nat. Hist., vol.
83, art. 4, p. 240.

Katsuwonus pdumis: listed.

OiTA Prefectural Fi.siieries Experiment Station.
1925. Experimental tuna fishing. Prog. Rpt. Oita Pref.
Fish. Expt. Sta. for 1924, pp. 37-106. [J] [P]
Albacore, big-eyed tuna, skipjack, yellowfin tuna :
Ryukyu Islands: morphometrie data.
1927a. Experimental tuna fishing. Prog. Rpt. Oita Pref.
Fii?h. Expt. Sta. for 1925, pp. 1-56. [J] [P]
Albacore, big-eyed tuna, black tuna, yellowfin tuna :
Ryukyu Islands ; morphometrie data ; body tem-
peratures correlated with water temperature.
1927b. Exijerimental longline fishing for tuna. Prog.
Rpt. Oita Pref. Fish. Expt. Sta. for 1926, pp. 1-54.
[Jl [P]
Big-eyed tuna, yellowfin tuna: Ryukyu Islands;
morphometrie data.

Oita Prefectur.^l Fisheries Experiment Statio.v — Con.
1030. Report of experimental tuna fishing in the Kantfi
region. Prog. Rpt. oita Pref. Fish. Expt. Sta. for
1927. pp. 1-10. [J] [I'l

Big-eyed tuna, black tuna, yellowfin tuna : central
Japan : morphometrie data ; body temperatures cor-
related with water temperatures : fishing conditions
in relation to oceanography and weather.

Okada, Yakhiro, and Iviyomatsu Matsiib.^ra.

1038. Keys to the fislies and fish-like animals of Japan.
The Sauseido Co. Ltd.. Tokyo, pp. 140-l.-)(). [J]
Aiixis him, A. tnpcinosontn. Euthiinnux aUcttcnitun,
E. i/aito, Gcrmo pcrxio, Katsvwonus var/aiis, Kislii-
noella vara, Neothii7i>iiis itosibi, N. macroptcnis,
I'aratliunnus sibi, 'Jltunniis orientalis: classifica-
tion ; description ; distribution ; key ; Japanese com-
mon names.

Oka.moto, Gorozo.

1940. On the composition of shoals of "katsuo" Euthyn-
nus vagans (Lesson) in the northeastern Japanese
waters as anal.yzed by the body weight. Bull. Japa-
nese Soc. Sci. Fish., vol. 9, No. 3, pp. 100-102. [Je]
[P]
Size and age composition.

Okinawa Prefectur-ivl Fisheries Experiment Station.
1931. Investigation of the maturity of skipjack. Prog.
Rpt. Okinawa Pref. Fish. Expt. Sta. for 19.30. pp. 106-
107. [J] [P]

Skipjack length-weight data ; gonad weight and
maturity.
1940a. Experimental skipjack fishing. Prog. Rpt. Oki-
nawa Pref. P'ish. Expt. Sta. for 1939, pp. 3-5. [J]
[P]
Ryukyu Islands: skipjack catch correlated with air
and water temperatures.
1940b. Experimental tuna fishing. Prog. Rpt. Okinawa
Pref. Fish. Expt. Sta. for 19.30, pp. 6-8. [J] [P]
Bi.sr-eyed tuna, black tuna: Bonin Islands; catches
correlated with water temperature.
1943. Exijerimental skipjack fishing. Prog. Rpt. Oki-
nawa Pref. Fish. Expt. Sta. for 1941, pp. 4-14. [J]
[P]
Ryukyu Islands : distribution of skipjack : catch
correlated with air and water temperatures.

Okuda, Tuzuru.

191S. Some studies in marine chemistry. I'roe. Sci.
Fish. Assoc, vol. 2, No. 3, pp. 19,3-204, [J] [P]
Chemical analysis of dark muscle of frigate mack-
erel and skipjack.

Okuma, Yasvmichi, Kakt-ji iMAizr.Mi, and Juko Maki.

19.35. Investigation of South Sea fisheries by the Shonan

Maru : Investigation of tuna fishing grounds. Prog.

Rpt. Formosa Govt.-Gen. Fish. Expt. Sta. for 1933,

Fish. Sec, pp. 120-123. [J] [P]

Yellowfin tuna: Iiido-Pacific region; distribution;
stomach contents; length-weight data; sexual ma-
turity; fishing conditions in relation to oceanog-
raphy and weather ; catch per unit of effort.

18

FISHERY BULLETIN OF THE FISH ANiD WILDLIFE SERVICE

Omori. Kageyu, and Takeshi Fujimoto.
1940. Experimental longllne fishing for tuna. Prog.
Rpt. Nagasaki Pref. Fish. Expt. Sta. for 1938, pp.
175-214. [J] [P]

Big-eyed tuna, black tuna: .Japan; catches corre-
lated with water temperature and specific gravity.
O.MORI, Kageyu, and Mas^nobu Fukuda.

1938. Experimental longllne fishing for tuna. Prog.
Rpt. Nagasaki Pref. Fish. Expt. Sta. for 1936, pp.
47-^8. [J] [P]

Big-eyed tuna, bhick tuna: Japan; catches corre-
lated with water tempfrature and si>eclfic gravity.

1940. Experimental longllne fisliiiig for tuna. Prog.
Kpt. Nagasaki Pref. Fish. Expt. Sta. for 1937, pp. 45-
92. [J] [P]

Big-eyed tuna, black tuna: Japan; catches eoiTe-
lated with water temperature and specific gravity.

Onodera, Matsuji.

1941. The relation of freshness and condition factor of
Palau Islands skipjack to the ratio of finished prod-
ucts. South Sea Fish. News, vol. 5, No. 2, pp. 7-17.

[J] [P]

Skipjack length-weight data ; body condition of

fish.

Otaki, Keinosuke, Tsunenobu Fujita, and Tadashi

HlGFRASHI.

1903. Fishes of Japan; an account principally of eco-
nomic species. 1903-1904. Tokyo. [C]
Thunnus sohlegeli: Japan; figured.
Oya. Takeo, and Totoo Takahashi.

1936. On the growth accelerating substance in the liver
of the marine animals. Bull. Japanese Soc. Sci. Fish.,
vol. 5, No. 3, pp. 192-194. [Je] [P]
Growth hormones in skipjack livers.

Phillipps, W. J.

1927a. A check-list of the fishes of New Zealand. Jour.
Pan-Paciflc Res. Inst., vol. 2, No. 1, p. 14.
Eiithniniiig jH'lamis, Germo germon: listed.
1927b. Bibliography of New Zealand fishes. New Zea-
land Mar. Dept. Fish. Bull., No. 1, pp. 45-46.

Ocrino germo, Ealsuwonns pelamis, Thunmis phil-
lippsi: listed; classification; synonymy; New Zea-
land and Maori common names.
Phillips, W. J., and E. R. Hougkinson.

1922. Further notes on the edible fishes of New Zealand.

New Zealand Jour. Sci. Technol., vol. 5, No. 2, p. 93.

Oermo. germo, Gyiiinosarda pelamis: recorded.

Powell, A. W. B.

1937. Slarine fishes new to New Zealand ; including the
description of a new species of Halieutaea. Trans.
Roy. Soc. New Zealand, vol. 67. pt. 1, p. 80.
Neothunnns itosibi: recorded ; synonymy ; descrip-
tion ; figured.
Reeves, Cora D.

1928. A catalogue of the fishes of Northeastern China
and Korea. Jour. Pan-Pacific Res. Inst., vol. 2, No. 3,
p. 8.

Auxis tapeinogoma, A. thazurd, Katsuivoniis vagans,
Neothunnus niaeropterus, Thunnus oricntalis: listed.

Richardson, John.

1S40. Report on ichthyology of the seas of China and
Japan. Rpt. British Assoc. Adv. Sci., 15th meeting,
pp. 267-268.

Thynnus macroptenis, T. orientalis, T. pelamys, T.
sibi, T. tJninniiia: synonymy; distribution.

RoEDEL, Phil M.

1948a. Common marine fishes of California. California
Dlv. Fish and Game, Fish Bull. No. 68, pp. 59-63.
Kaf sine onus peJamis, Neothunnus niaeropterus,
Thunnus germo, T. thijnnus: classificatiou ; descrip-
tion; distribution; English common names; key;
figures; anatomical differences between I'arathun-
nus nicbachi and T. germo and between P. mebachi
and N. macropterus noted.
1948b. Occurrence of the black skipjack {Euthpnnus
lineatus) off southern California. California Fish
and Game, vol. 34, No. 1, p. 38.

Roughly, T. C.

1916. Fishes of Australia and their technology. Tech.
Edue. Ser., Technol. Mus. Sydney, No. 21, pp. 10, 162,
164-165.

Germo germo, Gymnosarda pelamis: distribution.
Thunnus maccoyi : classification; description; dis-
tribution; habits; figure.

Samson, V. J.

1940. Notes on the occurrence of albacore Oermo al-
alunga in the North Pacific. Copeia, No. 4, p. 271.

Sasaki, Takeo.

1939a. The relationship between oceanograpluc condi-
tions and skipjack fishing grounds in Northeastern
waters. Miyagl Pref. Fish. Expt. Sta., March, 1939,
12 pp. [J] [P]

Skipjack fishing conditions correlated with water
temperature ; migration ; size composition of schools.
1939b. The relationship between oceanographic condi-
tions and albacore fishing grounds east of Cape No-
jima. Miyagi Pref. Fish. Expt. Sta., April 1939, 14 pp.

[J] [P]

Albacore fishing conditions correlated with water
temperature ; migration ; size composition of schools.

SCAGEL, 11. F.

1949. Report on the investigation of albacore. Pacific
Biol. Sta., Fish. Res. Bd. Canada, Circ. No. 17, 23 pp.
Thunnus aUilunga: Northwest Pacific; catch corre-
lated with oceanographic conditions ; size composi-
tion of commercial catch; .stomach contents: tag-
ging; body temperatures.

SCHAEFER, MiLNER B.

194Sa. Morphometrlc characteristics and relative
growth of yellowfin tunas (Neothunnus maeropterus)
from Central America. Pacific Sci., vol. 2, No. 2, pp.
114-120.

Morphometrlc data; length-weight relationship:
growth ; classification based on variations in dorsal
and anal fin length discussed.

BIBLIOGRAPHY ON PACIFIC TUNAS

19

ScHAEFEB, MiLNER B. — Continued

1948b. Size composition of catches of yellowfln tuna
{Ncothunntts macroiiterus) from Central America,
and ttieir signiflcancp in the determination of growth,
age, and schoolini; liabits. U. S. Fish and Wldlife
Serv. Fisli. Bull., vol. 51, No. 44, pp. 107-200.

Size composition of commercial catch ; sexual ma-
turity ; age ; growth ; schooling habits ; length-
frequency data from mixed school of skipjaclc and
yellowfln tuna.
194,Sc. Spawning of Pacific tunas and its implications
to the welfare of the Pacific tuna fisheries. Trans.
Tliirteenth North Amer. Wildlife Conf.. pp. 3Clj-.S71.
Au.iiti sp., i:utli!iiinus Uncntiis, E. i/nito, Kntmi-
icniiKS pclaniix, ?i'eoihunnus macropteriis. Thiinnus
gerino: Pacific Ocean; distribution: review of rec-
ords and observations on spawning and juveniles ;
management problem.
ScHAF.FER. MiLNER B., and .7. C. Mark.

194^ia. Spawning of yellowfln tuna (Ncothminiis mn-
croptei-Kx) and sliipjaek {Kutsiiicoiuif! pdamis) in
the Pacific Ocean off Central America, with descrip-
tions of juveniles. U. S. Fish and Wildlife Serv. Fish.
Bull., vol. 51, No. 44, pp. 187-195.

\cof)iiiiituis macropterus: size composition in com-
mercial catch: sexual maturity; spawning. Katsu-
woniis pelamis: sexual maturity; .spawning; rec-
ords of capture, descriptions, and figures of N.
macropterus and K. pehimis juveniles.
1948b. Juvenile Eiiih!i))nus liiieatus and Atixix tluiznrd
from the Pacific Ocean off Central America. Pacific
Sci.. vol. 2, No. 4, pp. 262-271.
Anatomy, counts of meristic characters, descrip-
tion, figures, and records of capture of juveniles.
Schmidt, P.

1930. A check-list of the fishes of the Riu-Kiu Islands.
Jour. Pan-Pacific Res. Inst., vol. 5, No. 4, p. 3.
EHthynnus allcteratus: listed.
ScHMiTT, Waldo L.. and Leonard P. Schultz.
1940. List of the fishes taken on the Presidential Cruise
of 1938. Smithsn. Misc. Collect., vol. 98, No. 25, p. 3.
Eiithynnus aUcttcratus, E. lineatiis: listed and com-
pared.
ScHULTZ, Leonard P.
1949. .\ further contribution to the ichthyology of
Venezuela. Proc. U. S. Natl. Mus., vol. 99, pp. 1-211.
Tliiiiiniis thi/iniiix: listed; synonymy; English and
Venezuelan common names.
SCHULTz, Leox.\ed p., and Allan C. DeLacy.

1936. A catalogue of the fishes of Washington and
Oregon with distrilnitional records and a bibliog-
raphy. Mid-Pacific Mag., vol. 49, No. 1, pp. 70-71.
(Icnno alali(iif/n. ThioiniDs thynntis: synonymy;
distributional records.
Se.\le, Alvin.

1940. Report on fishes from Allan Hancock Expp<Utions
in the California .\cademy of Sciences. A. Hancock
Pa(ifi<' Kxped., vol. 9. No. 1. pp. 17-18.

EiitlniniiHs lincdtiis, Katsiiii-oinis prlawis, Neo-
thinniK.f macropterus: description; records of
capture.

Ser\e.ntt, D. L.
1941. Tlie Australian tunas. Council Sci. and Indust.
Res., Australia, Pamphlet No. 104, pp. 1-48.

Anris tltnxiinl, EiitliynnuK ntlctteratus, Katsuiconus
pelairus, Kishinoclla toiiiK/ol, Neothunnus macrop-
teruK, Thunnus gcniio. T. maccoiji: distribution,
description, key, figures, Australian common
names ; size groups, migi-atiou, and spawning of T.
maceoyi; length-weight relationship, and internal
and external differences of K. tonyijol and T. mac-
coy! compared; livers (if K. toiif/yot and T. maceoyi
figured.
1942a. Notes on the economics of the northern tuna
{Kishiiioelln tonyyol). Jour. Council Sci. and In-
dust. Res., Australia, vol. 15. No. 2, pp. 94-100.

Distribution; feeding habits; stomach contents;
spawning.
1942b. The tuna Ki-ihinoclla toiiyfjol Bleeker in Aus-
tralia. Jour. Council Sci. and Indust. Res., Australia,
vol. 15, No. 2, pp. 101-112.

Distribution ; description ; ratios of various body
proiiortions ; internal anatomy ; synonymy ; com-
pared with Kishinoella zacallcs, Neothunnus rams,
TJuninus nicoJsoni, Thynnus tongyol ; figures of T.
tono'jol and Kixhinoettn tonygol; cranium of K.
tonggol figured.

1947. A report on commercial tuna trolling tests in
southeastern Australia. Jour. Council Sci. and In-
dust. Res., Australia, vol. 20, No. 1, pp. 1-16.

KatKuironus pelamis, Thunnus germo, T. maccoyii:
recorded in catch ; catch per unit of effort, and
size composition of T. maccoyii.

1948. AJIothuntius fallai a new genus and species of tuna
from New Zealand. Rec. Canterbury Mus., vol. 5,
No. 3, pp. 131-135.

Classification ; description ; morphometric measure-
ments ; internal anatomy of type specimen ; records
of specimens and occurrences ; compared with
Katsuwonidae ; type specimen, liver, gill rakers
figured.
Shapiro, Sidney.
194Sa. The Japanese tuna fislieries. SCAP Nat. Re-
sources Sec. Rpt. No. 104, 00 pp.

Katsuiconus pelamis, Neothunnus macropterus,
Thunnus germo, T. orirntalis: liibliography ; classi-
fication ; description ; distribution ; migration ;
food; habits; fishing conditions correlated with
oceanography ; figures ; Japanese common names.
1948b. Aquatic resources of the Ryukyu area. SCAP
Nat. Resoui-ces Sec. Rpt. No. 117. 54 pp.
Au^vis hira, A. tapeinosoma, Euthynnns yaito, Kat-
suwonus pelamis, Neothunnus macropterus, Para-
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bibliography ; distribution ; Ryukyuan conmion
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SnlMAMfR.^, Kanae.

■1927. On the correlation between skipjack catch and
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No. 12, pp. 196-198. [J] [P]

20

riSHEKT BULLETIN OF THE FISH AND WILDLIFE SERVICE

SHI^rIzu, Wataru.
1947. Seasonal changes in the composition of tuna flesh.
Bull. Japanese Soc. Sci. Fish., vol. 13, No. 1, pp.
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Chemical analysis of black tuna flesh.

Shizuoka Peefectural Fisheries Experiment Station.

1936. Investigation of skipjack fishing. Prog. Rpt.
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[J] [P]
Skipjack catch correlated with water temperature.

1937. Investigation of skipjack fishing. Prog. Rpt.
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[J] [P]
Skipjack catch correlated with water temperature.

Smith, Osgood R., and Milner B. Schaefer.

1949. Fishery exploration in the western Pacific (.Janu-
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Big-eyed tuna, Eiitluiiinus yaito, KatsuH-onns pcla-
mis, yellowfin tuna : Hawaiian, Line, former Japa-
nese mandated islands; occurrence recorded; E.
yaito, K. pelamis figured.

Smith, Robert O.

1947. Survey of the fisheries of the former Japanese
mandated islands. U. S. Fish and Wildlife Serv., Fish.
Leaf. 273, pp. 89-95.
Katiiiiwonus pelamis. Neothminus macropterus,
Thnniu(s f/ertno: Hawaiian and Micronesian com-
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Snyder, John Otterdein.

1904. A catalogue of the shore fishes collected by the
steamer Albatross about the Hawaiian Islands in
1902. Bull. U. S. Fish Comm. for 1902, vol. 22, p. 523.
Germo sibi: recorded.

Society for the Promotion of Oceanic Fisheries.
1936. Tunas. Ocean. Fish., No. 4, pp. 1-62. [J] [P]
Albacore : differences in quality of flesh of summer
and winter fish correlated with sexual maturity,
body condition, season ; chemical analysis of fiesh ;
spawning : migration : location of fishing grounds
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compared with Thiinnus ihuntms; .spawning.

Soldatov, V. K.

1929. A check list of fishes recorded from Russian Pa-
cific waters. Jour. Pan-Pacific Res. Inst., vol. 4, No. 1,
p. 5.

Auxis thazard, Tliunnus thynnus: listed.

Soldatov, V. K., and G. J. LiNDRtniG.

1930. A review of the fishes of the seas of the Far East.
Bull. Pacific Sci. Fish. Inst., vol. 5, pp. 103-109.

Auxis Itira, A. mnru, Ocrmo alahiiifin. Kritsincoinia
pelamis, Jfeothunnus macropterus, Thunnus thyn-
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synonymy; keys to Parathunnus and Kishinoella;
Thunnus thynnus figured.

South Seas Government-General Fisheries Experiment
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1937a. Investigation of the fisheries of the Mariana
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1937b. Investigation of the fisheries of the Jlarshall
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I>istribution of tunas.
19.37c. Survey of fishing grounds and channels in Patau
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Skipjack fishing conditions correlated with oeeano-
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1938. Report of oceanographical investigations. South
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1941a. Experimental tuna fishing in waters adjacent to
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Distribution of tunas.
1941b. Investigation of tuna fishing in waters adjacent
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Indo-Pacific region ; yellowfin tuna catch correlated
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1941c. Investigation of skipjack fishing in the central
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Release of tagged skipjack recorded.
1941d. Investigation of skipjack fishing in Tap waters.
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Skipjack length-weight data ; body condition.
1942. Report of a survey of the tuna fishery in Palau
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1943a. Investigation of albacore fishing in the central
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Length-weight, body depth data for albacore and
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1943b. Report of the investigation of tuna fishing in
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Skipjack, yellowfin tuna : fishing conditions corre-
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Starks, Edwin Chapin.
1918. The mackerel and mackerel-like fishes of Cali-
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BIBUOGRAPHY ON PACIFIC TUNAS

21

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22

FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE

Taranetz, a. R.

1937. Handbook for identification of fishes of Soviet
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Auxis hira, A. inaru, Oermc alalunga, Katsuwonus
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tliunnina; figures of all except T. orientaUs; T.
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Thompson, William F., and Elmer Hiogins.

1919. Notes from the State Fisheries Laboratory. Cali-
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Auxis thazard noted in commercial catch ; distribu-
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1944. Hawaiian fishes. Tongg Publ. Co., Honolulu, pp.
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Auxis thaxard, Euthynnus allettcrntus, E. pelanii^,
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Hawaiian common names of E. aUetteratus, E.
peJamis, N. macropterus, T. thynnus; Japanese
common names of N. macropterus, 8. itosibi, T.
orientaUs, T. thynnus; European common names
of G. alalunga, T. thynnus; habits, food, enemies of
E. pelamis; food, enemies, reproduction of T.
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TiRANT, Gilbert.

1929. Note sur les poissons de la Basse-Cochinchine et
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TOMINAGA, SEIJIRO.

1943. Bonitos. Sci. Sea, vol. 3, No. 10, pp. 460-465. [J]
Frigate mackerels, black skipjack : description ;
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Tomitama, Tetsuo.

1933. The chemical composition of tunny liver oiL Bull.
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Toyama, Yuzo, et al.

1941. Studies on fish in Japan as a source of insulin.
Bull. Japanese Soc. Sci. Fish., vol. 10, No. 4.

Oermo germo, Katsuwonus vagans, Neothunnus
7nacroptems, Parathunnus sibi: yields of insulin
tabulated.
Tube, J. A.

1948. Whale sharks and devil rays in North Borneo.
Copeia, No. 3, p. 222.
Euthynnus macroptera: recorded.

UCHIDA, KEITAEO.

1923. On the jumping and flight of fishes and other
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Euthynnus vagans, Thunnus thynnus: jumping be-
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Uda, Michitaka.

1932. On the body weights of some scombroid fishes of
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Thunnus thynnus: probable causes of seasonal
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1935a. On the estimation of favourable temperature for
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Oermo macropterus, Parathunnus sibi, Thunmis
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1935b. The results of simultaneous oceanographical in-
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1936. Locality of fishing centre and shoals of "katuwo"
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BIBLIOGRAPHY OX PACIFIC TUNAS

23

Uda. Michitaka— Continued

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1937. Fishing of Oermo genno (Lac^i^^de) in relation
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1934. Local variations in the composition of various

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1940. The Acanthocephala collected by the Allan Han-
cock Pacific Expedition, 1934. A. Hancock Pacific
Exped., vol. 2, No. 15, p. 512.

Euthynnus altettcratus and Katsuwonus pelamis
listed as hosts.

Wade, Charles B.
1940. Notes on the Philippine frigate mackerels, family
Thunuidae, Genus Auxis. U. S. Fish and Wildlife
Serv. Fish. Bull., vol. 51, No. 46, pp. 22&-240.
Auxis tapcinosoma, A. thaxard: classification; de-
scription; key; synonymy; distribution; moi-pho-
metric measurements; counts of meristic charac-
ters; figures; records, descriptions, and figures of
juveniles.

Waite, Edgar R.

1907. A basic list of the fishes of New Zealand. Rec.
Canterbury Mus., vol. 1, No. 1, p. 24.
Oymnosarda pelamis: synonymy.
1921. Illustrated catalogue of the fishes of South Aus-
tralia. Rec. South Australian Mus., vol 2 No 1 p
143.

Tliunnus thynnus: listed; synonymy.

24

FISHERY BUXiLETIN OF THE FISH AJSTiD WILDLIFE SERVICE

Waitk, Edgar R. — Continued
192S. A catalogue of the marine fishes of South Aus-
tralia. Jour. Pan-Patiflc Res. lust., vol. 3, No. 1,
p. 8.

Thunnus maccori: listed.

Walford, Lionel A.

1931. Handbdolj of common commercial and game fishes
of California. California Dlv. Fish and Game, Fish
Bull. No. 28, pp. 74-77.

Germo alalunya, Kat silicon us pclaiiiis, Ncothiinniis
macropterus, Thunnus thynnus: classification; Eng-
lish common names : description ; distribution ;
figures ; ke.v.
1037. Marine game fishes of the Pacific Coast — Alaska
to the Equator. Univ. California Press, Berkeley, pp.
1-20, 2(>-30.

Euthjinnus Uncutus, Gcnno alaUinya, Katsxnconus
pelamis, Neothunnus macropterus, Thunnus thyn-
nus: description; distribution; food; spawning;
key ; English common names ; figures. Auxis
tha~ard: description ; distribution ; English common
names; figure; key. Migration of G. nJatunga, K.
pelamis and N. macropterus ; enemies of T. thyn-
nus; N. macropterus compared with Allison's tuna.
Wataxabe, Hajime.

1030. Investigation of albacore. Prog. Rpt. Shizuoka
Pref. Fish. Espt. Sta. for 10.36-38, pp. 22-23. [J] [P]
Albacore : mid-Pacific ; stomach contents ; sexual
maturity ; body proportions of males and females
compared ; morphometric data ; probable spawning
season, area, number of eggs.
Watanaee, Hakuo.

1940. Fishing conditions south of the Mar.shall Islands.
South Sea Fisli., vol. 6, No. 4, p. 22. [J] [P]
Big-eyed tuna, yellowfin tuna : length-weight data.
Wataxabe, N.

1041. Measurements on the bodily density, body temper-
ature and swimming-velocity of "katsuwo", Euthyn-
nus vaguns (Lesson). Bull. Japanese Soc. Sci.
Fish., vol. 11, No. 4, pp. 14C-14S. [Je]
Weber, Max.

1913. Die Fische der Siboga-Expedition. P. 401.
Leiilen.

Thynnus thunnina: Indo-Australian Archipelago;
synonymy ; recorded.

Welsh, James P.

1040. Range extension of the file fish Monocnnthus
mehDiocepIialus. Pacific Sci., vol. 3. No. 1, p. lOO.
Hawaii ; specimens recovered from Euthynnus
yaito.
Whitehead, S. S.

1920. Tuna season. California Div. Fish and Game,
Fi.sh Bull. No. 1.5, p. 48.

Albacore, bluefin tuna, skipjack, yellowfin tuna :
distribution and seasonal occurrence.
1931. Fishing methods for the bluefin tuna I Thunnus
thynnus) and an analysis of the catches. California
Div. Fish and Game, Fish Bull. No. 33, 32 pp.

Classification; distribution; figure; migraticm;
spawning; catch per unit of effort.
Whitley, Gilbert P.

1928. A check-list of the fishes of the Santa Cruz Archi-
pelago, Melanesia. Jour. Pan-Pacific Res. Inst., vol. 3,
No. 1, p. 12.

Neothunnus macropterus: listed.
1937. The Middleton and Elizabeth Reefs, South Pacific
Ocean. Australian Zool., vol. 8, pt. 4, pp. 229-231.
Wanderer wallisi proposed as new genus and
species ; synonymy ; description ; food ; compared
with E. yaito and E. allitfcratus.

1947. New sharks and fishes from Western Australia.
Australian Zool., vol. 11, pt. 2, pp. 129-150.

Euthynnus alleteratus, Katsuiconus pelamis, Kishi-
noclla tonggol, Neothunnus macropterus, Thunnus
maccoyi: recorded; Australian common names.
Yabe, Hiroshi. and Tokumi Mow.

1948. Report of .skipjack investigations for 1947. Cent.
Pish. Expt. Sta. Rpt., No. 30. [P]

Ryukyu Islands ; length-weight data ; stomach con-
tents ; catch correlated with water temperature ;
size composition of commercial catch ; age anal-
ysis ; spawning season ; maturation of gonads ; esti-
mated number of eggs ; past records of juveniles
captured in Ryukyu waters.
Yamamoto, Shokichi.

1940. Views on increasing the commercial value of dried

fish sticks from the South Seas. South Sea F^sh.,

vol. 3, No. 11, pp. 21-35. [J] [P]

Skipjack : Japan, Formosa, South Seas ; propor-
tional weights of various body parts compared.

ABBREVIATIONS USED

A. Hancock Pacific Exped. — Allan Hancock Pacific Ex-
peditions. Los Angeles.
Acad. Nat. Sci. Phila., Monogr. — Academy of Natural

Sciences of Philadelpliia, Monographs. Philadelphia.
Act. Soc. Sci. Indii-Nocrlandicae — Acta Societatis Scien-

tariiiin Indo-Ncerlandicae. Batavia.
Ann. and Mag. Nat. Hist. — The Annals and Magazine of

Natural History- Ix)ndon.
Ann. New York Acad. Sci. — Annals of the New York

Academy of Sciences. New York.
Ann. Rpt. Laguna Mar. Lab. — ^Annual Report of the

Laguna Marine Lalioratory. Claremont, California.
Annot. Zool. Jap. — Annotationes Zoologicae Japonenses.

Tokyo.
Arch. Neerlandaises Sci. Nat. — Archives Neerlandaises

des Sciences Exactes et Naturelles. Haarlem.
Australian Zool. — The Australian Zoologist. Sydney.

Bernice P. Bishop Mus. Occas. Papers — Bernice Pauahi
Bishop Jluseum. Occasional Papers. Honolulu.

Biblio. Nederlandsch Indische Nat. Ver. — Bibliotheek van
de Nederlandsch Indische Natuurhistorische Vereenig-
ing. Batavia.

Biol. Bull. St. John's Univ.— Biological Bulletin of St.
John's University. Shanghai.

Bull. American Mus. Nat. Hist. — Bulletin of the American
JInseura of Natural Historj. New York.

Bull. Bernice P. Bishop Mus. — Bulletin. Bernice Pauahi
Bishop Museum. Honolulu.

Bull. Biogeog. Soc. Japan — Bulletin of the Biogeographical
Society of Japan. Tokyo.

Bull. U. S. Bur. Fish.— Bulletin of tlie Bureau of Fish-
eries. United States Department of Commerce and
Lahor. Washington.

Bull. Japanese Soc. Sci. Fish. — Bulletin of the Japanese
Society of Scientific Fisheries. Tokyo.

Bull. Pacific Sci. Fish. Inst. — Bulletins of the Pacific
Scientific Fisheries Institute. Vladivostok.

Bull. Pacific Sci. Inst. Fish, and Oceanogr. — Bulletin of
the Pacific Scientific Institute of Fisheries and Ocean-
ograjihy. Vladivostok.

Bull. Scripps Inst. — Bulletin. Scripps Institution for
Biological Research. Berkeley.

Bull. So. Calif. Acad. Sci.— Bulletin of tlie Southern Cali-
fornia Academy of Sciences. Los Angeles.

Bull. U. S. Fish Comm.— Bulletin of the United States
Fi.sh Commission. Washington.

Bur. Fish., Min. .\gr. and For., Japanese Imp. Govt. —
Bureau of Fisheries. Ministi-y of Agriculture and For-
estry. Japanese Imperial Government. [Suisankyoku.
Norinsho. Dai Nippon Teikoku Seifu.] Tokyo.

California Div. Fish and Game, Bur. .Mar. Fish. — Cali-
fornia Division of Fish and Game, Bureau of Marine
Fisheries. San Francisco.

California I>iv. Fisli and Game, Fish Bull. — California
Division of Fish and Game. Fish Bulletin. Sacramento.

Cent. Fish. Expt. Sta. Rpt. — Central Fisheries Experiment
Station Reports. [Suisan Shikenjo Chosa HOkoku.]
Tokyo.

Com. Fish. Rev. — Commercial Fisheries Review. Fish
and Wildlife Sei-vice. United States Department of the
Interior. Washington.

Coiieia — Copeia. New York.

Council Sci. and Indust. Res., Australia, Pamphlet — Coun-
cil for Scientific and Industrial Research. Common-
wealth of Australia. Pamphlet. Melbourne.

Dept. Fish., New South Wales — Department of Fisheries,
New South Wales. Sydney.

Field Mus. Nat. Hist., Zool. Ser. — Field Museum of Natural
History, Zoological Series. Chicago.

Fish. Div., FAO, UN.— Fisheries Division. The Food and
Agriculture Organization of the United Nations. Wash-
ington.

Fish. Invest. (Suppl. Rpt.), Imp. FLsh. Expt. Sta. — Fishery
Investigation (Supplementary Report). Imperial Fish-
eries Experiment Station. Tokyo.

Fish. Res. Bd. Canada, Bull. — Fisheries Re.search Board of
Canada, Bulletin. Vancouver.

Fish. Technol. Lect. Series — Fisheries Technology Lecture
Series. [Suisan Seizo Kogaku Koza.] Tokyo.

Formosa Fish. Mag. — Formosa Fisheries Magazine. [Tai-
wan Suisan Zasshi.] Taihoku.

Formosa Govt.-Gen. Fish. Expt. Sta. Publ. — Formosa Gov-
ernment-General Fisheries Experiment Station. Publi-
cations. [Taiwan Sotokufu Suisan Shikenjo Shuppan.]
Kiirun.

Iclith. Contrlb. Internatl. Game Fish Assoc. — Ichthyologi-
cal Contriliutions of the International Game Fish Asso-
ciation. New York.

Japanese Jour. Zool. — Japane.se Journal of Zoology.

Tokyo.
Jour. Acad. Nat. Sci. Phila. — Journal of the Academy of

Natural Sciences of Philadelphia. Philadelphia.
Jour. Asiatic Soc. Bengal — Journal of the Asiatic Society

of Bengal. Calcutta.
Jour. Biol. Chem. — Journal of Biological Chemistry. New

York.
Jour. Coll. Agr., Imp. Univ. Tokyo — Journal of the Collesre

of Agriculture. Imperial University of Tokyo. Tokyo.
Jour. Coll. Sci., Imp. Univ. Tolcyo — Journal of the College

of Science. Imperial University of Tokyo. Tokyo.
Jour. Council Sci. and Indust. Res., Australia — Journal of

the Council for Scientific and Industrial Research.

Commonwealth of .\ustralia. Meltiourne.
Jour. Fac. Sci., Imp. Univ. Tokyo — Journal of the Faculty

of Science, Imperial University of Tokyo. Tokyo.

25

26

FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE

Jour. Imp. Fish. Bur. Tokyo — Journal of the Imperial
Fisheries Bureau. Tokyo.

Jour. Imp. Fish. Expt. Sta. — Journal of the Imperial Fish-
eries Experiment Station. Tok.vo.

Jour. Mus. Godeffroy — Journal des Museum Godeffroy.
Hamburg.

Jour. Pan-Pacific Res. Inst. — Journal of the Pan-Pacific
Research Institution. Honolulu.

Mem. Bernice P. Bishop Mus. — Jlemoirs of the Bernice
Pauahi Bishop Museum. Honolulu.

Mem. California Acad. Sci. — Memoirs of the California
Academy of Sciences. San FrancLsco.

Mem. Carnegie Mus. — Memoirs of the Carnegie Museum.
Pittsburgh.

Mid-Pacific Mag. — Mid-Pacific Magazine. Honolulu.

Miyagl Pref. Fish. Expt. Sta. — Miyagi Prefe<.tural Fish-
eries Experiment Station. [Miyagi-ken Suisan Shi-
kenjo. Watanoha.

Nat. Genee.sk. Arch. Neerland's Indie — Natuur en Genee-
skundig Archief voor Neerland's-Indie. Batavia.

Nat. Ti,idschr. Nederlandsch-Indie — Natuurkundig Tijd-
schrift voor Nederlandsch-Indie. Batavia.

Nederlundsch Tijdschr. Dierk. — Nederlandsch Tijdschrift
voor de DIerkunde. Amsterdam.

New Zealand Jour. Sci. Technol. — New Zealand Journal
of Science and Technology. Wellington.

New Zealand Mar. Dept. Fish. Bull. — New Zealand Marine
Department Fisheries Bulletin. Wellington.

Nissan Fish. Res. Sta. Odawara — Nissan Fisheries Re-
search Station. [Nissan Suisan Kenkyujo.] Odawara.

Note Serv. OciSanogr. Peches Indochine — Notes. Service
OcSanographique des Peches de ITndochine. Station
Maritime de Cauda. Saigon.

Occas. Pap. California Acad. Sci. — Occasional Papers of

the California Academy of Sciences. San Francisco.
Ocean. Fish. — Oceanic Fisheries. [Kaiyo Gyogyo.] Tokyo.

Pacific Biol. Sta., Fish. Res. Bd. Canada, Circ. — Pacific
Biological Stations, Fisheries Research Board of Can-
ada. Vancouver.

Pacific Sci. — Pacific Science. Honolulu.

Palao Trop. Biol. Sta. Studies— Palao Tropical Biological
Station Studies. Tokyo.

Philippine Jour. Sci. — Philippine Journal of Science.
Manila.

Proc. Acad. Nat. Sci. Phila. — Proceedings of the Academy
of Natural Sciences of Philadelphia. Philadelphia.

Proc. California Acad. Sci. — Proceedings of the California
Academy of Sciences. San Francisco.

I'roc. Sci. Fish. Assoc. — Proceedings of the Scientific Fish-
eries Association. Tokyo.

I'roc. Sixth Pacific Sci. Cong. — Proceedings of the Sixth
Pacific Science Congress. Berkeley and Los Angeles.

Proc. U. S. Natl. Mus. — Proceedings of the United States
National Museum. Washington.

Proc. Zool. Acclim. Soc. Victoria — Proceedings of the
Zoological and Acclimation Society of Victoria. Vic-
toria.

Prog. Rpt. Chiha Pref. Fish. Expt. Sta. — Progress Reports
of the Chiba Prefectural Fisheries Experiment Station.
[Chiba-ken Suisan Shikenjo Jigyd Hokoku.] Tateyama.

Prog. Rpt. Chiba Pref. Fish. Expt. Sta., Katsuura Br.—
Progress Reports of the Chiba Prefectural Fisheries
Experiment Station, Katsuura Branch. [Chiba-ken
Suisan Shikenjo Katsuura Bunjo Jigyo Hokoku.]
Katsuura.

Prog. Rpt. Formosa Govt.-Gen. Fish. Expt. Sta. — Progress
Reports of the Formosa Government-General Fisheries
Experiment Station [Taiwan Sotokufu Suisan Shi-
kenjo ; Jigyo Hokoku ; Shiken Hokoku ; Suisan Shiken
Hokoku.] Kiirun.

Prog. Rpt. Hokkaido Fish. Expt. Sta. — Progress Reports
of the Hokkaido Fisheries Experiment Station. [Hok-
kaido Suisan Shikenjo Suisan Chosa Hokoku.] Yoichi.

Prog. Rpt. Kagoshima Pref. Fish. Expt. Sta. — Progress
Reports of the Kagoshima Prefectural Fisheries Experi-
ment Station. [Kagoshima-ken Suisan Shikenjo Jigyo
Hokoku.] Kagoshima.

Prog. Rpt. Kochi Pref. Fish. Expt. Sta. — Progress Reports
of the Kdchi Prefectural Fisheries Experiment Station.
[Kochi-ken Suisan Sliikenjo Jigyo Hokoku.] Susaki.

Prog. Rpt. Kumamoto Pref. Fish. Expt. Sta. — Progress
Reports of the Kumamoto Prefectural Fisheries Experi-
ment Station. [Kumamoto-ken Suisan Shikenjo Jigyo
Hokoku.] Kumamoto.

Prog. Kpt. Mie Pref. Fish. Expt. Sta.— Progress Reports
of the Mie Prefectural Fisheries Experiment Station.
[Jlie-kon Suisan Shikenjo Jigyd Hokoku.] Tsu.

Prog. Rpt. Nagasaki Pref. Fish. Expt. Sta. — Progress Re-
ports of the Nagasaki Prefectural Fisheries Experiment
Station. [Nagasaki-ken Suisan Shikenjo Jigyo Ho-
koku.] Nagasaki.

Prog. Rpt. Oita Pref. Fish. Expt. Sta. — Progress Reports
of the Oita Prefectural Fisheries Experiment Station.
[Oita-ken Suisan Shikenjo GyOmu Hokoku.] Oita.

Prog. Rpt. Okinawa Pref. Fish. Expt. Sta.— Progress Re-
ports of the Okinawa Prefectural Fisheries Experiment
Station. [Okinawa-ken Suisan Shikenjo: Jigyd Ho-
koku; Seiseki ; Seiseki Gaiyd.] Naha.

Prog. Rpt. Pacific Coast Sta., Fish. Res. Bd. Canada— Re-
ports of the Pacific Coast Stations, Fisheries Research
Board of Canada. Vancouver.

Prog. Rpt. Shizuoka Pref. Fish. Expt. Sta. — Progress Re-
ports of the Shizouka Prefectural Fisheries Experiment
Station. [Shizuoka-ken Suisan Shikenjo Jigyd Ho-
koku.] Sliimizu.

Prog. Rpt. South Seas Govt.-(Jen. Fish. Expt. Sta.— Prog-
ress Reports of the South Seas Government-General
Fisheries Experiment Station. [Nanyd-chd Suisan
Shikenjo Jigyd Hokoku.] Patau.

Prog. Rpt. Taihoku Prov. Fi.sh. Expt. Sta.— Progress Re-
ports of the Tailioku Province Fisheries Experiment
Station. [Taihoku-shii Suisau Shikenjo Gydmu Hd-
koku.] Taihoku.

Prog. Rpt. Takao Prov. Fish. Expt. Sta. — Progress Reports
of the Takao Province Fisheries Experiment Station.
[Takao-shfi Suisan Shiken Chdsa Hokoku.] Takao.

Publ. Field Mus. Nat. Hist. — Puljlications. Field Museum
of Natural History. Chicago.

BIBLIOGRAPHY ON PACIFIC TUNASI

27

Rec. Canterbury Mnscuin — Records of the C;inlerliui-y -Mu-
seum. Christcliuieh.

Rec. Oceanogr. Works — Records of Oceauographic Works
in Japan. Tokyo.

Rec. So. Australian Mus. — Records of the South Australian
Museum. Adelaide.

Rpt. British Assoc. Adv. Sci. — Report of the Briti.sh As-
sociation for the Advancement of Science. London.

Rpt. U. S. Fish Conim. — Report of the Commissioner.
United States Commission of Fish -and Fisheries.
Washington.

SCAP Nat. Resources See. Rpt. — Supreme Commander for

the Allied Powers. General Headquarters. Natural

Resources Section. Reports. Tokyo.
Sci. Sea — Science of the Sea. [Kaiyo no Kagaku.]
Sea and Sky — Sea and Sky. [Umi to Sora.] Kobe.
Semi-Ann. Rpt. Oceanogr. Invest. — Semi-Annual Report

of Oceaniigraphical Investigations. Tokyo.
Smithsn. Misc. Collect. — Smithsonian Miscellaneous Col-
lections. Washington.
Soc. Prom. Ocean. Fish. — Society for the Promotion of

Oceanic Fisheries. [Kaiyo Gyogyo Kyokai.] Tok.vo.
South Sea Fish. — South Sea Fisheries. [Nanyo Suisau.]

Tokyo.
South Sea Fish. News — South Sea Fisheries News.

fNanyo Suisan JohO.] Patau.
South Sea Sci. — South Sea Science. [Kagaku Nanyo.]

Palau.
Stanford Ichth. Bull.— Stanford Ichthyological Bulletin.

Stanford.
Stanford Univ. Publ., Univ. Ser., Biol. Sci.— Stanford

University Publications, University Series, Biological

Sciences. Stanford.

Tecli. Educ. Ser. Technol. Mus., Sydney — Technical Edu-
cation Series. Technological Museum. Sydney.

Text Fish.— The Text of the Fisheiy. Tokyo.

Trans. Nat. Hist. Soc. Formosa — Transactions of the
Natural History Society of Formosa. [Taiwan Haku-
butsu Gakkai Kaiho.] Taihoku.

Trans. New Zealand Inst. — ^Transactions and Proceedings

of Ihe New Zealand Institute. Wellington.
Trans. Roy. Soc. New Zealand — Transactions and Proceed.

ings of the Royal Society of New Zealand. Dunedin.
Trans. Thirteenth No. Amer. Wildlife Conf. — Transactions

of the Thirteenth North American Wildlife Conference.

Washington.
Trav. Inst. Oceanogr. Indochine — Travaux de I'lnstitut

Oceanographique de I'Indochine. Saigon.
Treubia — Treubia. Buitenzorg.

U. S. Fish and Wildlife Serv., Circ- United States Depart-
ment of the Interior, Fish and Wildlife Service, Circu-
lar. Washington.

U. S. Fish and Wildlife Serv. Fish. Bull.— United States
Department of the Interior. Fishery Bulletin of the
Fish and Wildlife Service. Washington.

U. S. Fi.sh and Wildlife Serv., Fish. Leaf.— United States
Department of the Interior. Fish and Wildlife Service,
Fishery Leaflet. Washington.

U. S. Natl. Mus. Bull. — United States Naticmal Museum.
Bulletin. Washington.

Univ. California Publ. Zool. — University of California
Publications in Zoology. Berkeley.

Verb. Batavia Genoot. Kunst. Wetene. — ^Verhandelingen
van het Bataviaasch Genootschap van Kunsten en
Wetenschappen. Batavia.

Versl. Akad. Amsterdam — Verslagen van de Gewone
Vergaderingen der Wis en Natuurkundige Afdeeling.
Koninklijke Academic van Wetenschappen. Amsterdam.

Vidensk. Selskr. Skr. — Kongelige Danske Videnskabernes
Selskab. Copenhagen.

Woods Hole Oceanogr. Inst. Tech. Rpt. — Woods Hole
Oceauographic Institution. Technical Report. Woods
Hole.

Zool. Mag. — Zoological Magazine. [Dobutsugaku Zasshi.]

Tokyo.
Zool. Meded. — Zoologische Mededeelingen. Leiden.

INDEX BY SUBJECTS

Age

Aikawa, 1937.
Aikawa and Kato, 1938.
Ban, 1041.
Bi-ock, 1943.
Higashi, 1941b.

Ikebe, 1939, 1940a, 1940b, 1940c, 1941a, 1941b.
Kanamura and Yazaki, 1940a, 1940b.
Kimura, 1935, 1941, 1942a.
Okamoto, 1940.
Schuefer, 1948b.
Tauchi, 1940a, 1940b, 1940e.
Uno, 193Cb.
Tabe and Mori, 1948.
Albacore. See Tlmnnus germo.
Allison's tuna. See Neothunnus alHsoni.
Alloihunnus fallai
Anatomy

Serventy, 1948.
Classification

Fraser-Brunner, 1950.

Serventy, 1948.
Compared with Katsuwonidae

Serventy, 1948.
Description

Fraser-Brunner, 1950.

Serventy, 1948.
Distribution

Fra.ser-Brunner, 1950.

Serventy, 1948.
Figured

Fraser-Brunner, 1950.

Serventy, 1948.
Keys

Fraser-Brunner, 1950.
Measurement data

Serventy, 1948.
Synonymy

Fraser-Brunner, 1950.
Anatomy
Air bladder

Fish, 1948.

Kishinouye, 1922a.
And evolution

Kishinouye, 1919a.
Brain

Matsul, 1942a.

Migita and Arakawa, 1948.
Digestive system

Suyehiro, 19.36, 1938, 1941, 1942.
External and internal

Berg, 1947.

Eckles, 1949b.

Godsil and Byers, 1944.

Imamura, 1949.

28

Anatomy — Continued

External and internal — Continued

Kishinouye, 1915a, 191ub, 1917a, 1918, 1921, 1923.

Nakauiura, 1949.

Roedel, 1948b.

Schaefer and Marr, 194Sb.

Serventy, 1942b, 1948.

Takahashi, 1924.
Figured

Godsil and Byers, 1944.

Higashi, 1941a, 1941c.

Kishinouye, 1915b, 1919a, 1923.

Matsul, 1942b.

Migita and Arakawa, 1948.

Nakamura, 1938.

Serventy, 1941, 19421), 1948.

Suyehiro, 1942.
Reproductive system

Bennett, 1840.

Matsui, 1942b.

Nakamura, 1938.

Nakamura Res. Staff, 1949.

Okinawa Pref. Fish. Expt. Sta., 1931.
Astronomical phenomena correlated with filshing
Kawana, 1934.

Takao Prov. Fish. Expt. Sta., 1927.
Auxis
Anatomy

Kishinouye, 1915b, 1919a.
As food of tunas

Asano, 1939.
Chemical analysis

Okuda, 1918.
Common names

Tominaga, 1943.
Description

Tominaga, 1943.
Distribution

Schaefer, 1948c.

Tominaga, 1943.
Food

Tominaga, 1943.
Habits

T<miinaga, 1943.
Honnones

Migita and Arakawa, 1948.
Reproduction

Schaefer, 1948c.
Young

Kishinouye, 1926.

Schaefer, 1948c.
Auxis hira
Anatomy

Kishinouye, 1915a, 1923.

BIBLIOGRAPHY ON PACIFIC TUNAS

29

A axis hira — Continued
Classification

Kishinouye, lOina, 1923.

Nakaniura, 193'JI).

Olinda and Jlatsubaia, 1938.

Soldatov and Liudbers, 1930.

Taranetz, 1937.
Common names

Fujita and Wakiya, 1915.

Kishinouye, 19ir)a, 1923.

Nakamnra, 19;!91).

Okada and Mafsuliara, 1938.

Shapiro, 194Sb.
De.scription

Imamura, 1949.

Jordan and Hiibbs, 1925.

Kishinouye, 1915a, 1923.

Okada and Matsubara, 19.38.

Soldatov and Lindlierg. 1930.
Distribution

Fujita and Wakiya, 1915.

Imamura, 1949.

Jordan and Hubbs, 1925.

Kishinouye, 1915a, 1923.

Okada and Matsubara, 1938.

Shapiro, 194Sb.

Soldatov and Lindberg, 1930.

Tanaka, 1931.

Taranetz, 1937.
Figured

Kishinouye, 1915a, 1923.
Food

Kishinouye, 1923.
Habits

Imamura, 1949.

Kishinouye, 1923.
Keys

Kisliinouye, 1915a, 1923.

Okada and Matsubara, 1938.

Soldatov and Lindberg, 1930.

Taranetz, 1937.
Synonymy

Kishinouye, 1923.

Nakamura, 1939b.

Soldatov and Lindberg, 1930.

Tanaka, 1931.

Auxi.i maru
Anatomy

Kishinouye, 1915a, 1923.
Classification

Kishinouye, 191.5a, 1923.

Nakamura, 1939b.

Soldatov and Lindberg, 1930.

Taranetz, 1937.
Common names

Fujita and Wakiya. 1915.

Kishinouye, 1915a, 1923.

Nakamura, 1939b.

Aiixis maru — Continued
Description

Imamura, 1949.
Kishinouye, 191.".a, 1923.
Soldatov and Lindberg, 1930.
Distribution
Fujita and Wakiya, 1915.
Imamura, 1949.
Kishinouye, 191.-.a, 1923.
Soldatov and Lindberg, 1930.
Taranetz, 1937.
Figured

Kishinouye, 1915a, 1923.
Food

Kishinouye, 1923.
Habits

Imamura, 1949.
Kishinou.ve, 1923.
Keys

Kishinouye, 1915a, 1923.
Soldatov and Lindberg, 1930.
Taranetz, 1937.
Reproduction

Kishinouye, 1915a.
Synonymy
Kishinouye, 1923.
Nakamura, 1939b.
Soldatov and Liuillierg, 1930.
Young as food of tunas
Kishinouye, 1917b, 1923, 1924.
Auxis ramsayi
Distribution

McCulloch, 1922.
Keys

McCulloch, 1922.
Synonymy
McCulloch, 1922.
Atiwis rochei
Description

Giinther, 1860.
Distribution
Chu, 1931.
Giinther, 1860.
Synonymy
Chu, 1931.
Gunther, 1860.
Auxis tfiijcinosomti
Classification
Okada and Matsubara, 1938.
Wade, 1949.
Common names

Jordan and Hubbs, 1925.
Jordan and Snyder, 1!)01.
Okada and Matsubara. 1938.
Shapiro, 194.Sb.
Compared with Au.ri.s thyniioides

Bleeker, 1855.
Description
Bleeker. 1854.
Gunther, 1860.

30

FISHDRT BULLETIN OF THE FISH AKD WILDLIFE SERVICE

Auxis tapeinosoma — Continued
Description — Continued

Jordan and Hubbs, 1925.

Okada and Matsubara, 1938.

Wade, 1949.
Distribution

Bleelier. 18.54, 18.57.

Giinther, 1860.

Jordan and Hubbs, 1025.

Jordan and Snyder, 1001.

Okada and Matsubara, 1938.

Reeves, 1928.

Shapiro, 1948^

Wade, 1949.
Figured

Wade, 1949.
Keys

Okada and Matsubara, 1938.

Wade, 1940.
Measurement data

Wade, 1949.
Meristic characters

Wade, 1949.
Synonymy

Giinther, 1860.

Jordan and Hubbs, 1925.

Wade, 1949.
Young

Wade, 1949.
Auxis taso

Compared with Auwis thynnoides

Bleeker, 1855.
Description

Cuvier and Valenciennes, 1831.
Distribution

Bleeker, 1845, 1850, 1878.

Auxis thazard
Anatomy

Schaefer and Marr, 1948b.
As food of tunas

Marukawa, 1939.
Classification

Fraser-Brunner, 1950.
Common names

Barnhart, 1936.

FAO, 1949.

Fish, 1948.

Herre and Umali, 1948.

Jordan and Evermann, 1896.

Jordan and Metz, 1913.

Jordan, Tanaka, and Snyder, 1913.

Serventy, 1941.

Tinker, 1944.

Ulrey and Greeley, 1928.

Walford, 1937.
Description

Barnhart, 1936.

Cuvier and Valenciennes, 1831.

Fowler, 1928, 1938.

Fraser-Brunner, 10.50.

Auxis thazard — Continued
Description — Continued

Jordan and Evermann, 1905.

Meek and Hildebrand, 1023.

Schaefer and Marr, 1948b.

Serventy, 1941.

Tinker, 1944.

Wade, 1949.

Walford, 1937.
Distribution

Barnhart, 1936.

Domantay, 1940.

FAO, 1949.

Fish, 1948.

Fowler, 1928, 1938, 1944, 1949.

Fraser-Brunner, 1950.

Graham, 1038.

Herre, 1040.

Jenkins, 1003.

Jordan and Evermann, 1896, 1905.

Jordan and Jordan, 1022.

Jordan and Metz, 1013.

Jordan and Seale, 1906.

Jordan and Snyder, 1000.

Jordan, Tanaka, and Snyder, 1913.

Lord, 1927.

McCuUoch, 1922.

Meek and Hildebrand, 1923.

Mori, 1928.

Reeves, 1928.

Schaefer and Marr, 1948b.

Serventy, 1041.

Soldatov, 1929.

Stead, 1008.

Thompson and Higgins, 1919.

Tinker, 1944.

Ulrey, 1029.

Ulrey and Greeley, 1928.

Wade, 1049.

Walford, 1937.
Figured

Barnhart, 1936.

Domantay, 1940.

Fraser-Brunner, 1930.

Jordan and Evermann, 1905.

Jordan, Tanaka, and Snyder, 1913.

McCuUoch, 1922.

Schaefer and Marr, 1948b.

Serventy, 1041.

Tinker, 1044.

Wade, 1949.

Walford, 1037.
Keys

Brock, 1949.

Fraser-Brunner, 1950.

McCuUoch, 1922.

Meek and Hildebrand, 1923.

Serventy, 1941.

Wade, 1949.

Walford, 1037.

BIBLIOGRAPHY ON PACIFIC TUNAS

31

.1 »./-i.s thaznrd — Cnntimioa
Measurement data

Wade, 1949.
Meristic characters

Schaefer and Marr, 1948b.

Wade, 1949.
Synonymy

FAO, 1949.

Fowler, 192S, 19;'.S, 1944, 1949.

Fraser-Brunner, 1950.

Jenkins, 1903.

Jordan and Everniann, 1S96, 1905.

Jordan, Tanaka, and Snyder, 1913.

McCulloch, 1922.

Meek and HiUlebrand, 1923.

Ulrey and Greeley, 1928.

Wade, 1949.
Young

Schaefer and Marr. 1948b.

Wade, 1949.
Toung as food of tunas

Marukawa, 1939.
Anxis thyniw.ides

Compared with Aii.iix taiidnosoma

Bleeker, 18.55.
Compared with Auxis tnso

Bleeker, 1855.
Compared with Auxis mlgaris

Bleeker, 1855.
Description

Bleeker, 18.".5.
Distribution

Bleeker, 1855, 1863, lS65a.
Avxis vulgaris

Compared with Auxis thiiinioides

Bleeker, 1855.

Bibliography

Corwin, 19.30.

Kishinouye, 1923.

Nakamura, 1949.

Shapiro, 194Sa, 194Sb.
Big-eyed tuna. See Painthunnns spp.
Black tuna. See ThinniHS oricntalis.
Bluefin tuna. See TIiiiidiiis thiiiinus.
Body condition

Aikawa, 1937.

Aikawa an<l Kato, 1938.

Ikebe, 1939.

Ikebe and Matsumoto, 1937.

Kanamura and Yazaki. 194()a, 1940b.

Onodera, 1941.

Soc. Prom. Ocean. Fish., 1936.

South Seas Govt.-Gen. Fish. Expt. Sta., 1941d.

Suyehiro, 1936, 1938.
Body temperature

.Vnonynious, 19.38.

Kananuira and Imaizunii. 19.35.

Kanamura and Yazaki, 1940a, 1940b.
929179°— 51 3

Body liMiiiieralure — Continued

Nakamura, 1941.

Oita Pref. Fish. E.xpt. Sta., 1927a, 1930.

Scagel, 1949.

Uda, 1941.

Watanabe, N., 1941.
Bonito. See KutsKirnnus pclamia.

Cateli per unit of I'flfort

Formosa Govt.-Gen. Fish. Expt. Sta., 1933a.

Hiratsuka and Imaizumi, 1934.

Hiratsuka and Ito, 19.34.

Imaizumi, 1937.

Japanese Bur. Fish., 1939. 1940.

Kanamura and Imaizumi, 19:',.".

Kanamura and Yazaki, I'.iKia, 1940b.

Nakamura, 1949.

Okuma, Imaizumi, and Maki, 1935.

Serventy, 1947.

Whitehead, 1931.
Characters, meristic. See Morphometries.
Chemical analysis

Dill, 1921.

Higashi and Hirai, 1948.

Kodama, lizuka, and Harada, 1934.

Miyama and Osakabe, 19.38, 1940.

Miyama, Saruya, and Hasegawa, 1939.

Miyauchi, 1915.

Okuda, 1918.

Shimizu, 1947.

Soc. Prom. Ocean. Fish., 1936.

Tomiyama, 1933.
Classification

Berg, 1947.

Fraser-Brunner, 1949, 1950.

Godsil and Byers, 1944.

HiUlebrand, 1946.

Jordan, 1923.

Kishinouye, 1915a, 1917a, 1923.

Lacepede, 1829.

Liitken, ISSO.

Nakamura, 19.39a, 19.39b, 1943, 1949.

Okada and Matsubara, 1938.

Phillipps, 1927b.

Roedel, 194Sb.

Roughly, 1916.

Schaefer, 194Sa.

Serventy, 1948.

Shapiro, 1948a.

Soldatov and Lindberg, 19.30.

Takahashi, 1924, 1926.

Taranetz, 1937.

Wade, 1949.

Walford, 1931.

Whitehead, 1931.

Whitley, 1937.
Color, water. See Water color, also Oceanographic con-
ditions.
Condition, body. See Body condition.
Contents, stomach. .See Food.

32

FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE

Currents. See also Oceanographic conditions.
Correlated with fishing

Formosa Govt.-Gen. Fish. Expt. Sta., 1930, 1931, 1932,

laSSb, 1934.
Ikebe, 19-lOd.

Inanami, 1940b, 1940e, 1941.

Kagosliima Pref. Pish. Expt. Sta., 1927b, 1928a.
South Seas Govt.-Gen. Fish. Expt. Sta., 1942, 1943b.

Distribution
Abe, 1939.

Anonymous, 1938, 1941.
Barnhart, 1936.
Bleeker, 1844, 184.5, 1850, 1852, 1854, 1855, 1856, 1857,

1860a, 1860b, 1861a, 1861b, 1862, 1863, 1865a, 1865b,

1878, 1879.
Brock, 1938, 1939.
Cantor, 1850.
Chabanaud, 1926.
Chapman, 1946.
Chevey, 1932a, 1932b.
Chu, 1931.

Clemens and Wilby, 1946.
Cooper, 1803.
Cowan, 1938.

Cuvier and Valenciennes, 1831.
Delsman and Hardenburg, 1934
Doniantay, 1940.
Eckles, 1949a, 1949b.
Eigenmann, 1892.

Eigenmann and Eigenmann, 1890, 1891.
Evermann and Seale, 1907.
FAO, 1949.
Fish, 1948.
Fowler, 1904a, 1923a, 1923b, 1927, 1928, 1929, 1931, 1934,

1938, 1944, 1949.
Fowler and Ball, 1925.
Praser-Brunner, 1949, 19.50
Fujita and Wakiya, 1915.
Gilbert and Starks, 1904.
Godsil and Greenhood, 1948.
Graham, 1938.
Griffin, 1927.
Giinther, 1860, 1876.
Hasegawa, 1937.

Herre, 1932, 1933, 1935, 1936, 1940.
Hildebrand, 1946.
Hiratsuka and Imaiziimi, 1934.
Hiratsuka and Ito, 1934.
Holder, 1912.
Hubbs, 1916, 1928
Imaizumi, 1937.
Imamura, 1949.

Japanese Bur. Fish., 1934, 1939, 1940.
Jenkins, 1903.
Jordan, 1885.

Jordan and Evermann, 1896, 1905, 1926a, 1926b.
Jordan and Gilbert, 1881a, 1882.
Jordan and Hubbs, 1925.
Jordan and Jordan, 1922.

Distribution — Continued
Jordan and Metz, 1913.
Jordan and Seale, 1906.
Jordan and Snyder, 1900, 1901.
Jordan and Starks, 1907.
Jordan, Tanaka, and Snyder, 1913.
Kanamura and Imaizumi, 1935.
Kanamura and Yazaki, 1940a, 1940b.
Kimura, 1941, 1942b.
Kishinouye, 1915a, 1919c, 1922c, 1923.
Kochi Pref. Fish. Expt. Sea., 1923b, 1924.
Kumata et al., 1941.
lesson, 1830.
Lord, 1927.
Macleay, 1881.
Martin, 1938.
Matsubara, 1943.
McCulloch, 1922.
Meek and Hildebrand, 1923.
Metz, 1912.
Mori, 1928.

Nakamura, 1938, 1939b, 1943. 1949.
Nichols and Murphy, 1922, 1944.
Okada and Matsubara, 1938.
Okinawa Pref. Fish. Expt. Sta., 1943.
Okuma, Imaizumi, and Maki, 19.35.
Phillipps, 1927a, 1927b.
Phillipps and Hodgkinson, 1922.
Powell, 1937.
Reeves, 1928.
Richardson, 1846.
Roedel, 194Sa, 1948b.
Roughly, 1916.
Samson, 1940.
Schaefer, 1948c.
Schmidt, 19.30.
Schmitt and Schultz, 1940.
Schultz, 1949.
Schultz and DeLacy, 1936.
Seale, 1940.

Serventy, 1941, 1942a, 1942b, 1947, 1948.
Shapiro, 1948a, 1948b.
Smith and Schaefer, 1949.
Snyder, 1904.
Soldatov, 1929.
Soldatov and Lindberg, 1930.
South Seas Govt.-Gen. Fish. Expt. Sta., 1937a, 1937b,

1941a.
Starks, 1918.
Starks and Morris, 1907.
Stead, 1906, 1908.

Takao Prov. Fish. Expt. Sta., 1927.
Tanaka, 1912, 1931.
Taranetz, 1937.
Thomi>son and Higgins, 1919.
Tinker, 1944.
Tirant, 1929.
Tominaga, 1943.
Tubb, 1948.
Ulrey, 1929.

BIBLIOGRAPHY ON PACIFIC TUNAS

33

Distribution — Continued

Ulrey and Greeley, 1928.

Wade, 1949.

Waite, 1907, 1921, 1928.

Walford. 1931, 1937.

Weber, 1913.

Whitphead. 1929, 1931.

Whitley, 1928, 1937, 1947.
Distribution correlated with water temperature

Tal<ayama and Ando, 1934.

Takayama, Ideda, and Ando, 1934.

Uda, 19,H5a, 1935b, 193G, 1940b.

EfXKS

De.Jong, 1940.

Delsnian, 19,31.

Del.sman and Hardenburg, 1934.

Hatai et al., 1941.

Marr, 1948.

Nakannira, 1938, 1949.

Nakamura Res. Staff, 1949.

Watanabe, H., 19.39.

Yabe and Mori, 1948.
Enemies

Bennett, 1840.

Iiuaniura, 1949.

Ki.shinouye, 1923.

Tinker, 1944.

Walford, 1937.

Eiithynnus

Common names

Fisli, 1948.
Distribution
Fish, 1948.

Euthimnus alleterata. See Eutlnjnnus nlletfrratiis.

Euthynnus alleteratiis. See Euthynniis aUctteratus.

Euthjiiintis aUctteratus
Classification

Hildebrand, 1946.

Okadn and Matsubara, 1938.
Common names

Del.sman and Hardenburg, 1934.

FAO, 1949.

Jordan and Evermann, 1905.

Jordan and Jordan, 1922.

Jordan and Snyder, 1901.

Jordan. Tanaka, and Snyder, 1913.

Okada and Matsubara, 1938.

Serventy, 1941.

Tinker, 1944.

Whitley, 1947.
Compared with Euthynnus lineatu-s

Sclimitt and Sehultz, 1940.
Compared with Xlediterraneaii Thynmis thunnina

Teniminck and Schlegel. Is.'iO.
Compared with Thynnus petamys

Cantor, 18.TO.
Compared with M'audcrer wallisi

Wliitley, 1937.

Euthynnus aUctteratus — Continued
Description

Boesemau, 1947.

Cantor, 18.50.

Delsnian and Hardenburg, 19,34.

Fowler, 1904b, 1928.

Giinther. 18G0, 1S7C.

Hildebrand, 194G.

Jordan and Evermann, 1905.

Macleay, 1881.

Meek and Hildebrand, 1923.

Okada and Matsuliara, 1938.

Sen-enty, 1941.

Tinker, 1944.
Distriliution

Bleeker, 1852, 1860a, 1860b, 1861a, lS61b, 1862, 1865a,
lS65b.

Cantor, 1S50.

Chabanaud, 1926.

Chapman, 1946.

Delsman and Hardenburg, 1934.

FAO, 1949.

Fowler, 1928, 1931, 19.38. 1944.

Fowler and Ball, 1925.

Giinther, 1860, 1876.

Herre, 19.32, 1940.

Hildebrand, 1946.

Jenkins, 1903.

Jordan and Evermann, 1905.

Jordan and .Tordan. 1922.

Jordan and Seale, 1906.

Jordan and Snyder, 1901.

Jordan, Tanaka, and Snyder, 1913.

Macleay, 1881.

McCulloch, 1922.

Meek and Hildebrand, 1923.

Okada and Matsubara, 1938.

Riehardson, 1S40.

Schmidt, 19.30.

Schmitt and Schultz, 1940.

Serventy. 1941.

Stead. 1908.

Tanaka, 1931.

Tinker, 1944.

Tirant, 1929.

Weber. 1913.

Whitley, 1947.
Eggs

DeJong, 1940.

Delsman, 1931.

Delsman and Hardenburg, 1934.
Figured

Delsman and Hardenburg, 1934.

Fowler, 1928.

Giinther, 1876.

Jordan and Evermann. 190.">.

Jordan, Tanaka. ,uid Siiyiler. 1913.

Kitahara, 1897.

Serventy, 1941.

Temminck and Schlegel. ISiiO.

Tinker, 1944.

34

FISHERY BULLETIN OF THE FISH AKD WILDLIFE SERVICE

Eiithynnus aJlcttrrntiis — Continued
Food

Hildebrand, 1!>46.
Keys

Delsman and Hardenburg, 1934.

Hildebraud, 194G.

McOulIoch, 1022.

Meek and Hildebrand, 1923.

Okada and Matsubaia, 1938.

Serventy, 1941.
Parasites

Manter, 1940.

Van Cleave, 1940.
Reproduction

Delsman and Hardenburg, 1934.
Synonymy

Boeseman, 1947.

Cbevey, 1934.

FAO, 1949.

Fowler, 1904b, 1928.

Giinther, 1860. 1876.

Hildebrand, 1946.

Jenkins, 1903.

Jordan and Evermann, 1905.

Jordan, Tanaka, and Snyder, 1913.

McCulloch, 1922.

Meek and Hildebrand, 1923.

Richardson, 1846.

Tanaka, 1931.

Weber, 1913.
Young

Delsman, 1931.

Delsman and Hardenburg, 1934.

Giinther, 1889.
Etithi/nnus allittcratus. See Eiitlii/nniis alletteratus.
Eiiflnjtni'us Uneatus
Anatomy

Kisbinouye, 1923.

Schaefer and Marr, 1948b.
Classification

Fraser-Brunner, 1949.

Kisbinouye, 1923.
Common names

Kisbinouye, 1923.

Walford, 1937.
Compared with Eiithiinnus alletteratus

Sehmitt and Schultz, 1940.
Description

Fowler, 1938.

Kisbinouye, 1919c, 1923.

Schaefer and Marr, 1948b.

Seale, 1940.

Walford, 1937.
Distribution

Fowler, 1938, 1944.

Fra-ser-Brunner, 1949.

KLsbinouye, 1919c, 1923.

Roedel, 194.8a.

Schaefer, 1948c.

Schaefer and Marr, 1948b.

Eiitliynnus lincatus — Continued
Description — Continued

Sehmitt and Schultz, 1940.

Seale, 1940.

Walford, 1937.
Figured

Fowler, 1944.

Fraser-Brunner, 1949.

KLsbinouye, 1923.

Schaefer and Marr, 1948b.

Walford, 1937.
Pood

Kisbinouye, 1923.

Walford, 1937.
Habits

Ki.shinouye, 1923.
Keys

Fraser-Brunner, 1949.

Kisbinouye, 1923.

Walford, 1937.
MerLstic characters

Schaefer and Marr, 1948b.
Reproduction

Schaefer, 1948c.

Walford, 1937.
Synonymy

Fowler, 1938, 1944.

Fraser-Brunner, 1949.

Kisbinouye, 1923.
Young

Schaefer, 1948e.

Schaefer and Marr, 1948b.
Enthyiiniis macroptera
Distriltution

Tubb, 1948.
Euthynnus pelamis. See Kntsuwomis prlamis.
Euthynnus pelamys. See Kntsiiironus iiehnnis.
Euthynnvs vagans. See Katsuwonus pelamis.
Euthynnus wallisi
Distribution

Fowler, 1949.
Synonymy

Fowler, 1949.
Euthynnus yaito
Anatomy

Kisbinouye, 191.5a, 191.5b, 1919a, 1923.
Chemical analysis

Miyauchi, 1915.
Classification

Fraser-Brunner, 1949.

Kisbinouye, 1915a, 1923.

Nakamura, 1939b.

Okada and Matsubara, 1938.
Common names

Cbevey, 1932a.

Fujita and Wakiya, 1915.

Herre and Uniali, 1948.

Kisbinouye, 1915a, 1923.

Nakamura. 1939b.

Okada and Matsubara, 1938.

BIBLIOGRAPHY ON PACIFIC TUNAS

35

EiitJniinuis i/aito — Continued
Couimon names — Continued

Shapiro, 19-J8b.

Toniinaga, 1943.
Compared with Wanderer icallisi

Whitley, 1937.
De.scription

Clievey, ]!»32a.

Kishinouye, 1915a, 1923.

Oliada and Matsubara, 1938.

Tominaga, 1943.
Di.stributlon

Chevey, 1932a, 1932b.

Domantay, 1940.

Eckles, 1949a.

Fraser-Brnnner, 1949.

Fnjita and Wakiya, 1915.

Godsil and Greenhood, 1948.

Herre, 1933, 1940.

Jordan and Everniann, 1926a.

Jordan and Hubbs, 1925.

Kishinou.ve, 1915a, 1922c, 1923.

Okada and Matsubara, 1938.

Sphaefer, 194Sc.

Shapiro, 194Sb.

Smith and Schaefer, 1949.

Tominaga, 1943.
Figured

Chevey, 1932a.

Domantay, 1940.

Fraser-Brunner, 19^9.

Kishinouye, 1915a, 1923.

Smith and Schaefer, 1949.
Food

Herald, 1949.

Kishinouye, 1923.

Tominaga, 1943.

Welsh, 1949.
Habits

Kishinouye, 1923.

Tominaga, 1943.
Keys

Brock, 1949.

Fraser-Brunner, 1949.

Kishinouye, 1915a, 1923.

Okada and Matsubara, 1938.
Measurement data

Bonham, 1946.
Parasites

Kishinouye, 1923.
Reproduction

Kishinouye, 1923.

Schaefer, 1948c.
Synonymy

Chevey, 1932a, 19.34.

Fraser-Brunner, 1949.

Jordan and Hubbs, 1925.

Kishinouye, 1923.

Nakamura, 1939b.

EiitliiDDiiix i/ailo — Continued
Young
Kishinouye, 1919b, 1923, 1924.
Schaefer, 1948c.
Euthynux alletteratus. Set- Euthynnus allettcratus.
Evolution
Based on internal anatomy
Kishinouye, 1919a.
Exploitation rates

Tauchl. 1940a, 1940b, 1940c.

Fishing conditions

Correlated with area

Hart and Hollister, 1947.
Hart et al., 1948.

Correlated with astronomical phenomena. See Astro-
nomical phenomena.

Correlated with oceanography. See Oceanographic
conditions.

Correlated with .season
Hart et al., 1948.
Inanami, 1942b.
Whitehead, 1929.
Fishing grounds

Location correlated with oceanography. See Oceano-
graphic conditions.
Food

Anonymous, 1938.

Asano, 1939.

Ban, 1941.

Bennett, 1840.

Chapman, 1946.

Clemens and Wilby, 1946.

Delsman and Hardenburg, 1934.

Eckles, 1949b.

Fitch, 19.50.

Formosa Govt.-Gen. Fish. Expt. Sta., 1933a.

Hart and Hollister, 1947.

Hart et al., 1948.

Hatai et al., 1941.

Herald, 1949.

Hildebrand, 1946.

Imamura, 1949.

Japanese Bur. Fish., 1934, 1939, 1940.

Jordan and (3illiert, ISSlb, 18S2.

Kanamura and Yazaki, 1940a, 1940b.

Kishinouye, 1895, 1915a, 1917b, 192:j.

Kuronuma, 1940.

Marukawa, 19.39.

Miyama, Sartiya, and Hasegawa, 1939.

Nakamura, 1936, 1943. 1949.

Nakamura Res. Staff, 1949.

Okuma, Imaizuml, and Maki, 1935.

Scagel. 1949.

Serventy. 1942a.

Shapiro, 1948a.

Starks, 1918.

Starks and Morris, 1907.

Su.veliiro. 1936, 19.38. 1942.

Taihoku I'rov. Fish. Expt. Sta., 1928, 1929.

36

FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE

Food — Continued
Tinker. 1044.
Tominasa, 1043.
Walford, 1037.
Watanabe, H., 1939.
Welsh, 1949.
Whitley, 1937.
Tabe and Mori, 1948.

Oermo alalunga. See Thuniuis germo.

Germo alntniign. See Thunnus gcrnio.

Germo albacores. See Neotlmnnus itosiU.

Germo argentiviftafus. See Neothioinus argentivittaUis.

Germo germo. See Thnnntis germo.

Germo germon. See Thunnus germo.

Germo macroptenis. See Neothvv»us macroiiterus.

Germo sibi. See Parathtinniis sibi.

Gravity, specific. See Specific gravity, also Oceanographic

conditions.
Growth

Aikawa and Kato, 1938.

Brock, 1943.

Kimura, 1932, 1935.

Kishiuouye, 1923.

Schaefer, 194Sa, in4Sb.
GymnosarcLa afflnis. See Kafsuironns pelamis.
Giimnosarda alletterata. See Euthynnns allettcratus.
Gymnosarda pelamis. See Kcitsuwonus pelamis.

Habits

Brock, 1949.

Iniamnra, 1949.

Jordan and Gilbert, 1882.

Kida, 1936.

Kishinouye, 191.5a, 1923.

jS'akannira, 1049.

Roughly, 1016.

Schaefer, 1048b.

Sei-venty, 1042a.

Shapiro, 1948a.

Tinker. 1944.

Tominasa, 1943.

Ucbida, 1923.

Uda, in.3.5h. 1040a.

Uda and Tsukushi, 1934.
Hermaphroditism

Nakamura, 1935.
Hormones

Jligita and Arakawa, 1948.

Oya and Takahn.shi. 1936.

Toyama et al., 1041.

Juveniles. See Young.

Katsuwonidae
Anatomy

Kishinouye, 1017a, 1919a
Classification

Kishinouye, 1017a.
Compared with AHothunnns fallal

Serventy, 1948.

Katsuwonidae — Continued
Keys

Jordan and Hubbs, 1925.
Katsuiconus pelamis
Age

Aikawa, 1937.
Aikawa and Kato, 1938.
Higashi, 1941b.
Kimura, 1941.
Okamoto, 1940.
Yabe and Mori, 1948.
Anatomy

Eckles, 1949b.
Godsil and Byers, 1944.
Higashi, 1041a.
Imamura, 1049.

Kishinouye, 1015a, 1015b, 1918, 1919a, 1923.
Matsui, 1942a. 1942b.
Suyehiro, 1936, 1038, 1941, 1942.
Body condition
Aikawa, 19.37.
Aikawa and Kato. 1038.
Ikebe and Jlatsumoto, 1037.
Onodera, 1041.

South Seas Govt.-Gen. Fish. Expt. Sta., 1941d.
Suyehiro, 1036, 1038.
Body temperature
Uda, 1041.
Watanabe, N., 1941.
Catch per unit of effort

Kanamura and Yazaki. 1940a, 1940b.
Chemical analysis
Hijrashi and Hirai, 1948.

Kodama, liziika, and Harada, 1934.

Miyania and Osakabe, 1938, 1940.

Miyauchi, 1015.

Okuda, 1918.
Classification

Fraser-Brunner, 19.30.

Godsil and Byers. 1944.

Hildebrand, 1946.

Kishinouye, 101.5a, 1023.

Nakamura, 1939b.

Okada and Matsubara, 1038.

Phillipps, 1027b.

Eoedel, 1948b.

Shapiro, 104Sa.

Soldatov and Llndberg, 1030.

Taranetz, 1037.

Walford, 1031.
Common names

Barnhart, 1036.

Craig, 1929.

Delsman and Hardenburg, 1934.

FAO, 1940.

Fish, 1948.

Fujita and Wakiya, 1915.

Herre and Umali, 1048.

Jordan and Everniann, 1806, 1005.

Jordan and Hubbs, 1925.

BIBLIOGRAPHY ON PACIFIC TUNAS

37

Katsuwonus pelamis — Continued
Common names — Continued

Jordan and Jordan, 1022.

Jordan and Snyder, liiOl.

Jordan, Tanalia, and Snyder, 1913.

Kisliinouye, 191oa, 1923.

Kiunata et al., 1941.

Naknmura, 1939b.

Okada and Matsuhara, 1938.

Phillipps, 1927b.

Roeilel, 194Sb.

Serventy, 1941.

Sliapiro, 1948a, 1948b.

Smith, 1947.

Starks and Morris, 1907.

Taiiaka, 1912.

Tinker, 1944.

Toniinaga, 1943.

Ulrey and Greeley, 1928.

Walford, 1931. 1937.

Whitley, 1947.
Compared with Thynnus afflnis

Cantor, ISoO.
Description

Barnhart, 1936.

Bennett, 1840.

Bleeker, 1856.

Boeseman, 1947.

Clemens and Wilby, 1946.

( 'uvier and Valenciennes, 1934.

Di'lsuian and Hardenburg, 1934.

Eigeumann and Eigenmann, 1890.

Fouler, 1028, 1938.

Fraser-Brunuer, 1050.

Godsil and Byers, 1944.

Giinther, 1860, 1876.

Hildebrand, 1046.

Inianiura, 1940.

Jordan and Evermann, 1905.

Kishinouye, 1915a, 1922b, 1923.

Le.sson, 1830.

Macleay, 1881.

Meek and Hildebrand, 1023.

Nakamura, 1930b.

Okada and Matsubara, 1938.

Roedel, 194Sb.

Seale, 1940.

Serventy, 1041.

Shapiro, 1948a.

Soldatov and Lindberg, 1930.

Stead, 190(!.

Tanaka, 1012.

Temminck and Schlegel, 1&50.

Tinker, 1044.

Toiniiiaga, 1043.

Walford, 1931, 1937.
Distribution

Abe, 1939.

Anonymous, 1941.

Barnhart, 1936.

Katsuwonus pelamis — Continued
Distribution — Continued

Bleeker, 1856, 1860a, 1862, 1865a.

Chapman, 1046.

Clemens and Wilby, 1046.

Cuvier and Valenciennes, 1831.

Del.snian and Hardenburg, 1934.

Doniantay, 1040.

Eekles, 1940a.

Eigenmann, 1892.

Eigenmann and Eigenmann, 1890, 1891.

Evermann and Seale, 1907.

FAO, 1949.

Fi.sh, 1948.

Fowler, 1928, 1931, 1934, 1938, 1944, 1949.

Fraser-Brunner, 19.50.

Fujita and Wakiya, 1915.

Godsil and Greenhood, 1948.

Gunther, 1860, 1876.

Herre, 1932, 1033, 1935, 1936, 1940.

Hildebrand, 1946.

Imamura, 1949.

Jenkins, 1903.

Jordan and Evermann, 1896, 1905.

Jordan and Hubbs. 1025.

Jordan and Jordan, 1922.

Jordan and Seale, 1006.

Jordan and Snyder, 1001.

Jordan and Starks, 1907.

Jordan, Tanaka, and Snyder, 1913.

Kanamura and Yazaki, 1040a, 1040b.

Kimura, 1041, 1942b.

Kishinouye, 1015a, 1023.

Kumata et al., 1041.

Lesson, 1830.

Macleay, 1881.

Martin, 1038.

Matsubara, 1943.

McCulloch, 1022.

Meek and Hildebrand, 1923.

Nakamura, 1939b.

Nichols and Murphy, 1944.

Okada and Matsubara, 1938.

Okinawa Pref. Fish. Expt. Sta., 1943.

Phillipps, 1027a, 1927b.

Phillipi)s and Hodgkinson, 1022.

Reeves, 1928.

Richardson, 1846.

Roedel, 1948b.

Roughly, 1916.

Schaefer, 1948c.

Seale, 1940.

Serventy, 1041, 1947.

Shapiro, 194Sa, 1948b.

Smith and Schaefer. 1940.

Soldatov and Lindberg, 1930.

South Seas Govt.-Gen. Fish. Expt. Sta., 1937a.

Starks and Morris, 1907.

Stead, 1906, 1908.

Tanaka, 1912, 1931.

38

FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE

Katsuivonus pelamis — Continued
Distribution — Continued

Taranetz, 1937.

Tinker, 1944.

Tominaga, 1943.

Ulrey, 1929.

Ulrey and Greeley, 1928.

Waite, 1907.

Walford, 1931, 1937.

Whitehead, 1929.

Whitley, 1947.
Distribution correlated with water temperature

Takayama, Ikeda, and Ando, 1934.

Uda, 1935b, 1936, 1940b.
Egss

Hatai et al., 1941.

Marr, 1948.

Nakanmra Re.s. Staff, 1949.

Yabe and Mori, 1948.
Enemies

Imaraura, 1949.

Tinker, 1944.
Figured

Barnhart, 1936.

Clemens and Wilby, 1946.

Cuvier and Valenciennes, 1831.

Domantay, 1940.

Eckles, 1949a.

Fraser-Brunner, 1950.

Godsil and Byers, 1944.

Jordan and Evermann, 1905.

Kishinouye, 1915a, 1923.

Kitahara, 1897.

Kumata et al., 1941.

Lesson, 1830.

McCulloch, 1922.

Nakamura, 19.39b.

Roedel, 1948b.

Serventy, 1941.

Shapiro, 1948a.

Smith and Schaefer, 1949.

Tanaka, 1912.

Temminck and Schlegel, 1850.

Tinker, 1944.

Walford, 1931, 1937.
Fishing conditions correlated with oceanography

Aikawa, 19.33.

Chiba Pref. Fish. Expt. Stn., Katsuura Br., 1936, 1937,
1938, 1941.

Formosa Govt.-Gen. Fish. Expt. Sta., 1930, 1931, 1932,
1933b, 1934.

Imamura, 1949.

Inanami, 1941, 1942d.

Kagoshima Pref. Fish. Expt. Sta.. 1025, 1926a, 1926b,
1927b, 1928a, 1929a. 1930ii, 1931a, 1932a, 1933a, 1935,
1936a, 1937.

Kanamura and Yazaki, 1940b.

Kawamura, 1939.

Kimura, 1941, 1949.

Kochi Pref. Fish. Expt. Sta., 1923a.

Katsiiironus pcUimis — Continued

Fishing conditions correlated with oceanography — Con.

Kumamoto Pref. Fish. Expt. Sta., 1946.

Mie Pref. Fish. Expt. Sta., 1930a, 1930b, 1930d.

Okinawa Pref. Fish. Expt. Sta., 1940a, 1943.

Sasaki, 1939a.

Shapiro, 1948a.

Shimamura, 1927.

Shizuoka Pref. Fish. Expt. Sta., 1936, 1937.

South Seas Govt.-Gen. Fish. Expt. Sta., Iii37c, 1938.
1942, 1943b.

Taihoku Prov. Fish. Expt. Sta., 1927a, 1927b, 1929,
1932.

Takayama, Ikeda, and Ando, 1934.

Uda, 1935b, 1938, 1939, 1940c.

Uehara, 1941.

Yabe and Mori, 1948.
Fishing conditions correlated with weather

Kanamura and Yazaki, 1940b.

Okinawa Pref. Fish. Expt. Sta., 1940a, 1943.

Taihoku Prov. Fish. Expt. Sta., 1927a, 1927b.

Uda and Watanabe, 1938.
Food

Clemens and Wilby, 1946.

Delsman and Hardenburg, 1934.

Eckles, 1949b.

Hatai et al., 1941.

Hildcbrand, 1946.

Imamura, 1949.

Kishinouye, 1917b, 192.3.

Nakamura Res. Staff, 1949.

Shapiro, 1948a.

Suyehiro, 1936, 1938, 1942.

Taihoku Prov. Fish. Expt. Sta., 1928, 1929.

Tinker, 1944.

Tominaga, 1943.

Walford, 1937.

Yabe and Mori, 1948.
Growth

Aikawa and Kato, 1938.
Habits

Imamura, 1949.

Kishinouye, 1923.

Shapiro, 1948a.

Tinker, 1944.

Tominaga, 1943.

Uchida, 1923.

Uda, 1935b, 1940a.

Uda and Tsukushi, 19.34.
Hermaphroditism

Nakamura, 1935.
Hormones

Miglta and Arakawa, 1948.

Oya and Takahashi, 1936.

Toyama et al., 1941.
Keys

Brock, 1949.

Delsman and Hardenburg, 1934.

Fraser-Brunner, 1950.

Godsil and Byers, 1944.

BIBLIOGRAPHY OX PACIFIC TUNAS

39

Katsuwonus pelamis — Continued
Keys — Cimtin\UMl

HiMebratKl. 104f).

Kishinoiiye. lOlya, 1923.

MtCull(Hh, lft22.

Meek and Hildebraiul. 1923.

Okaila an.-i Mat.subara, 1938,

Roedel, 1948b.

Serventy, 1941.

Soldatov and Lindber^', 1930.

Tai-iUietz, 1937.

Walford, 1931, 1937.
Length-weiglit relation

Bonham, 1946.
Measurement data

Aikawa and Kato, 1938.

Bonham, 1946.

Godsil and Byers. 1944.

Higashi, 1940a, 1040b, 1941a, 1941b, 1942.

Ikebe and Matsumoto. 1937.

Kagoshima Pref. Fish. Expt. Sta., 192.">, 1926a, 192Tb,
192Sa, 1929a, 1936a, 1937, 1938a, 1939a, 1940a, 1941.

Kodama, liziika, and Harada, 1934.

Marr, 1948.

Nakamura Res. Staff, 1949.

Oita Pref. Fish. E.xpt. Sta., 1925.

Okianwa Pref. Fish. Expt. Sta., 1931.

Onod'ra, 1941.

Schaefer, 1948b.

South Seas Govt.-Gen. Fish. Expt. Sta., 1941d.

Suyehiro, 1936, 193S.

Expt. Sta., 1928, 1929.

Fish.

Taihnku Prov.

Uda, 1941.

Watanabe. N., 1941.

Yabe and Mori, 1948.

Yamamoto, 1940.
Meristic characters

Codsil and Byers, 1944.

Nakamura Res. Staff, 1949.
Migration

Hatai et al., 1941.

Imamura, 1949.

Kiniura, 1941, 1942b.

Kishinouye, 1923.

Mats\ibara, 1943.

Matsumoto, 1937.

Sasaki, 19.39a.

Shapiro. 194Sa, 1948b.

Tominaga, 1943.

Uda, 1936.

Walford, 1937.
Parasites

Bennett, 1840.

Haraila, 1928.

Kishinouye, 1923.

Manter, 1940.

Van Cleave, 1940.
Populations
Aikawa, 1937.
Godsil and Byers, 1944.

Katsuiconus pelamis — Continued
Populations — Continued
Imamura, 1949.
Tauchi, 1941.
Tominaga, 1943.

Uda and Tsukuslii, 1934.
Reproduction

Eckles, 1949b.

Hatai et al., 1941.

Imamura, 1949.

Kishinouye, 1923.

Marr, 1948.

Schaefer, 1948c.

Schaefer and Marr, 1948a.

Shapiro, 194Sb.

Walford, 1937.

Yabe and Mori, 1948.
Sex ratio

Ikebe and Matsumoto. 1937.

Marr, 1948.

Nakamura Res. Staff, 1949.
Sexual dimorphi.sm

Hatai et al., 1941.
Sexual maturity

Hatai et al., 1941.

Marr, 194S.

Matsuliara. 1943.

Matsui, 1942b.

Nakamura Res. Staff, 1949.

Okinawa Pref. Fish. Expt. Sta., 1931.

Schaefer and Marr, 1948a.

Yabe and Mori, 1948.
Size composition

Aikawa, 1937.

Aikawa and Kato, 1938.

Inanami, 1942b.

Kagoshima Pref. Fish. Expt. Sta., 1937.

Kimura, 1941.

Nakamura Res. Staff, 1949.

Okamoto, 1940.

Sasaki, 1939a.

Uda, 193.5b.

Uda and Tsukushi, 1934.

Yabe and Mori, 1948.
Swinuuing velocity

Watanabe, N., 1941.
Synonymy

Bleeker, 1856.

Boeseman, 1947.

Everniann and Seale, 1907.

F.VO, 1949.

Fish. 1948.

Fowler, 1928, 1934, 1944, 1949.

Fraser-Brunner, 19.50.

Giinther, 1S60, 1876.

Herre, 1936.

Hildelirand, 1946.

Jenkins, 1903.

Jordan and Evermann. 1896, 1905.

Jordan, Tanaka, and Snyder. 1913.

40

FISHERY BULLErriN OF THE FISH AND WILDLIFE SERVICE

Katsuwonus pelamis — Continued
Synonymy — Continued

Kishinouye, 1023.

MeCulloch, 1922.

Meek and Hildebrand, 1923.

Nakamura, 1939b.

Philllpps, 1927b.

Richardson, 1846.

Soldatov and Lindberg, 1930.

Tanaka, 1912, 1931.

Ulrey and Greeley, 1928.

Waite, 1907.
Tagging

Anonymous, 1939.

Fukuda and lizuka, 1940b.

Godsil, 1938.

Kagoshima Pref. Fi.sh. Espt. Sta., 1928a, 1936b, 1938b,
1939b, 19401).

Matsumoto, 1937.

South Seas Govt.-Gen. Fish. Expt. Sta., 1941c.

Uda, 1936.
Toung

Eckles, 1949b.

Hatai et al., 1941.

Inanami, 1942o.

Kishinouye, 1019b, 1923, 1924, 1926.

Marr, 1948.

Sehaefer, 1948c.

Schaefer and Marr, 1948a.

Yabe and Mori, 1948.
Toung as food of tuna

Kishinouye, 1917b.

Marukawa, 1939.
Katsuifonus pelamys. See Kntsuicovtis pelamis.
Katmiwomis tJagans. See Kat.s-uironiis pelamis.
Kaiicomis vayans. See Katsuwonus pelamis.
Key.*!

Brock, 1949.

Delsman and Hardenburg, 1934.
Fraser-Brunner, 1040, 1950.
Godsil and Byers, 1944.
Hildebrand, 1946.
Jordan and Evermann, 1926b.
Jordan and Hulibs, 1925.
Kishinouye, 1915a, 1923.
MeCulloch, 1922.
Meek and Hildebrand, 1023.
Nakamura, 1040.
Okada and Matsubara, 1938.
Roedel, 194Sb.
Serventy, 1941.
Soldatov and Lindberg, 1930.
Taranetz, 1937.
Wade, 1949.
Walford, 1931, 1937.
Eish inoella
Keys

Soldatov and Lindberg, 1930.

EishiiwcUa rnra
Classification

Nakamura, 1939b.

Okada and aiatsubara. 1038.
Common names

Jordan and Evennann, 1026b.

Jordan and Hubbs, 1925.

Nakamura, 1939b.

Okada and Matsubara. 1938.
Compared with Eisliiiioclhi zacalles

Nakamura, 1939b.
Description

Jordan and Evermann. 1926b.

Jordan and Hubbs. 1925.

Nakamura, 1939b.

Okada and Matsubara, 1938.
Distribution

Jordan and Evermann, 1926a, 1926b.

Jordan and Hubbs, 1925.

Nakamura. lO.'iOb.

Okada and Matsubara, 1938.
Figured

Nakamura, 1939b.
Keys

Brock, 1949.

Jordan and Evermann. 1926b.

Okada and Matsubara, 1938.
Synonymy

Nakamura, 1939b.
Kish inoella tont/r/ol
Anatom.y

Serventy, 1942b.
Common names

Serventy, 1941.

Whitley, 1947.
Compared with Kishinorlla zacalles

Serventy, 1942b.
Compared with Ncoihunnus varus

Serventy, 1942b.
Compared with Thunnux niaeeoyi

Sei-venty, 1041.
Compared with Thunnus nicolsoni

Serventy, 1942b.
Compared with Thunnus tonggol

Serventy, 1942b.
Description

Serventy, 1941, 1942b.
Distiibution

Serventy, 1941, 1942a, 1942b.

Whitley, 1947.
Figured

Serventy, 1941, 1942b.
Food

Serventy, 1942a.
Habits

Serventy, 1942a.
Keys

Serventy, 1941.
Length-weight relation

Serventy, 1941.

BIBLIOGRAPHY ON PACIFIC TUNAS

41

Kishinoelln tonijijol — Continued
Measurement data

Serventy, 1942b.
Reproduction

Serventy, 1042a.
Synonymy

Serventy, 1942b.
KUhinoclla zacalles
Classification

Fraser-Brunner, 1950.

Nicliols and LuMonle, 1941.
Compared witli Kinliiiwclla rara

Nakamura. 19:!9b.
Compared with KiHhinoella tonggol

Serventy, 1942b.
Description

Fraser-Brunner, 19.50.

Jordan and Everniann. 1926b.
Distribution

Fraser-Brunner, 10.10.

.Jordan and Bvermann, 1926b.
Figured

Fraser-Brunner, 19,")0.

Jordan and Everniann, 1926b.
Keys

Fra.?er-Brunner, 19.50.

Jordan and Everniann. 1926b.
Synonymy

FVaser-Brunner, 1950.

Length-weight data. See Morphometries.

Maclierel, frigate. See Auxis spp.
Management

Scbaefer, 194Sc.
Maturity

Anonymous, 1938.

Ban, 1941.

Clark, 1929.

Hatai et al., 1941.

Ikebe, 1939.

Imaizumi, 1937.

Kanamura and Imaizumi, 1935.

Kanamura and Yazaki, 1940a, 1940b.

Kato, 1940.

Marr, 1948.

Matsubara, 1943.

Matsui, 1042b.

Nakamura, 1938.

Nakamiira Res. Staff, 1949.

Okinawa Pref. Fish. Expt. Sta.. 1931.

Okuma, Imaizumi, and Maki, 1935.

Schaefer, 1948b.

Scbaefer and Marr, 1948a.

Soc. Prom. Ocean. Fish., 19.36.

Watanabe, H., 1930.
Measurement data. See Morphometries.
Migration.

Cobb, 1919.

Hatai et al., 1941.

Migration — Continued
Imamura, 1949.
Kimura, 1941, 1942b.
Kishinouye, 1923.

Koehi Pref. Fisli. Expt. Sta., 1923b, 1924.
Matsubara, 1943.
Matsiimoto, 1937.
Nakamura, 1943, 1949.
Sasaki, 1939a, 1939b.
Serventy, 1941.
Shapiro, 104Sa, 104Sb.
Soc. Prom. Ocean. Fish., 1936.
Tauclii, 194()b.
Tominaga, 1943.
Uda, 1936.
Walford, 1937.
Whitehead, 1931.
Morphometries

Length-weight relation

Bonhani, 1946.

Hiratsuka and Morlta, 1935.

Schaefer, 1948a.

Serventy, 1941.
Measurement data

Aikawa and Kato, 1938.

Anonymous, 1938.

Bonham, 1946.

Brock, 1043, 1940.

Formosa Govt.-Gen. Fish. Expt. Sta., 1933a.

Godsil, 1948.

Godsil and Byers, 1944.

Higashi, 1940a, 1940b, 1911a, 1941c, 1942.

Hiratsuka and Imaizumi, 1934.

Hiratsuka and Ito, 1934.

Ikebe, 1939, 1040a, 19401), 1040c, 1041a, 1941b.

Ikebe and Matsumoto, 1037.

Inanami, 1940a.

Japanese Bur. Fish., 1930, 1940.

Kagoshima Pref. Fish. Expt. Sta., 1925, 1926a. 1027b,
1928a, 1929a, 1036a, 1937, 1938a, 193!)a, 1940a, 1941.

Kanamura and Imaizumi, 1935.

Kanamura and Tazaki, 1940a, 1940b.

Kdihinia, lizuka, and Harada, 1934.

Marr, 1948.

Miyama, Saruya, and Hasegawa, 1939.

Nakamura, 1036, 1930a, 1930b.

Nakamura Res. Staff, 1949.

Oita Pref. Fish. Expt. Sta., 1925, 1927a. 1027b, 1930.

Okinawa Pref. Fisli. Expt. Sta.. 1931.

Okuma, Imaizumi, and Maki. 1935.

Onodera, 1941.

Schaefer, 1948a, 194Sb.

Serventy, 1942b, 1948.

South Seas Govt.-Gen. Fish. Expt. Sta., 1941d, 1943a.

Suyehiro, 1036, 1938.

Tailioku Pi-ov. Fish. Expt. Sta., 1028, 1029.

Uda, 1932, 1941.

Uno, 1036b.

Wade, 1949.

Watanalie, Ilajinie, 1939.

42

FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE

M(iri)hometrics — Continued
Measurement data — Continued

Watanabe, Haruo, 1940.

Watanabe, N., 1941.

Tabe and Mori, 1948.

Yaiuamoto, 1940.
Meristic characters

Clark, 1929.

Godsil and Byers, 1944.

Nakamura Re.s. Staff, 1949.

Schaefer and Marr, 1948b.

Wade, 1949.
Methods of measurement

Godsil, 1948.

Godsil and Byers, 1944.

Marr and Schaefer, 1949.
Sex ratio

Brock, 1943.

Ikebe and Matsumoto, 19.37.

Marr, 194S.

Miyama, Saruya, and Hasegawa, 1939.

Nakamura Res. Staif, 1949.

Ncothiinnus

Compared with ScmatliK units

Fowler, 1933.

Nakamura, 1939a.
New species recorded

Jordan and Bvermann, 1926a.
Neotliunmis albacora
Classification

Nichols and LaMonte, 1941.
Common names

Nichols and LaJIonte, 1941.
Description

Nichols and LaMonte, 1941.
Keys

Nichols and LaMonte, 1941.
Synonymy

Nichols and LaMonte, 1941.
Nrothvnnus alhacora alhacoin. See Ncoihunnns anacora.
Nrothnnmis albacora macropterus. See Neotliunnus

macropterus.
NeotMmnns allisonl
Classification

Nichols and LaMonte, 1941.
Common names

Nichols and LaMonte, 1941.
Compared with Ncothuniins macropterus

Walford, 1937.
Description

Nichols and LaMonte, 1941.
Keys

Nichols and LaMonte. 1941.
Synonymy

Nichols and LaMonte, 1941.
Neotliunnus alUsoni allisoni. See Neotliunnus allisoni.
Ncothunnus allisoni itosibi. See Neotliunnus itosihi.

Neotliunnus argentivittatus
Common names

Nichols and Mui-phy, 1922.
Description

Nichols and Murphy, 1922.
Distribution

Fowler, 1944.

Jordan and Jordan, 1922.

Nichols and Murphy, 1922.
Neotliunnus catalinae
Classification

Nichols and LaMonte, 1941.
Common names

Craig, 1929.

Nichols and LaMonte, 1941.
Description

Jordan and Evermann, 1926b.

Nichols and LaMonte, 1941.
Distribution

Jordan and Evermann, 1926b.

Ulrey, 1929.
Figured

Jordan and Evermann, 1926b.
Keys

Jordan and Evermann, 1926b.

Nichols and LaMonte, 1941.
Synonymy

Nichols and LaMonte, 1941.

Neotliunnus itosibi
Classification

Nichols and LaMonte, 1941.

Okada and Matsnbara, 1938.
Common names

Jordan and Evermann, 1926b.

Okada and Matsubara, 1938.
Compared with Neotliunnus macropterus

Nakamura, 1939a, 1939b.
DescriiJtion

Fowler, 1928.

Jordan and Evermann. 1926b.

Okada and Matsubara, 1938.

Powell, 1937.
Distribution

Domantay, 1940.

Fowler, 192S.

Jordan and Evermann, 1926b.

Martin, 1938.

Okada and Matsubara, 1938.

Powell, 1937.
Figured

Domantay, 1940.

Jordan and Evermann. 1926b.

Powell, 1937.
Keys

Jordan and Evermann. I'.t26b.

Okada and Matsubara, 1938.
Synonymy

Fowler, 1928.

Powell, 1937.

BIBLIOGRAPHY ON PACIFIC TUNAS

43

Ifeothtiiniiix nuicroptrnis
Age

Aikawa iind Kato, 1938.

Ban, 1941.

Higashi, 1941b.

Ikebe, 19:!9, 194(la. 1940h, lOJOc. 1941a, 1941b.

Kanamura and Yazaki, 1940a, 1940b.

Kiiimra, 1942a.

Schaefer, 1948b.

Tauchi, 1940b.
Anatomy

Fish, 1948.

Godsil and Byers, 1944.

Higashi, 1941e.

Kishinouye, 1915a, 1915b, 1919a, 1922a, 1923.

Matsui, 1942a.

Migita and Arakawa, 1948.

Nakamura, 1949.

Suyehiro, 1941, 1942.
Body condition

Aikawa and Kato, 1938.

Ikebe, 1939.

Kanamura and Yazaki, 1940a, 1940b.
Body temperature

Anonymous, 1938.

Kanamura and Imaizuuii, 1935.

Kanamura and Yazaki, 1940a, 1940b.

Nakamura, 1941.

Oita Pref. Fish. Expt. Sta., 1927a, 1930.
Catch per unit of effort

Formosa Govt.-Gen. Fish Expt. Sta., 1933a.

Hiratsuka and Iniaizumi, 19.34.

Hiratsuka and Ito, 1934.

Imaizuuii, 1937.

Kanamura and Imaizuuii, 1935.

Kanamura and Yazaki, 1940a, 1940b.

Nakamura, 1949.

Okuma, Imaizumi, and Maki, 1935.
Chemical analysis

Dill, 1921.

Higashi and Hirai, 1948.

Miyania and Osakabe, 1940.

Miyama, Saruya, and Hasegawa, 1939.
Classification

Fra.ser-Brunner, 1950.

Godsil and Byers, 1944.

Hildebrand, 1946.

Kishinouye, 191.ja, 1923.

Nakamura, 1939a, 1939b, 1943, 1949.

Nichols and LaJIonte, 1941.

Okada and Matsubara, 1938.

Roedel, 194Sb.

Schaefer, 194Sa.

Shapiro, 194Sa.

Soldatov and Lindberg, 1930.

Taranetz. 19:'.7.

Walford. 1931.
Coiiimun names

Barnhart, 1936.

Delsman and Hardenburg, 1934.

Neothtimius macropterus — Continued

Common names — Continued

FAO, 1949.

Fi.sh, 194S.

Fujita and Wakiya, 1915.

Herre and Uniali, 1948.

Jordan and Evermann, 1926b.

Jordan and Hubbs, 1925.

Jordan and Jordan, 1922.

Jordan and Snyder, 1901.

Jordan, Tanaka, and Snyder, 1913.

Kishinouye, 1915a, 1923.

Kumata et al., 1941.

Nakamura, 1939b. 1943, 1949.

Okada and Matsubara, 1938.

Roedel, 1948b.

Serventy, 1941.

Shapiro, 1948a, 1948b.

Smith, 1947.

Starks and Morris, 1907.

Tinker, 1944.

Ulrey and Greeley, 1928.

Walford, 1931, 1937.

Whitley, 1947.
Compared with Neothiinntis allisoni

Walford, 1937.
Compared with Xeoth minus itosibi

Nakamura, 1939a, 1939b.
Compared witli Parathunnuti iiiehachi

Roedel, 1948b.
Compared with Semathuiniiis yuildi

Nakamura, 1939b.
Compared with Tluinniis tinjiniiis

Thompson and Biggins, 1919.
Description

Barnhart, 1936.

Boeseman, 1947.

Delsman and Hardenburg, 1934.

Fowler, 1928.

Fraser-Brunner, 1950.

Godsil and Byers, 1944.

Hildebrand. 1946.

Jordan and Evermann, 1926b.

Jordan and Hubbs, 1925.

Jordan and Jordan, 1922.

Jordan and Starks, 1907.

Kishinouye, 1915a, 1923.

Matsubara, 1943.

Nakamura, 19.S9b. 1949.

Okada and Matsubara, 1938.

Roedel, 194Sb.

Seale, 1940.

Serventy, 1941.

Shapiro, 1948a.

Soldatov and Lindberg. 1930.

Starks, 1918.

Teniniinck and Schle!;el. 1N">0.

Thompson and Higgins, 1919.

Tinker, 1944.

Walford, 1931, 1937.

44

FISHERY BULLEITIN OF THE FI&H AK.D WILDLIFE SERVIC7E

Neotluinmis macroptents — Continued
Distribution
Abe, 1939.
Anonymous, 1938.
Barnhart, 1936.
Bleeker, 1852, 1862, 1865a.
Chapman, 1946.
Chu, 1931.

Delsman and Hardenburg, 1934.
Domantay, 1940.
Eckles, 1949a.
FAO, 1949.
Fish, 1948.

Formosa Govt.-Gen. Fish. Expt. Sta„ 1933a.
Fowler, 1923a, 1928, 1931, 1938, 1949.
Fi'aser-Brunner, 1950.
Fujita and Wal^iya, 1915.
Godsil and Greenhood, 1948.
Herre, 1932, 1935, 1936, 1940.
Hildebrand, 1946.
Hiratsuka and Imaizumi, 1934.
Hiratsuka and Ito, 1934.
Holder, 1912.
Hubbs, 1916.
Imaizumi, 1937.
Japanese Bur. Fish., 1934.
Jordan and Evermann, 1926a, 1926b.
Jordan and Hubbs, 1925.
Jordan and Jordan, 1922.
Jordan and Seale, 1906.
Jordan and Snyder, 1901.
Jordan and Starks, 1907.
Jordan, Tanaka, and Snyder, 1913.
Kanaraura and Imaizumi, 1935,
Kanamura and Yazaki, 1940a, 1940b.
Kimura, 1942b.
Kishinouye, 1915a, 1923.
Kochi Pref. Fish. Expt. Sta., 1923b, -924.
Kumata et al., 1941.
Martin, 1938.
Matsubara, 1943.
Nakamura, 1939b, 1943. 1949.
OUada and Matsubara, 1938.
Okuma, Imaizumi, and Maki, 1935.
Reeves, 1928.
Richardson, 1846.
Roedel, 1948b.
Schaefer, 1948c.
Seale, 1940.
Serventy, 1941.
Shapiro, 1948a, 1948b.
Smith and Schaefer, 1949.
Soldatov and Lindberg, 19.30.
South Seas Govt.-Gen. Fish. Expt. Sta., 1937a.
Starks, 1918.
Starks and Morris, 1907.
Takao Prov. Fish. Expt. Sta., 1927.
Tnnaka, 19.31.
Taranetz, 1937.
Temminck and Schlegel, 1850.

Neotliimnus macroptents — Continued
Distribution — Continued
Tinker, 1944.
Ulrey, 1929.

Ulrey and Greeley, 1928.
Walford, 1931, 1937.
Whitley, 1928, 1947.
Distribution correlated with water temperature
Takayama and Ando, 1934.
Uda, 1935a.
Exploitation rates

Tauchi, 1940b.
Figured

Anonymous, 1938.
Barnhart, 1936.

Delsman and Hardenburg, 1934.
Domantay, 1940.
Eckles, 1949a.
Fraser-Brunner, 19.50.
Godsil and Byers, 1944.
Jordan and Evermann, 1926b.
Jordan and Starks, 1907.
Kishinouye, 1915a, 1923.
Kitahara, 1897.
Kumata et al., 1941.
Nakamura, 1949.
Roedel, 1948b.
Serventy, 1941.
Shapiro, 1948a.
Starks, 1918.

Temminck and Schlegel, 1850.
Tinker, 1944.
Walford, 1931, 1937.
Fishing conditions correlated with astronomical phe-
nomena
Takao Prov. Fish. Expt. Sta., 1927.
Fishins conditions correlated with oceanography
Aikawa, 1933.
Ban, 1941.

Formosa Govt.-Gen. Fish. Expt. Sta., 1933a.
Hiratsuka and Imaizumi, 1934.
Hiratsuka and Ito, 1934.
Ikebe, 1940d, 1942.
Inanami, 1940b, 1940c, 1941, 1942d.
Japanese Bur. Fish., 1934.
Kagosbima Pref. Fish. Expt. Sta., 1926b, 1927a, 1928b,

1929b, 1930b, 1930e, 1931b, 1932b. 1933b.
Kanamura and Imaizumi, 19.35.
Kanamura and Yazaki, 1940a, 1940b.
Kawamura, 1939.
Kimura, 1942a.
Kinuira and Ishii, 1933.
Mie Pref. Fish. Expt. Sta., 1930c, 1930e.
Nakamura, 1949.
Oita Pref. Fish. Expt. Sta., 1930.
Okunia, Imaizumi, and Maki, 1935.
Shapiro, 1948a.
South Seas Govt.-Gen. Fish. Expt. Sta., 1937a, 1938,

1941b, 1942, 1943b.
Takao Prov. Fish Expt. Sta., 1927.

BIBLIOGRAPHY ON PACIFIC TUNAS

45

Neothunnus macropterus — Continued

Fishing conditions correlated with oc(>anography — Con.
Takayama and Ando, 1934.
Uehara, 1041.
Fishing conditions corrchited with weather
Formosa Govt. -Gen. Fish. Expt. Sta., 1933a.
Hiratsuka and Imaizumi, 1934.
Hiratsuka and Ito. 1934.
Kanamura and Yazaki, 1940a, 1940b.
Oita Pref. Fish. Expt. Sta., 1930.
Okuma, Imaizumi, and Maki, 1935.
Food

Anonymous, 1938.
Ban, 1941.
Chapman, 1946.
Fitch, 1950.

Formosa Govt.-Gen. Fish. Expt. Sta., 1933a.
Herald, 1949.
Hildebrand, 1946.
Japanese Bur. Fish., 1934.
Kanamura and Imaizumi, 1935.
Kanamura and Yazaki, 1940a, 1940b.
Kishinouye, 191Tb, 1023.
Marukawa, 19.39.

Miyania, Saruya, and Hasegawa, 1939.
Nakaniura, 1936, 1943, 1949.
Okuma, Imaiziirai, and Maki, 1935.
Shapiro, 194Sa.
Su.vehiro, 1942.
Tinker, 1944.
Walford, 1937.
Growth
Aikawa and Kato, 1938.
Kimura, 1932, 1935.
Kishinouye, 1923.
Schaefer, 1948a, 1948b.
Habits

Kishinouye, 1923.
Nakaniura, 1949.

Schaefer, 194Sb.

Shapiro, 1948a.
Hormones

Migita and Arakawa, 1948.

Toyama et al., 1941.
Keys

Brock, 1949.

Delsman and Hardenburg, 1934.

Fraser-Brunner, lO.'O.

Godsil and Byers, 1044.

Hildebrand, 1946.

Jordan and Evermann, 1926b.

Kishinouye, 1915a, 1923.

Nakaniura, 1949.

Okada and Matsubara, 1938.

Roedel, 1948b.

Serventy, 1941.

Soldatov and Lindberg, 1930.

Taranetz, 1037.

Wallord, 1931, 1937.

Ncoth iiiinus macropterus — Continued
Length-weight relation

Hiratsuka and Morita, 1935

Schaefer, 194Sa.
Measurement data

Aikawa and Kato, 1938.

Anonymous, 19.38.

Bonham, 1046.

Formosa Govt.-Gen. Fisli. Expt. Sta., 1933a.

Godsil, 1948.

Godsil and Byers, 1944.

Higa.shi, 1940a, 1941b, lOllc, 1042.

Hiratsuka and Imaizumi, 1934.

Hiratsuka and Ito, 1034.

Ikebe, 1039, 1040a, 104(ib, 1040c, 1941a, 1941b.

Inanami, 1940a.

Kanamura and Imaizumi, 10.35.

Kanamura and Yazaki, 1040a, 1940b.

Marr, 1948.

Miyama, Saruya, and Hasegawa, 19.39.

Nakamura, 19.36, 1939a, 1930b.

Oita Pref. Fish. Expt. Sta., lOL'.". 1027a, 1027b, 1930.

Okuma, Imaizumi, and Maki, 1935.

Schaefer, 1948a, 194Sb.

South Seas Govt.-Gen. Fish. Expt. Sta., 1943a.

Watanabe, H., 1940.
Meristic characters

Godsil and Byers, 1044.
Migration

Kochi Pref. Fish. Expt. Sta., 1923b, 1924.

Nakamura, 1943.

Shapiro, 1948a.

Tauchi, 1940b.

Walford, 1937.
Parasites

Kishinouye, 1923.
Populations

Godsil, 1948, 1049.

Godsil and Byers, 1944.

Tauchi, 1040b.
Reproduction

Hatai et al., 1041.

Ikebe, 1041b.

Kishinouye, 1923.

Marr, 1948.

Nakaniura, 103!)b, 1943, 1949.

Schaefer, 194Se.

Schaefer and Marr, 1948a.

Tinker, 1944.

Walford, 1937.
Sex ratio

Marr, 1948.

Miyama, Saruya, and Hasegawa, 1939.
Sexual maturity

Anonymous, 1938.

Ban, 1941.

Hatai et al., 1941.

Ikebe, 1039.

Imaizumi, 1037.

Kanamura and Imaizumi, 1935.

46

FISHERY BULLErriN OF THE FISH AA'D WTLDLIFE SERVICE

Neothunnus macroptervs — Continued
Sexual maturity — Continued

Kanamura and Yazaki, 1940a, 1940b.

Kato, 1940.

Marr, 1948.

Okuma, Imaizumi, and Maki, 1935.

Schaefer, 1948b.

Schaefer and Marr, 1948a.
Size composition

Aikawa and Kato, 1938.

Kiniura, 1932, 1942a.

Scliaefer, 1948b.

Schaefer and Marr, 1948a.

Tauehi, 1940b.
Survival rates

Tauehi, 1940b.
Synonymy

Boeseman, 1947.

Chu, 1931.

FAO, 1949.

Fish, 1948.

Fowler, 1928, 1931, 1949.

Fraser-P.runner, 1950.

Herre, 1936.

Hildebrand, 1946.

Jordan and Hubbs, 1925.

Jordan and Starks, 1907.

Jordan, Tanaka, and Snyder, 1913.

Kishinouye, 1923.

Nakamura, 19.39a, 19.S9b, 1949.

Richardson, 1846.

Soldatov and Lindberg. 1930.

Tanaka, 1931.

Ulrey and Greeley, 1928.
Tagging

Godsil, 1938.
Young

Kishinouye, 1924, 1926.

Schaefer, 1948c.

Schaefer and Marr. 1948a.
Neothunnus ranis
Anatomy

Kishinouje, 1915a, 1915b, 1923.

Nakamura, 1949.
Classification

Kishinouye, 191.5a, 1923.

Nakamura, 1943, 1949.

Nichols and LaMonte, 1941.
Common names

Delsman and Hardeiiburg, 1934.

Kishinouye, 1915a, 1923.

Nakamura, 1943, 1949.

Nichols and LaMonte, 1941.
Compared with Kishinoelhi loni/gol

Serventy, 1942b.
Description

Delsman and Hardenburg, 1934.

Kishinouye, 191.->a, 1923.

Nakamura, 1949.

•Nichols and LaMonte, 1941.

Neothunnus ranis — Continued
Distribution

Delsman and Hardenburg, 1934.

Herre, 1940.

Ki.shinouye, 191.5a, 1923.

Nakamura, 1943, 1949.
Eggs

Delsman and Har<lenburg, 1934.
Figured

Kishinouye, 1915a, 1923.

Nakamura, 1949.
Food

Kishinouye, 1923.

Nakamura, 1943, 1949.
Habits

Kishinouye, 1923.

Nakamura, 1949.
Keys

Delsman and Hardenburg, 1934.

Ki.shinonye, 1915a, 1923.

Nakamura, 1949.

Nichols and LaMonte. 1941.
Migration

Nakamura, 1943.
Reproduction

Delsman and Hardenburg, 1934.

Nakamura, 1943.
Synonymy

Kishinouye, 1923.

Nakamura, 1949.

Nichols and LaMonte, 1941.
Neothunnus ranis xucalles. See KishinoeUa zacalles.
Neothunnus tonf/gol
Description

Jordan and Evermann, 1926b.
Distribution

Jordan and Evermann. 1926b.
Keys

Jordan and Evermann. 1926b.
Synonymy

Jordan and Evermann, 1926b.
Neothynniin macroptcru.i. See Neothunnus macroptcrus.
Nicotinic acid

Higashi and Hirai, 194S.
Nomenclature, tuna. See Tuna, common names.

Oceanographie conditions. See also Currents ; Salinity ;
Specific gravity : Tides ; Water.
Correlated with fishing
Ban, 1941.

Formosa Govt.-Gen. Fish. Expt. Sta., 1933a.
Hiratsuka and Imaizumi, 1934.
Hiratsuka and Ito, 19.34.
Ikehe, 1942.
Imamura, 1949.

Kanamura and Imaizumi, 1935.
Kanamura and Yazaki, 1940b.
Kawamura, 1939.

Kochi Pref. Fish. Expt, Sta., 1923a.
Nakamura, 1949.

BIBLIOGRAPHY ON PACIFIC TUNAS

47

Oeeanographic conditions — Continued
Correlated with fishing — Continued

Oita Pref. Fish. Espt. Sta., 1930.

Okuma, Imaizunil, and Malii, 1935.

Scagel, 1949.

Shapiro, liMSa.

South Seas Govt.-Gen. Fish. Expt. Sta., 1937c, 1938,
ISMlb.

Taihoku Prov. Fish. Expt. Sta., 1927a, 1927b.

Uda, 1935b, 1940c.
Correlated with location of fishing grounds

Inanami, 1942a.

Soc. Prom. Ocean. Fish., 1936.
Orcynua. See Thunnidae.
Orcynus alalonffa. See Thunnus germo.
Orcynua gernw. See Thunnus germo.
Orcynus paciflcus. See Thunnus germo.

Parasites

Bennett, 1840.
Harada, 1928.
Kishinouye, 1923.
Manter, 1940.
Van Cleave, 1940.
Parathunmis
Keys

Soldatov and Lindberg, 1930.
Pnrathunnus mebachi
Anatomy

Godsil and Byers, 1944.

Higashi, 1941c.

Kishinouye, 191.5a, 1915b, 1918, 1919a, 1922a, 1923.

Nakaniura, 1949.
Body temperature

Kanamura and Imaizumi, 1935.

Oita Pref. Fish. Expt. Sta., 1927a, 1930.
Catch per unit of effort

Imaizumi, 1937.

Japanese Bur. Fish., 1939.

Kanamura and Imaizumi, 19.35.

Kanamura and Yazaki, 1940a.

Nakamura, 1949.
Chemical analysis

Miyama and Osakabe, 1940.

Miyauchi, 1915.
Classification

Godsil and Byers, 1944.

Kishinou.ve, 191.5a, 1923.

Nakamura, 1939b, 1943, 1949.
Common names

Kishinouye, 191.5a, 1923.

Kumata et al., 1941.

Nakamura, 1939b, 1943, 1949.
Compared with Neothunnus macropterm

Roedel, 194Sb.
Compared with Thunnus germo

Roedel, l948b.
Description

Godsil and Byers, 1944.

Kishinouye, 191.5a, 1923.

Nakamura, 10.'{9b, 1949.

929179'— 51 4

Parathunnus mebachi — Continued
Distribution

Fish, 1948.

Imaizumi, 1937.

Japanese Bur. Fish., 1934.

Kanamura and Imaizumi, 1935.

Kanamura and Yaziiki, 1940a.

Kimura, 1942b.

Kishinouye, 1915a, 1923.

Kochi Pref. Fish. Expt. Sta., 1923b, 1924.

Kumata et al., 1941.

Matsubara, 1943.

Nakamura, 1939b, 1943, 1949.

Takao Prov. Fish. Expt. Sta., 1927.
Distribution correlated with water temperatures

Takayama and Ando, 1934.
Figured

Godsil and Byers, 1944.

Kishinouye, 1915a, 1923.

Kumata et al., 1941.

Nakamura, 1949.
Fishing conditions correlated with astronomical phe-
nomena

Takao Prov. Fish. Expt. Sta., 1927.
Fishing conditions correlated with oceanography

Aikawa, 1933.

Fukuda and lizuka, 1940a.

Ikebe, 1942.

Inanami, 1940b, 1940c, 1042d.

Japiinese Bur. Fish., 1934, 1939.

Kagoshima Pref. Fish. Expt. Sta., 1926b, 1927a, 1928b,
1929b, 1930b, 1930c, 19311), 1932b, 1933b.

Kanamura and Imaizumi, 1935.

Kimura, 1942a.

Mie Pref. Fish. Expt. Sta., 1930c, 1930e.

Nakamura, 1949.

Oita Pref. Fish Expt. Sta., 19,30.

Okinawa Pref. Fish. Expt. Sta., 1940b.

Omori and Fujimoto, 1940.

Omori and Fukuda, 1938, 1940.

South Seas Govt.-Gen. Fish. Expt. Sta., 1942.

Takao Prov. Fish. Expt. Sta., 1927.

Takayama and Ando, 1934.

Uehara, 1941.
Fishing conditions correlated with weather

Kanamura and Imaizumi, 1935.

Oita Pref. Fish. Expt. Sta., 1930.
Food

Kishinouye, 1917b, 1923.

Nakamura, 1943, 1949.
Habits

Kishinouye, 1923.

Nakamura, 1949.
Keys

Godsil and Byers, 1944.

Kishinouye, 1915a, 1923.

Nakamura, 1949.
Measurement data

Godsil and B.vers, 1944.

Higashi, 1940a, 1941c.

48

FISHERY BULLEmN" OF THE' FISH ANOi WILDLIFE. SERVICE

Parathunnus mebachi — Continued
Measurement data — Continued

Ikebe, 1040a.

Kanamura and Imaizumi, 1935.

Oita Pref. Fish. Expt. Sta., 1925, 1927a, 1927b, 1930.

Watanabe, H., 1940.
Meristic characters

Godsil and Byers, 1944.
Migration

Kochi Pref. Fish. Expt. Sta., 1923b, 1924.

Nakamura, 1943.
Parasites

Kishinouye, 1923.
Reproduction

Nakamura, 1943.
Sexual maturity

Kanamura and Imaizumi, 1935.
Synonymy

Kishinouye, 1923.

Nakamura, 1939b, 1949.
Young

Hatai et al., 1941.

Kishinouye, 1926.
Young as food of tunas

Kishinouye, 1917b.
Parathunnus siM
Anatomy

Su.vehiro, 1941, 1942.
Chemical analysis

Mi.vama and Osakabe, 1938.
Classification

Okada and Matsubara, 1938.
Common names

Jordan and Hubbs, 1925.

Jordan and Snyder, 1901.

Okada and Matsul>ara. 1938.

Shapiro, 194Sb.

Tinker, 1944.

TJlrey and Greeley, 1928.
Compared with Pelamys sibi

Bleeker, 1879.
Compared with Thynnus alalonga

Temminck and Schlegel, 1850.
Description

Brock, 1949.

Fowler, 1927, 1928.

Jordan and Evermann, 1926b.

Jordan and Hubbs, 1925.

Jordan and Jordan, 1922.

Okada and Matsubara, 1938.

Temminck and Schlegel, 1850.

Tinker, 1944.
Distribution

Domantay, 1940.

Fowler, 1927, 1928, 1929, 1931, 1938, 1949.

Herre, 1940.

Jordan and Evermann, 1926a, 1926b.

Jordan and Hubbs, 1925.

Jordan and Jordan, 1922.

Jordan and Snyder, 1901.

Paratlunmus sibi — Continued
Distribution — Continued

Okada and Matsubara, 1938.

Richardson, 1846.

Shapiro, 1948b.

Smith and Schaefer, 1949.

Snyder, 1904.

Tanaka, 1931.

Tinker, 1944.

Ulrey, 1929.

Ulrey and Greeley, 1928.
Distribution correlated with water temperature

Uda, 1935a.
Figured

Domantay, 1940.

Fowler, 1927, 1928.

Jordan and Evermann, 1926b.

Kitahara, 1897.

Temminck and Schlegel, 1850.

Tinker, 1944.
Pood

Suyehiro, 1942.
Habits

Brock, 1949.
Hormones

Toyama et aL, 1941.
Keys

Brock, 1949.

Jordan and Evermann, 1926b.

Okada and Matsubara, 1938.
Measurement data

Brock, 1949.

Higashi, 1942.
Synonymy

Fowler, 1928, 1949.

Jordan and Evermann, 1926b.

Jordan and Hubbs, 1925.

Richardson, 1846.

Tanaka, 1931.

Ulrey and Greeley, 1928.
Young as food of tunas

Marukawa, 1939.
Paraihynnus sibi. See Parathunnus sibi.
Pelamys afflnc. See Euthynnus alletteratus.
Pelamys macropterus. See Neothunnus macropterus.
Pelamys pelamys. See Katsuwonns pelamis.
Pelamys sibi

Compared with Thynnus sibi

Bleeker, 1879.
Pelamys thunnina. See Euthynnus alletteratus.
Plecostei
Anatomy

Berg, 1947.

Kishinouye, 1917a.

Takahashi, 1924.
Classification

Berg, 1947.

Kishinouye, 1917a.

Takahashi, 1924, 1926.

BIBLIOGRAPHY ON PACIFIC TUXAS

49

Populations
Alkawa, 1937.
Brock, 194;{.
Clark, 1929.
Goilsil, 1948. 1949.
Godsil and Byers, 1944.
Imamura, 1949.

Tauchi, 1940a, 1940b. 1940c, 1941.
Tominaga, 1943.
Uda and Tokunaga, 1937.
Uda and Tsukushi, 1934.

Reproduction
Brock, 1943.

Delsman and Hardenburg, 1934.
Eckles, 1949b.
Hatai et al., 1941.
Ikebe, 1941b.
Imamura, 1949.
Kishinouye, 191.5a, 1923.
Marr, 194S.

Nakamura. 1938, 1939b, 1943, 1949.
Schaefer, 194Sc.
Schaefer and Marr, 1948a.
Serveuty, 1941, 1942a.
Shapiro, 1948b.
Soc. Prom. Ocean. Fish., 1936.
Tinker, 1944.
Walford, 1937.
Watanabe, H.. 1939.
Whitehead, 1931.
Tabe and Mori. 1948.

Salinity. See also Oceanographic conditions.
Correlated with fishing

Inanami, 1941.

Uda and Tokunaga, 1937.
Scomber taso. See Auxis taso.
Semathunnus

Compared with yeothunnus

Fowler, 1933.

Nakamura, 1939a.
Semaihuntius guildi

Compared with Ncothunnus macropterus

Nakamura, 1939b.
Description

Fowler, 1933.
Distribution

Fowler, 1934.
Synonymy

Fowler, 1934.
Semathunnus itosibi
Common names

Tinker, 1944.
Description

Tinker, 1944.
Distribution

Fowler, 1934.

Tinker, 1944.
Synonymy

Fowler, 1934.

Sex. See Morphometries.
Sexual maturity. See Maturity.
Size composition

Aikawa, 1937.

Aikawa and Kate, 1938.

Brock, 1943.

Hart et al., 1948.

Inanami, 1942b.

Kagoshima Pref. Fish. Expt. Sta., 1937.

Kawana, 1934.

Kida, 1936.

Kimura. 1932, 1935, 1941, 1942a.

Mine and lehisa, 1940.

Nakamura Res. Staff, 1949.

Okamoto, 1940.

Sasaki, 1939a, 1939b.

Scagel, 1949.

Schaefer, 1948b.

Schaefer and Marr. 1948a.

Serventy, 1941, 1947.

Tauchi, 1940a, 1940b, 1940c.

Uda, 1935b.

Uda and Tsukushi, 1934.

Yabe and Mori, 1948.
Skipjack. See Katmiu-onus pelamis.
Skipjack, black. See Euthynnus spp.
Spawning. See Reproduction.
Specific gravity

Correlated with fishing

Formosa Govt.-Gen. Fish. Expt. Sta., 1930, 1931,

1932, 1933b, 1934.
Japanese Bur. Fish., 1939, 1940.
Mie Pref. Fish. Expt. Sta., 1930a, 1930b, 1930c, 1930d,

1930e.
Omori and Fujimoto, 1940.
Omori and Fukuda, 1938, 1940.
Shimamura, 1927.

Taihoku Prov. Fish. Expt. Sta., 1929.
Stock. See Populations.
Stomach contents. See Food.
SuiTival rates

Tauchi, 1940a, 1940b, 1940c.
Synonymy

Bleeker, 1852, 1856.

Boeseman, 1947.

Chevey, 1932a, 1934.

Chu, 1931.

Evermann and Seale, 1907.

FAO, 1949.

Fish, 1948.

Fowler, 1904b, 1928, 1931, 1934, 1938, 1944, 1949.

Fraser-Brunner, 1949, 1950.

Griffin, 1927.

Giinther, 1860, 1876.

Herre, 1936.

Hildebrand, 1946.

Jenkins, 1903.

Jordan, 1923.

Jordan and Evermann, 1896, 1905, 1926b.

Jordan and Gilbert, 1882.

50

FISHERY BUXlrErKEN OF THE FISH ANJ> WILDLIFE SERVICE

Synonymy — Continued
Jordan and Hiibbs, 1925.
Jordan and Starks, 1907.
Jordan, Tanaka, and Snyder, 1913.
Kishinouye, 1923.
Liitken, ISSO.
McCuIloch, 1922.
Meek and Hildebrand, 1923.
Nakamura, 1939a, 1939b, 1949.
Nichols and LaMonte, 1941.
Phillipps, 1927b.
PoweU, 1937.
Richardson, 1846.
Schultz, 1949.
Schultz and DeLacy, 1936.
Serventy, 1942b.
Soldatov and Lindberg, 1930.
Tanaka, 1912, 1931.
Ulrey and Greeley, 1928.
Wade, 1949.
Walte, 1907, 1921.
Weber, 1913,
Whitley, 1937.

Tagging

Anonymous, 1939.

Fukuda and lizuka, 1940b.

Godsil, 1938.

Kagoshima Pref. Fish. Expt. Sta., 1928a, 1936b, 1938b,

1939b, 1940b.
Kawana, 1934.
Matsumoto, 1937.
Seagel, 1949.

South Seas Govt.-Gen. Fish. Espt. Sta., 1941c.
Uda, 1936.
Temperature. See Body temjierature ; Water tempera-
ture ; also Oceanographic conditions.
Thunuidae
Anatomy

Kishinouye, 1917a, 1919a.
Classification

Jordan, 1923.

Kishinouye, 1917a.

Liitken, 1880.
Distribution

Bleeker, 1844.
Keys

Jordan and Hubbs, 1925.
Synonymy

Jordan, 1923.

Lutken, 1880.
Thunniformes. See Plecostei.
Thunnus alalungu. See Thunntis germo.
Thunnus albacora. See Neothunnus macropterus.
Thunnus germo
Age

Aikawa and Kato, 1938.

Brock, 1943.

Ikebe, 1940c.

Kanamura and Yazaki, 1940b.

Kimura, 1942a.

Thunnus germo — Continued
Age — Continued

Tauchi, 1940c.

Uno, 1936b.
Anatomy

Bennett, 1840.

Fish, 1948.

Godsil and Byers, 1944.

Kishinouye, 1915a, 1915b, 1919a, 1922a, 1923.

Nakamura, 1949.

Suyehiro, 1941.
Body condition

Aikawa and Kato, 1938.

Kanamura and Yazaki, 1940b.

Soc. Prom. Ocean. Fish., 1936.
Body temperature

Anonymous, 1938.

Kanamura and Yazaki, 1940b.

Oita Pref. Fish. Expt. Sta.. 1927a.

Seagel, 1949.
Catch per unit of effort

Imaizumi, 1937.

Japanese Bur. Fish., 1939, 1940.

Kanamura and Yazaki, 1940a, 1940b.

Nakamura, 1949.
Chemical analysis

Dill. 1921.

Miyauchi, 1915.

Soc. Prom. Ocean. Fish., 1936.
Classification

Fraser-Brunner, 1950.

Godsil and Byers, 1944.

Kishinouye, 1915a. 1923.

Nakamura, 1939b, 1943. 3949.

Okada and Matsubara, 1938.

Phillipps, 1927b.

Roedel, 1948b.

Shapiro, 1948a.

Soldatov and Lindberg, 1930.

Taranetz, 1937.

Walford, 1931.
Common names

Banihart, 1936.

Craig, 1929.

FAO, 1949.

Fish, 1948.

Fujita and Wakiya, 1915.

Herre and Umali, 1948.

Jordan and Evermann, 1896, 1905.

Jordan and Hubbs, 1925.

Jordan, Tanaka. and Snyder, 1913.

Kishinouye, 1915a, 1923.

Nakamura, 1939b. 1943, 1949.

Okada and Matsubara, 1938.

Phillipps, 1927b.

Roedel, 1948b.

Serventy, 1941.

Shapiro, 194Sa, 1948b.

Smith, 1947.

Starks and Jlorris, 1907.

BIBLIOGRAPHY ON PACIFIC TUNAS

51

Til II II II us germ o — Continued
Common naiups — Continued

Tinker, 1944.

Ulrey and Greeley, 1928.

Walford, 1931, 1937.
Compared with Paratlniiiiiiis mehachi

Roedel, 194Sb.
De.soription

Barnhart, 1936.

Bennett, 1840.

Boeseman, 1947.

Clemens and Wilby, 1946.

Cooper, isa'!.

Cuvier and Valenciennes, 1831.

Fowler, 1904b, 1928.

Fraser-Brunner, 19.o0.

Godsil and Byers, 1944.

Griffin, 1927.

Giinther, ISCO, 1876.

Jordan and Evermann. 1905, 1926b.

Jordan and Hubbs, 192.").

Jordan and Jordan, 1922.

Kisbinouye, 1915a, 1923.

Jleek and Hildebrand, 1923.

Nakamura, 1939b, 1949.

Oka da and Matsubara, 1938.

Roedel, 1948b.

Serventy, 1941.

Shapiro, 1948a.

Soldatov and Lindberg, 1930.

Starks, 1918.

Stead, 1906.

Tinker, 1944.

Walford, 1931, 1937.
Distribution

Anonymous. 1938.

Barnliart, 1936.

Brock, 1939.

Clemens and Wilby, 1946.

Cooper, 18a3.

Cowan, 1938.

Cuvier and Valenciennes, 1831.

Eigenmann, 1892.

Eigenmann and Eigenmann, 1891.

FAO, 1949.

Fisii, 1948.

Fowler, 1904a, 1923b, 1928, 1931, 1938, 1944.

Fraser-Brunner, 1950.

Fujita and Wakiya, 191.5.

Gilbert and Starks, 1904.

Godsil and Greenhood, 1948.

Griffin, 1927.

Giinther, 1860, 1876.

Herre, 1940.

Hildebrand, 1946.

Holder, 1912.

Hubbs, 1928.

Imaizuuii, 1937.

Japanese Bur. Fish., 1939, 1940.

Jordan, 1885.
320179°— 51 5

Thunnus germo — Continued
Distribution — Continued

Jordan and Evermann, 1896, 1905, 1926a, 1926b.

Jordan and Gilbert, 1881a, 1882.

Jordan and Hubbs, 1925.

Jordan and Jordan, 1922.

Jordan and Seale, 1906.

Jordan, Tanaka, and Snyder, 1913.

Kanamura and Yazaki, 194()b.

Klmura, 1942b.

Kishinouye, 1915a, 1923.

Koehi Pref. Fish. Expt. Sta., 1923b, 1924.

Matsubara, 1943.

McCuUoch, 1922.

Meek and Hildebrand, 1923.

Metz, 1912.

Nakamura, 19.39b, 1943, 1949.

Okada and Matsubara, 1938.

Phillipps, 1927a, 1927b.

Phillipps and Hodgkinson, 1922.

Roedel, 1948b.

Roughly, 1916.

Sampson, 1940.

Sehaefer, 1948c.

Schultz and DeLacy, 1936.

Serventy, 1941, 1947.

Shapiro, 1948a, 194Sb.

Soldatov and Lindberg, 1930.

Starks, 1918.

Starks and Morris, 1907.

Stead, 1906, 1908.

Tanaka, 1931.

Taranetz, 1937.

Thompson and Higgins, 1919.

Tinker, 1944.

Ulrey, 1929.

Ulrey and Greeley, 1928.

Walford, 1931, 1937.

Whitehead, 1929.
Distribution correlated with water temperature

Takayama and Ando, 1934.

Uda, 1935a.
Eggs

Watanabe, H., 1939.
Enemies

Bennett, 1840.
Exploitation rates

Tauchi, 1940c.
Figured

Anonymous, 1938.

Barnhart, 19.36.

Clemens and Wilhy, 1946.

Cooper, 1S&3.

Fowler, 1904a.

Fraser-Brunner, 19.50.

Godsil and Byers, 1944.

Griffin, 1927.

Giinther, 1876.

Holder, 1912.

Jordan and Evermann, 1905, 1920b.

52

FISHE'RY BULLEITIN OiF THE* FISH AA^D WILDLIFE SERMCE

Thunnus germo — Oonlinued
FiKui-fd — Continned

Kishinouye, 1915a, 1923.

Kitahara, 1897.

Nakamura, 1949.

IJoedel, 194Sb.

Serventy, 1941.

Shapiro, 1948a.

Tinker, 1944.

Walford, 1931, 1937.
Fisiiing conditions correlated witli area

Hart and Hollister, 1947.

Hart et al., 1948.
Fisiiing conditions correlated with oceanography

Aikawa, 1933.

Chiba Pref. Fish. Expt. Sta., Katsuura Br., 1936, 1941.

Hart and Hollister, 1947.

Hart et al., 1948.

Inanaml, 1942d.

Japanese Bur. Fish., 1939, 1940.

Kagoshima Pref. Fish. E.xpt. .Sta., 1927a, 1928b, 1930b,
1930c, 1931b, 19.32b, 1932c, l!l33b.

Kanamnra and Yazaki, 1940b.

Ximura, 1942a, 1949.

Mie Pref. l^sh. Expt. Sta., 1930c, 1930e.

Nakamura, 1949.

Sasaki, 1939b.

Scagel, 1949.

Shapiro, 1948a.

Takayama and Ando, 19.34.

Uda, 1940c.

Uda and Tokunaga, 1937.
Fishing conditions correlated wilh season

Hart et al., 1948.
Fishing grounds correlated with oceanography

Soc. Prom. Ocean. Fish., 1936.
Food

Anonymous, 1938.

Asano, 1939.

Bennett, 1840.

Clemens and Wilby, 1946.

Hart and Holli-stor, 1947.

Hart et al., 1948.

Japanese Bur. Fish., 1939, 1940.

Jordan and Gilbert, 18811), 1882.

Kanamura and Yazaki, 1940b.

Kishinouye, 1917b, 1923.

Kuronuma, 1940.

Nakamura, 1943, 1949.

Scagel, 1949.

Shapiro, 1948a.

Starks, 1918.

Starks and Morris, 1907.

Walford, 1937.

Watanabe, H., 1939.
Growth

Aikawa and Kato, 1938.

Brock, 1943.

Kishinouye, 1923.

Thunnus germo — Continued
Habits

Jordan and Gilbert, 1882.

Kishinouye, 1923.

Nakamura, 1949.

Shapiro, 1948a.
Hormones

Toyama et al., 1941.
Keys

Brock, 1949.

Fraser-Brunner, 1950.

Godsil and Byers, 1944.

Hildebrand, 194C.

Jordan and Evermann. 1926b.

Kishinouye, 191."ia, 1023.

McCuUoch, 1922.

Meek and Hildebrand, 1923.

Nakamura, 1949.

Okada and Matsubara, 1938.

Roedel, 194Sb.

Serventy, 1941.

Soldatov and Lindberg, 1930.

Taranetz, 1937.

Walford, 1931, 1937.
Measurement data

Aikawa and Kato, 1938.

Anonymous, 1938.

Brock, 1943.

Godsil, 1948.

Godsil and Byers, 194^.

Ikebe, 1940c.

Japanese Bur. Fish., 1939, 1940.

Kanamura and Yazaki, 1940b.

Oita Pref. Fish. Expt. Sta., 1925, 1927a.

South Seas Govt.- Gen. Fish. Expt. Sta., 1943a.

Uno, 193Cb.

Watanabe, H. 1939.
Meristie characters

Clark, 1929.

Godsil and Byers, 1944.
Migration

Cobb, 1919.

Kimura, 1942b.

Kisliinouye, 1923.

Koclii Pref. Fish. Expt. Sta., 1923b, 1924.

Nakamura, 1943, 1949.

Sasaki, 1939b.

Shapiro, 1948a.

Soc. Prom. Ocean. Fish., 1936.

Walford, 1937.
Populations

Brock, 1943.

Clark, 1929.

Godsil, 194S, 1949.

Godsil and Byers. 1944.

Tauehi, 1940c.

Uda and Tokunaga, 1937.
Reproduction

Brock, 1943.

Nakamura, 1943.

BIBLIOGRAPHY ON PACIFIC TUNAS

53

Th II II II IIS i/crmo — Continued
Reproduction — Continued

Sehaefer, 1948c.

Soc. Prom. Ocean. Fi.sl'., 1936.

Wiilford, 19.37.

WjitanMlic, H., 1939.
Sex ratio

Brook, km:;.

Sexual maturity

Anonymous, 193S.

Clark, 1929.

Kanamura and Yaznki. 1940b.

Soc. Prom. Ocean. Fish.. 1936.

Wataiuibe, H., 19.39.
Size composition

Aikawa and Kato, 1938.

Brock, 1943.

Hart et al., 1948.

Kimura, 1942a.

Sasaki, 19391x

Scagel, 1949.

Tauchi, 1940c.
Survival rates

Tauclii, 1940c.
Synonymy

Boeseman, 1947.

FAO, 1949.

Fish, 1948.

Fowler, 1904b, 1928.

Fraser-Brunner, 1950.

Griffin, 1927.

Giinther, 18G0, 1876.

.Jordan and Evermann, 1896, 1905, 1926b.

Jordan and Gilbert, 1882.

Jordan and Hubbs, 1925.

Jordan, Tanaka, and Snyder, 1913.

Kishinouye, 1923.

MrCulloch, 1922.

Meek and Hildebrand, 1923.

Nakamura, 1939b, 1949.

Phillipps, 1927b.

Schultz and DeLaey. 1936.

Soldatov and Lindberg, 1930.

Tanaka, 1931.

Ulrey and Greeley, 1928.
Tagging

Seagal, 1949.
Young

Kishinou.ve, 1917b, 1919b, 1923.

Liitken, 1880.

Schaefer, 1948c.
Th II II 11 IIS ninccori. See Tliiiiiiiiis iiinccoyi.
'riiiiiiiiiiK iiiacroyi
Catch per unit of effort

Serventy, 1947.
Classification

Itnughly, 1916.
Common names

Serventy, 1941.

Whitley, 1947.

Tliiiiuiiis mucroiji — Continued
Compared with Kiskinoella tonggol

Serventy, 1941.
Description

Castelnau, 1872.

Jordan and Evermann, 1926b.

Macleay, ISSl.

Roughly, 1916.

Serventy, 1941.

Stead, 1908.
Distribution

Jordan and Evermann, 1926b.

Lord, 1927.

Macleay, 1881.

McCulloch, 1922.

Roughly, 1916.

Serventy, 1941, 1947.

Stead, 1908.

Waite, 1928.

Whitley, 1947.
Figured

McCulloch, 1922.

Roughly, 1916.

Serventy, 1941.
Habits

Roughly, 1916.
Keys

Jordan and Everniaiui, 1926b.

McCulloch, 1922.

Serventy, 1941.
Length-weight relation

Serventy, 1941.
Migration

Serventy, 1941.
Reproduction

Serventy, 1941.
Size composition

Serventy, 1941. 1947.
Synonymy

Joi'dan and Evermann, 192Gb.

McCulloch, 1922.
Thiiiiniis ma<-r<ipicnis. See Neothuiiniis macropterus.
Thunniis maciilatus
Distribution

Holder, 1912.
Figured

Holder, 1912.
Thiuiiiiis mebdclii. See I'lirathiiiinus tnebachi.
Thunnus nicolsmii
Compared with KishiiiinJUi loiir/r/ol

Serventy, 1942b.
Til II II II 11.1 ohesus. See also Ptiiulliiiunus iiiehachi and I'ara-

thininus sibi.
Clas.sification

Fraser-Brunner, 19.50.
Doiscription

Fraser-I'.runner, 1950.
Distribution

Fraser-Brunner, 1950.

54

FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE

ThmDiiis obesiis — Continued
Figured

Fraser-Brunner, 1950.
Keys

Fraser-Brunner, 1950.
Synonymy

Fraser-Brunner, 1950.
Thunints orientalis
Age

Aikawa and Kato, 1938.
Kiraura, 1935.
Tauchi, 1940a.
Anatomy

Kishinouye, 1915a, 191!jb, 1919a, 1921, 1022a, 1923.
Migita and Arakawa, 1948.
Nakamura, 1938, 1949.
Suyeliiro, 1942.
Body condition

Aikawa and Kato, 1938.
Body temperature

Olta Pref. Fisli. Expt. Sta., 1927a, 1930.
Chemical analysis

Miyama and Osakabe, 1938, 1940.
Miyauchi, 1915.
Shimizu, 1947.
Classification

Kisliinouye, 1915a, 1923.
Nakamura, 1939b, 1043. 1949.
Okada and Matsubara, 1938.
Shapiro, 1948a.
Common names

Fu.iita and Wakiya, 1915.
.Jordan and Hubbs, 1025.
Jordan and Snyder, 1001.
Kishinouye, 1915a, 1023.
Nakamura, 1939b, 1043. 1949.
Okada and Matsubara, 1938.
Shapiro, 1048a, 1948b.
Tinker, 1944.
Compared with Thunnns thynnus
Kisliinouye, 1021.
Soc. Prom. Ocean. Fish., 1936.
Tinker, 1944.
Description
Boeseman, 10

Jordan and Evermann, 1926b.
Jordan and Hubbs, 1025.
Jordan and Jordan, 1922.
Kishinouye, 1015a, 1923.
Nakamura, 1930b, 1949.
Okada and Matsubara, 1938.
Shapiro, 104Sa.
Temminck and Schlegel, 1850.
Tinker, 1044.
Distribution
Fowler, 1034.
Fujita and Wakiya, 1015.
Jordan and Evermann, 1026a, 1926b.
Jordan and Hubbs. 1925.
Jordan and Jordan, 1922.

Th u n n us or en talis — Continued
Distribution — Continued

Jordan and Snyder, 1000, 1001.
Kimura, 1042h.
Kishinouye, 1915a, 1023.
Kochi Pref. Fish. Expt. Sta.. 1024.
Mat.subara, 1943.
Mori, 1928.

Nakamura, 1038, 1930h, 1943, 1949.
Okada and Matsubara, 1038.
Reeves, 1928.
Richardson, 1846.
Shapiro, 1948a, 1048b.
Tinker, 1944.
DistriI)ution correlated with water temperature

Takayama and Ando, 1034.
Eggs

Hatai et al., 1041.
Nakamura, 1938, 1949.
Enemies

Kishinouye, 1928.
Exploitation rates

Tauchi, 1940a.
Figured
Kishinouye, 1915a, 1923,
Naliamura, 1939b, 1040.
Otaki, Fujita, and Higurashi, 1003.
Shapiro, 1948a.
Tinker, 1044.
Fishing conditions correlated with astronomical
phenomena
Kawana, 1034.
Fishing conditions correlated with oceanography
Aikawa, 1033.
Fukuda and lizuka, 1040a.
lehisa, 1030.

Kagoshima Pref. Fish. Expt. Sta., 1927a, 1930c, 1932b.
Kawana, 1934, 1037.
Mie I'ref. Fish. Expt. Sta., 1930c, lO.SOe.
Oita Pref. Fish. Expt. Sta., 1030.
Okinawa Pref. Fish. Expt. Sta., 1940b.
Omorl and Fujimoto, 1940.
Omori and Fukuda, 1938, 1940.
Shapiro, 104Sa.
Takayama and Ando, 1934.
Uda, 1940c.
Fishing conditions correlated with weather

Oita Pref. Fish. Expt Sta., 1930.
Food

Kishinouye, 1023.
Nakamura, 1043, 1949.
Shapiro, 104Sa.
Suyehiro, 1042.
Growth

Aikawa and Kato, 1938.
Kimura, 1932. ^

Kishinouye, 1923.
Habits

Kishinouye, 1923.
Nakamura, 1049.
Shapiro, 194Sa.

BIBLIOGRAPHY ON PACIFIC TUNAS

55

Thunniis orentalis — Continued
Hormones

Migita and Arakawa. 1948.

iirock, 1949.

.Ionian and Evermann. 1926b.

Kishinouyp, lltl.-)a. 1923.

Nakamura, 1!)49.

Okada and Matsubara, 1938.
Me.-isiirement data

Aikawa and Kato, 1938.

Higashi, 1040a.

nita Pref. Fish. Expt. Sta., 1927a, 19,30.
Migration

Kimura, 1942b.

Kishinoiiye, 1923.

Kochi Pref. Fisli. Expt. Sta., 1924.

Nakamura, 1943, 1949.

Shapiro, 1948a.
Populations

Tauchi, 1940a.
Reproduction

Hatai et al., 1941.

Kishinouye, 191.5a, 1923.

Nakamura, 1938, 1939b, 1943, 1949.

Soc. Prom. Ocean. Fish., 1936.
Sexual maturity

Hatai et al., 1941.

Nakamura, 19.38.
Size composition

Aikawa and Kato. 1938.

Kawana, 1934.

Kimura, 1932, 193.5.

Jline and lehisa, 1940.

Tauchi, 1940a.
Survival rates

Tauchi, 1940a.
Synonymy

P>oeseman, 1947.

Fowler, 1934.

Jordan and Evermann, 1926b.

Jordan and Hubbs, 1925.

Kishinouye, 1923.

Nakamura, 1939b, 1949.

Richard.«on, 1846.
Tagging

Kawana, 1934.
Young

Kishinouye, 1919b, 1923.
TlniiDuis phillippsi
Classification

Phillipps. 1927b.
Common names

Phillipps, in27b.
Description

Jordan and Evermann. 1926b.
Distribution

Jordan and Evermann, 1026b.

Phillipps, 1927b.
Figured

Jordan and Evermann, 1926b.

ThunnuH orentalis — Continued
Keys

Jordan and Evermann, 1926b.
Synonymy

Phillipps, 1927b.
Tliinnnis pltiltipHi. See Thunnvs phillippsi.
Thiititius rants. See Neothunnus rarus.
Thinirius siilirns
Common names

Craig, 1929.
Description

Jordan and Evermann, 102Gb.
Dlstriliution

Jordan and Evermann, 1026b.

Ulrey, 1020.
Figured

Jordan and Evermann, 1026b.
Keys

Jordan and Evermann, 1926b.
Thunnus schlegeli. See Thunnus orirntalis.
Thtinrnis tkunninn. See Euthynnus allHteratus.
Thunnus thunnus. See Thunnus thynnus.
Thunnus thynnus
Anatomy

Fish, 1948.

Godsil and Byers, 1944.

Kishinouye, 1921.
Catch -per unit of effort

Whitehead, 1931.
Chemical analysis

Dill, 1921.
Classification

Fraser-Brunner, 1950.

Godsil and Byers. 1944.

Roedel, 194Sb.

Soldatov and Lindberg, 1930.

Taranetz, 1937.

Walford, 1931.

Whitehead, 1931.
Common names

Barnhart, 1936.

FAO, 1949.

Fl.sh, 1948.

Jordan and Evermann, 1896.

Jordan, Tanaka, and Snyder, 1913.

Roedel, 194Sb.

Schultz, 1949.

Starks and Morris, 1907.

Tinker, 1944.

Ulrey and Greeley, 1928.

Walford, 1931, 1937.
Compared with Xrothunnus macropterus

Thompson and Higgins, 1919.
O^unpared with Thunnus orientalis

Bashinouye, 1021.

Soc. Prom. Ocean. Fish., 1936.

Tinker, 1944.
Description

Barnhart. 1036.

Fowler, 1028, 1944.

Fraser-Brunner, 1950.

56

FISHERY BULLEimsr OF THE FISH ANjy WILDLIFE SER\^OE

Thunnus thynnus — Continued
Description — Continued

Godsil and Byers, 1944.

Giinther, 1876.

Jleek and Hildebrand, 1923.

Roedel, 194Sb.

Soldatov and Lindberg, 1930.

Stark.s, 191S.

Stead, 1906.

Tinker, 1944.

Walford, 1931, 1937.
Distribution

Abe, 1939.

Barnhart, 1936.

Brock, 193S.

FAO, 1949.

Fish, 1948.

Fowler, 1923a, 1923b, 1928, 1929, 1931, 1934, 1938,
1944.

Fraser-I'runner, 19.50.

Gilbert and Starks, 1904.

Giinther, 1876.

Herre, 1936, 1940.

Hildebrand, 1946.

Holder, 1912.

Jordan and Evermann, 1896.

Jordan and Jordan, 1922.

Jordan, Tanaka, and Sn.vder, 1913.

Meek and Hildebrand, 1923.

Metz, 1912.

Roedel, 1948b.

Schultz, 1949.

Schultz and DeLacey, 1936.

Soldatov, 1929.

Soldatov and Lindberg, 1930.

Starks, 1918.

Starks and Morris, 1907.

Stead, 1906.

Tanaka, 1931.

Taranetz, 1937.

Tinker, 1944.

Ulrey, 1929.

Ulrey and Greeley, 1928.

Waite, 1921.

Walford, 1931, 1937.

Whitehead, 1929, 1931.
Distribution correlated with water temperature

Uda, 1935a.
Enemies

Tinker, 1944.

Walford, 1937.
Figured

Barnhart, 1936.

Fraser-Brunner, 1950.

Godsil and Byers, 1944.

Holder, 1912.

Kitahara, 1897.

Roedel, 1948b.

Soldatov and Lindberg, 1930.

Starks, 1918.

Tinker, 1944.

Th iiiDiiis thynnus — Continued
Figured — Con t i nued

Walford, 1931, 1937.

Whitehead, 1931.
Fishing conditions correlated with oceanography

Kida, 1936.
Food

Tinker, 1944.

Walford, 1937.
Habits

Kida, 1936.

Uchida, 1923.
Keys

Brock, 1949.

Fraser-Brunner, 1950.

Godsil and Byers, 1944.

Hildebrand, 1946.

Meek and Hildebrand, 1923.

Roedel, 194Sb.

Soldatov and Lindberg, 1930.

Taranetz, 1937.

Walford, 1931, 1937.
Measurement data

Godsil and Byers, 1944.

Uda, 1932.
Meristic characters

Godsil and Byers, 1944.
Migration

Wliitehead, 1931.
Populations

Godsil and Byers, 1944.
Reproduction

Tinker, 1944.

Walford, 1937.

Whitehead, 1931.
Size composition

Kida, 1936.
Synonymy

FAO, 1949.

Fish, 1948.

Fowler, 1928, 1934, 1944.

Fraser-Brunner, 1950.

Giinther, 1876.

Herre, 1936.

Jordan and Evermann, 1896.

Jordan, Tanaka, and Snyder, 1913.

Meek and Hildebrand, 1923.

Sclniltz, 1949.

Schultz and, DeLacy, 1036.

Soldatov and Lindberg, 1930.

Tanaka, 1931.

Ulrey and Greeley, 1928.

Waite, 1921.
Thunnus tonf/ffol
Classitication

Fraser-Brunner, 1950.
Compared with Kishinoclla tonggol

Serventy, 1942b.
Description

Bleeker, 1852.

BIBLIOGRAPITi' ON PACIFIC TUNAS

57

Thiinniis ionggol — Continued
Description — Continued
Fraser-Brunner, lOriO.
Giinther, ISGO.
Distribution

Bleeker, 1852. lS61b.
Fraser-Brunner, 1950.
Gunther, 1S60.
Figured

Fraser-Brunner, 1950.
Serventy, 10-42b.
Keys

Fraser-Brunner, 1950.
Synonymy
Bleeker, 1852.
Fraser-Brunner, 1950.
Giinther, 1860.
Thiiiiniin zacnllex. See KishiiioeUa xticalles.
'I'hiDinus. See Thiiiinidiie.
Tliiniiiiis afpnis. See EiithiitniKs allcttcrntiis.
Thiinnus alaloiiyn. See also Tliiinnux girmo.
Compared with TliininuK sihi
Temminck and Soldegel, IS.jO.
Thtjrmus gcrmo. See Thunnus germo.
Thynmis mnccoyi. See Thunnus marroyi.
Thynnus macropterus. See Neotlnnntux mncropierus.
'I'hynnus oricnialis. See Thunnus orienfulis.
Tliyiuius pacificus. See Thunnus gcrmo.
Thynnus pelamys. See Knisuiconus pclnmis.
Thynnus silii. See Pamthunnus sihi; also Thunnus

gcrmo.
Thynnus thunina. See Euthynnus allettcratus.
Thynnus thiinnina. See Euthynnus allettcratus.
Thynnus thynnus. See Thunnus thynnus.
Tliynnus tonggol. See Thunnus toni/gol.
Tides. See also Oeeanographic conditions.
Correlated with fishing
Takao Prov. Fish. Expt. Sta., 1927.
Transparency, water. See Water transparency ; also

Oeeanographic conditions.
Tuna

Bibliography

Corwin, 19.30.
Chemical analysis
Kodama, lizuka, and Harada, 1934.
Tomiyama, 19.3.3.
Common names
Australian

Serventy, 1941.
Wliitley, 1947.
Kngllsh

Barnhart, 1936.

Craig, 1929.

Fish, 1948.

Herre and Uniali, 1948.

Jordan and Evermann, 1896.

Kumata et al., 1941.

Nichols and I.aMonte, 1941.

Roedel, 194Sb.

Schultz, 1949.

Starks and .Morris. 1907.

Tuna — Continued

Couunoii nanie.s — Continued
English— Continued

Tanaka, 1912.

Tinker, 1944.

Ulrey and Greeley, 1928.

Walford, 1931, 1937.
European

Kumata et al., 1941.

Tinker, 1944.
Hawaiian

Jordan and Kvermann, 1905.

Jordan ami .Jordan, 1922.

Smith, 1!)47.

Tinker, 1944.
Indo-Chinese

Chevey, 1932a.
Japanese

Fish, 1948.

Fujita and Wakiya, 1915.

Jordan and Evermann, 1926b.

Jordan and Hubbs, 1925.

Jordan and Jletz, 1913.

Jordan and Snyder, 1901.

Jordan, Tanaka, and Snyder, 1913.

Kishiiiouye, 191."a, 1923.

Kumiita et al.. 1941.

Nakamura. 19.391). 1943, 1949.

Okad.i and Matsubara, 1938.

Shapiro, 194Sa.

Tanaka, 1912.

Tinker, 1944.

Tomiaaga. 1943.
Malayan

Delsniau and Ilardenbur^, 1934.

Kumata et al., 1941.
Maori

Phillipps, 1927b.
Mieronesian

Smith, 1947.
New Zealand

PhilUpps, 1927b.
Peruvian

Nichols and Murphy, 1922.
Philippine

Herre and Umali. 1948.
Ryukyuan

Shapiro, 1948b.
Venezuelan

Schultz, 1949.
Worldwide

FAO, 1949.
Distribution

Hasegawa, 19.37.

South Seas Govt.-Gen. Fish. Expt. Sta., 1937b, 1941a.
Food

Kishinouye, 1895, 1915a.
Habits

Kishinouye, 191.'5a.
Measurement data
Kodama, lizuka, and Harada. 19.34.

58

FISHERY BULLETIN OF THE FISH AJXD WILDLIFE SERVICE

Winidcrer wallisi
Classification

Whitley, 1937.
Compared with Euthynnus allittcratus

Whitley, 1937.
Compared with Eutliynnus yaito

Whitley, 1937.
Description

Whitley, 1937.
Food

Whitley, 1937.
Synonymy
Whitley, 1937.
Water. See also Oceanosraphlc conditions.
Color correlated with fishing
luanami, 1940c.

Taihoku Prov. Fish. Expt. Sta., 1929, 1932.
Temperature

Correlated with body temperature
Nakamura, 1941.

Oita Pref. Fish. Expt. Sta., 1927a, 1930.
Correlated with distribution
Takayama and Ando, 1934.
Takayama, Ikeda, and Ando, 19.34.
Correlated with fishing conditions
Aikawa, 1933.
Chiba Pref. Fish. Expt. Sta., Katsuura Br., 1936,

1937, 193S, 1941.
Formosa Govt.-Gen. Fish. Expt. Sta., 1930, 1931,

1932, 1933b, 1934.
Fukuda and lizuka, 1940a.
Hart and HoUister, 1947.
Hart et al., 1948.
lehisa, 1939.
Inanami, 1941, 1942d.
Japanese Bur. Fish., 1934, 1939, 1940.
Kagoshima Pi-ef. Fish. Expt. Sta., 1925, 1926a,
1926b, 1927a, 1927b, 192Sa, 192Sb, 1929a, 1929b,
1930a, 1930b, 1930c, 1931a, 1931b, 1932a, 1932b,
1932c, 1933a, 1933b, 1935, 1936a, 1937.
Kanamura aud Yazaki, 1940a.
Kawana, 1937.
Kida, 1936.

Kimura, 1941. 1942a, 1949.
Kimura and Ishii, 1933.
Kumamoto Pref. Fish. Expt. Sta., 1946.
Mie Pref. Fish. Expt. Sta., 1930a, 1930b, 1930c,

1930d, 1930e.
Okinawa Pref. Fish. Expt. Sta., 1940a, 1940b, 1943.
Omori and Fujimoto, 1940.
Omori and Fukuda, 1938, 1940.
Sasaki, 1939a, 1039b.

Shizuoka Pref. l"ish. Expt. Sta., 1936, 1937.
South Seas Govt.-Gen. Fish. Expt. Sta., 1942, 1943b.
Taihoku Pi-ov. Fish. Expt. Sta., 1929, 1932.
Takayama and Ando, 1934.
Takayama, Ikeila, and Ando, 1934.
Uda, 1935a, 1935h, 1936, 1938, 1939, 1940b, 1940c.
Uda and Tokunaga, 1937.

Water — Continued

Temperature — Continued

Correlated with fishing conditions — Continued
Uehara, 1941.
Yabe and Mori, 1948.
Transparency correlated with fishing

Inanami, 1942a.

Japanese Bur. Fish., 1934.
Weather

Correlated with fishing

Formosa Govt.-Gen. Fish. Expt. Sta., 1933a.

Hiratsuka and Imaizumi, 1934.

Hiratsuka and Ito, 1934.

lehisa, 19.39.

Kanamura and Imaizumi, 1935.

Oita Pref. Fish. Expt. Sta., 1930.

Okinawa Pref. Fish. ExiJt. Sta., 1940a, 1943.

Okunia, Imaizumi, and Maki, 1935.

Taihoku Prov. Fish. E.xpt. Sta., 1927a, 1927b.

Uda and Watauabe, 1938.

Yellow-finned tuna. See Neothunnus macropterus.
Young

As food of tunas

Eckles, 1949b.

Kishinouye, 1917b.

Marukawa, 1939.
Description

Delsman, 1931.

Delsman and Hardenburg, 1934.

Eckles, 1949b.

Giinther, 1889.

Kagoshima Pref. Fish. Expt. Sta., 1926a, 1927b.

Kishinouye, 1919b, 1923, 1924, 1926.

Liitken, 1880.

Marr, 1948.

Schaefer and Marr, 194Sa, 1948b.

Wade, 1949.
Figured

Eckles, 1949b.

Giinther, 1889.

Kishinouye, 19191i, 1923, 1926.

Liitken, 1880.

Schaefer and Marr, 1948a, 194Sb.

Wade, 1949.
Records of capture

Delsman, 1931.

Delsman and Hardenburg, 1934.

Eckles, 1949b.

Giinther, 1889.

Hatai et al., 1941.

Inanami, 1942c.

Kagoshima Pref. Fish. Expt. Sta.. 1926a, 1927b.

Kishinouye, 1919b, 1923, 1924, 1926.

Liitken, 1880.

Marr, 1948.

Schaefer, 1948c.

Schaefer and Marr, 1948a, 1948b.

Wade, 1949.

Yabe and Mori, 1948.

O

UNITED STATES DEPARTMENT OF THE INTERIOR, Oscar L. Chapman, Secretary
FISH AND WILDLIFE SERVICE, Albert M. Day, Director

BREEDING HABITS OF LAKE TROUT

IN NEW YORK

By William F. Royce

FISHERY BULLETIN 59

From Fishery Bulletin of the Fish and Wildlife Service

VOLUME 52

JNITED STATES GOVERNMENT PRINTING OFFICE • WASHINGTON 1951

?or sale by the Superintendent of Documents, V. S. Government Printing Office, Washington 25, D. C.- Price 20 cents

CONTENTS

Page

Sexual dimorphism 59

Spawning habits 61

Age and size at maturity 61

Time of spawning 62

Duration of spawning period 65

Place of spawning 66

Spawning act 68

Environment and development of eggs and larvae 70

Efficiency of fertilization 70

Temperature requirements 71

Effects of predation 71

Development of eggs and alevins 72

Juvenile lake trout of Keuka I^ake 73

Summary 74

Acknowledgments 75

Literature cited 75

BREEDING HABITS OF LAKE TROUT IN NEW YORK

By William F. Royce, Fishery Research Biologist

The several races of lake trout (Salcelinus
[ = Cristii'omer] namaycush) are widely sought in
all the more accessible parts of their range. In
tlie Great Lakes, where this species is one of the
most valued food fishes, it is the object of a major
fishery. In smaller lakes of the northeastern
I'nited States and southern Canada, where com-
mercial fishing usually is prohibited, it is sought
as a game fish.

This popularity has been accompanied by
severe declines in the populations of lake trout in
some lakes, notably the Great Lakes. Detailed
knowledge of the species, particularly of the eggs,
larvae, and juveniles below the sizes commonly
caught, is needed for devising measures to prevent
such declines, and for successfully introducing
this desirable species in additional lakes.

Almost nothing is known of the habits of young
lake trout, probably because of their deep-water
habitat ; in fact, very few wild lake trout less than
8 inches long have even been seen. The re-
productive habits of the species have been im-
perfectly known, and very little has been published
on size and age at maturity. Accordingly, a
study of the breeding habits of this species and
the life history of its young was made in 1939,
1940, and 1941, on several lakes in the State of
New York.

SEXUAL DIMORPHISM

The lake trout, unique among the salmon family,
lacks almost completely the malformed jaws or
kype common to mature males of other species.
Examination of several hundred lake trout from
various lakes in New York State showed that it is
almost impossible to distinguish the sex of mature
lake trout by examination of the head alone. The
males have only a slight tendency toward a more
j pointed snout — although J. R. Westman reported
in a personal communication that he had seen a verv

Note.— This paper is a revision of a thesis that was submitted to Cornell
I'niversity in 1943 in partial fulfillment of the requirements for the depree
of doctor of philosophy.

large male lake trout from Lake Simcoe, Ontario,
with a well-developed kype.

It is pertinent to compare the jaws of the lake
trout with those of the Pacific salmon, in which
the kype attains its maximum development.
The Pacific salmon migrate enormous distances
to the spawning ground and live entirely on stored
food for almost a year before spawning. Mottley
(1936) ' suggests that the development of the kype
in the male may occur because its demand on the
material mobilized for the development of the
gonads differs from that of the female. He
postulates that the ovaries would have a general
requirement for stored materials, while the testes
would require little albuminoid or fat. Thus,
these materials might be utilized in the growth of
the kype instead of being excreted.

The lake trout would appear to be a diametric
opposite. It rarely has a kype, migrates only the
short distance from the deep to the shoal waters
of a lake, and feeds up to and through the spawning
period.- Inasmuch as the lake trout does not ac-
quire a kype and as the maturation of the gonads
parallels that of the salmon, Mottley's suggestion
leaves some things to be explained. Possibly,
since the lake trout feeds right up to and through
the spawning season, the gonads can develop from
ingested food instead of mobilizing stored material
from the body.

Alike in external structure, male and female
lake trout are also very similar in color when
removed from the water. However, in New York
State, the normal coloration of both sexes varies
widely from lake to lake. The lake trout of the
large, clear Finger Lakes are light olivaceous,
almost silvery on the back and sides, with a little
yellow or orange in the fins. There are all grada-
tions between the color of these trout and the very
dark trout of the brown-water Adirondack lakes.

I Publications referred to parenthetically by dale are listed in Literature
Cited, p. 75

' Rayner (194 1) found that stomachs of ripe lake trout taken on the spawn-
ing area contained fish, lake-trout eftRS, and miscellaneous invertebrates.

59

60

FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE

Figure 1. — Male lake trovit on the spawning grounds in Otsego Lake, N. Y.

LAKE TROUT BREEDING HABITS

61

The latter have stronger colors, and the sexual
differences are a little more pronounced; the males
tend to have more brilliant yellow, orange, and
black in the paired fins than the females. But
even in these lake trout it is not always possible
to distinguish the sexes on the basis of external
differences.

This normal coloration is considerably changed
when the male lake trout are excited on the spawn-
ing area. While they are courting, the chromato-
phores on their backs contract, making the backs
appear decidedly light colored, while the sides,
flooded with pigment, become very lustrous and
almost black (fig. 1). Merriman (1935) observed
this condition in the lake trout of Squani Lake, N . H. ,
and it was seen by the writer in Otsego Lake,
N. Y., in 1940 and 1941, when selected fish were
speared and the brilliant coloration was found to
be restricted to the males. Striking as this colora-
tion was during the courting or spawning, the colors
were most ephemeral. After the fish were netted
or speared, color differences between the sexes
could not be detected.

SPAWNING HABITS
AGE AND SIZE AT MATURITY

The age analysis, by means of scales, of 33
mature lake trout caught by gill net on the spawn-
ing area oft' Peach Orchard Point in Seneca Lake,
N. Y., showed that 13 had 5 annuli and the remain-
ing 20 had 6 annuli. Comparison of the lengths
of the lake trout in this sample with the length
frequency of 424 lake trout taken during the
spawning season in 1941 showed that these age
groups comprised tlie bulk of the catch, but
probably an appreciable quantity of older fish
wiere taken.

Data collected during 1940 by J. R. Westman
on the lake trout of Lake Simcoe, Ontario, showed
that 13 out of 20 five-year-old and 16 out of 17
six-year-old lake trout were mature. Samples from
Keuka Lake, N. Y., in the same year showed
similar results: 15 out of 18 five-year-old and 5 out
of 6 six-year-old trout were mature. There was
a shght tendency for the greater proportion of
the young males to be mature in these two lakes,
as well as in Seneca Lake.

Fry and Kennedy (1937) estimated, by means
of the modes of a length frequency distribution,
that the lake trout of Lake Opeongo, Algonquin
Park, Canada, reached the minimum age at

maturity in their fifth year of life (corresponding,
presumably, to four annuli). Inasmuch as they
had only five lake trout less than 13 inches long,
and as my observations indicate very small
growth of lake trout in the first year, I believe
that they assigned to each mode an age 1 year
less than it should have been.

These data are substantiated by studies made
on the growth of hatchery-reared trout. Surbcr
(1933) secured eggs from female lake trout, aged
4 years 6 months, whose lengths varied from 18
to 26 inches; but at this time only 10 females
out of somewhat less than 2,000 males and females
spawned, producing an average of only 962 eggs
per female. No data on subsequent spawning
were presented, but certainly the majority of these
fish did not spawn before their sixth year. Surber
considered that this age at maturity was com-
parable to that attained by wild fish. He gave
the length of the trout at the end of their first,
second, third, and fourth years of life as 10, 14,
16 to 18, and 18 to 26 inches, respectively. This
rate of growth in the fii-st and second years of life
is markedly greater than that existing in Keuka
Lake. With this start it is possible that the
hatchery fish spawned earlier than they would in
the wild, which is known to be true of some other
species of hatchery-reared trout, especially brook
trout.

The rapidly growing lake trout of Seneca Lake,
whatever their age, do not mature until they are
26 to 30 inches in total length; those of Keuka
Lake mature at a total length of 18 to 24 inches.
In Skaneateles Lake, N. Y., however, Rayner
(1941) captured many mature lake trout of 15
and 16 inches total length. Fry (1939) reported
that the minimum size at maturity in some lakes
of Algonquin Park, Canada, varied from 14 to 18
inches according to the lake.

Obviously with this variation in size at maturity,
a uniform minimum legal-size hmit of 15 inches,
such as exists in New York State, may permit
the taking of many immature, rapidly growing
fish in some lakes while providing entirely too
much protection in other lakes. It would appear
necessary to consider the growth rate and fishing
pressure in each lake in setting a mmimum size
limit.

Slowly growing lake trout may be subject to
senility at a small size. Fry and Kennedy (1937)
reported that none of the lake trout of more than

62

FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE

22 inches fork length in Lake Opeongo, Algonquin
Park, Ontario, were capable of spawning. Such
widespread inipotency was not observed in any
of the New York lake trout. The conservation
department employees engaged in spawn-taking
operations on the Adirondack and Finger Lakes
reported that only occasionally would an impotent
fish be found. The more limited observations I
made also failed to show any impotency, and it
is quite likely that after the lake trout in New
York State lakes are mature they may spawn
several times before succumbing to the infirmities
of age.

TIME OF SPAWNING *

The available information shows that lake trout,
and most other trout, spawn once a year in the
fall when the temperature is dropping and the
days are becoming shorter. Among different races
of lake trout, small variations in the spawning
date are found. This is true also of the same
race of lake trout in different lakes, and of the
same race in the same lake in different years.
It appears probable that fluctuations in light and
temperature, in the physical characteristics of
different lakes, and in the responses of different
races are the determining factors.

These factors have proved important in in-
fluencing the spawning time of other species.
Hoover and Hubbard (1937) have shown that
brook trout which normally spawned in Decem-
ber could be induced to spawn in late August
and early September by increasing the amount
of light in early spring and decreasing it in late
summer. Bissonette and Burger (1940) state
that "there is no uniform control of the sexual
cycle applicable to all fish. In some fish, tem-
perature seems to be the major factor; in others,
light and temperature play cooperative roles;
while in still others, light appears to be the most
important factor."

Merriman and Schedl (1941), on the basis of
laboratory experiments on the four-spined stickle-
back, Apeltes guadracus (Mitchill), concluded that
light influenced oogenesis but not spermato-
genesis, while temperature somewhat unequally
affected the maturation of the gonads of both
sexes. McCay et al. (1930) concluded on the
basis of feeding experiments that the spawning
time of brook trout could be influenced by the
food supply. They found that the age at ma-

turity could be advanced or postponed by in-
creasing or decreasing the amount of food fed
to the hatchery trout, but the question of chang-
ing the spawning date of mature trout was not
clarified.

After several years of netting lake trout in
Raquette Lake for spawn taking, the hatchery
men of the New York Conservation Department
have observed that the lake trout run earlier
after a sudden drop in temperature. The exten-
sive data on their operations were made avail-
able to me, and weather data were obtained
from the United States Weather Bureau (table 1).

Table 1. — Weather conditions in relation to peak of lake-
trout egg take at Raquette Lake, 1933-41

Year

Air tem-
perature '
(° F.)

Cloudy
days '

Peak of
egg take

1933

56.8
54.9
52.4
54.0
55.0
(')
55.4
53.4
56.6

22
21
24
19
21
(')
18
22
21

Oct. 22

1934

Oct. 18

1935

Oct. 13

1936

Oct. 19

1937

Oct. 21

1938

{')

1939

Oct. 23

1940

Oct. 19

1941

Oct. 19

' Average air temperature for the month of September at nearby Indian
Lake.

' Number of cloudy days in July, August, and September in the northern
plateau region of New York.

3 No eggs taken.

The average air temperature for September
reported by the Indian Lake weather station was
used because it was the nearest station to
Raquette Lake, with complete weather records for
the 8 years of spawning data. The average
number of cloudy days for the entire northern
plateau region of New York was selected because
many of the smaller stations had no automatic
sunshine recorders and their estimates of cloudi-
ness varied considerably. The number of cloudy
days in July, August, and September was used
because the work of Hoover and Hubbard (1937)
indicated that changes in the light required a
considerable time to influence the development
of the eggs, and these 3 months were the ones
preceding the spawning season which had
decreasing amounts of daylight.

The analysis of these data by multiple regres-
sion (table 2) indicated that the date of spawning
was advanced by lower temperatures or a greater
number of cloudy days and retarded by warmer
weather or fewer cloudy days. However, neither
on air temperature alone nor on cloudiness alone

LAKE TROUT BREEDING HABITS

63

was the partial regression of the spawning date
statistically significant. When both factors were
considered in a multiple regression coefficient the
result was significant (7?=. 8643 when R of .836
or greater is to be expected 5 percent of the time
with 5 degrees of freedom).

Table 2. — Reduced data for tnutliple regression analysis of
the date of peak of lake-trout egg take at Raquetle Lake

i, = Avera!;e air temperature for the month of September
at Indian Lake.

i2= Number of cloudy days in July, August, and Septem-
ber in the northern plateau region of New York.

?/=Date of peak of lake-trout egg take.

Number of observations: n = 8

Means:

i, = 54.81 X2 = 21.00 17=10.25

Sums of squares:

&,2= 16.01

Sums of products;
Sj 1X2= -6.80

Sx22 = 24.00 5i/2 = 65.50

Sz2y= -27.00 St,!/ = 23.08

Correlation coefficients:

r,2=-.3469 r,2=-.6810 r„ = .7534

Standard partial regre.ssion coefficients:

B„,.2 = .5675 B„2.,= -.4841

Multiple regression equation:

B= - 80.3 -I- 2.32A',- 1.32X2

Tests of Sionikic^nce:

Standard partial regression coefficients: (DF = 5)

.5675

for B„i 2 (
for B„2 1 ( =

.2398
.4841

= 2.366
= 2.019

.2398
neither significant
Multiple correlation or multiple regression: (DF = b)
/? = .8643 significant

A similar analysis of data on the peak of egg
take from Upper Saranac Lake (tables 3 and 4)
was less conclusive. The date of peak of egg take
in 1941 was about a month later than usual, but
if we omit this aberrant observation the date of
the peak at Upper Saranac Lake seems to bear
the same relation to air temperature and cloudiness
as at Raquette Lake. However, neither the partial
nor the multiple regression coefficients are signifi-
cant. (R=. .699 when R of .930 or greater is to be

expected 5 percent of the time with 3 degrees
of freedom).

Table 3. — Wealher conditions in relation to peak of lake-trout
egg take in Upper Saranac Lake, 1935-41

Year

Air tem-
perature'
(°F.)

Cloudy
days'

Peak of
egg take

52.3
56.9
54.8
52.0
M.g
52.4
57.2

24
19
21
28
18
22
21

Oct. 17

1936

Oct. 23

1937 _

Oct. 21

193g

Oct. 15

1939

Oct. 24

1940

Oct. 26

1941

Nov. 20

I Average air temperature for tlie month of Septemljcr at nearby Tupper
Lake.

' Number of cloudy days in July, .\ugust, and Septemi>er in the northern
plateau region of New York.

Table 4. — Reduced data for the multiple regression anaylsis
of the date of the peak of lake-trout egg take at Upper
Saranac Lake

ii = Average air temperature for the month of September
at Tupper Lake.

i2 = Number of cloudy days in July, August, and Septem-
ber in the northern plateau region of New York.

y=Date of peak of lake-trout egg take.

Number of observations: n = 6 '

Means:

*, = 53.87

Sums of squares:

Sxi2= 19.03

Sums of products:
Si,X2= -28.10

i2 = 22.00 j/ = 21.00
5x2' = 66.00 Si/2 = 90.00
Sx2)/=- 62.00 5x,!/= 19.00

Correlation coefficients:

r,2=-.7929 r,2=-.6263 r„, = .4591

Standard partial regression coefficients:

B„i.2=-1008 B„2.i=--7062

Multiple regression equation:

£:= 50.94 -.219A'i-.825A'2

Tests op Significance:

Standard partial regression coefficients: (Df = 3)

.1008

for B„i.2 < =
for /?„2 1 ' =

6776
7062

= .1488

= 1.0421

6776

neither significant

Multiple correlation or multiple regression: (,DF = S)
ff = .6990 not significant

1941 data omitted.

64

FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE

Other things must be considered in evaluating
these analyses. The data are few, only 6 years in
one instance and 8 in the other, and the Weather
Bureau data on air temperature and cloudiness
cannot be a precise measurement of the tempera-
ture and the light actually affecting the fish.
Furthermore, the period during which the light
and the temperature changes are influential can
only be surmised, and other factors may be
important. For example, in Raquette Lake in
1938 the notably high water level was suspected
of being the cause of almost no lake trout being
caught. However, it was not certain whether this
affected the migrations or prevented the nets from
operating effectively.

Considering that a significant relation was
established in one instance, and that other data
were inconclusive but showed a similar tendency,
it is probable that both light and temperature do
influence the spawning time of lake trout.

Lake trout in Raquette Lake (Oliver R. Kings-
bury, report to the New York Conservation De-
partment, November 1935) spawn at about the
time of the lake turn-over. In the middle of the
1935 spawning season, temperatures taken at the
surface and at depths down to 56 feet revealed
no more than a 3° F. difference between top and
bottom. This seems to be more important than
the actual surface temperature in influencing
spawning, for the surface temperature on the day
the first eggs were taken was 58° F. in 1933, 52° F.
in 1934, and 50° F. in 1935. Merriman (1935)
reports lake trout spawning in Squam Lake, N. H.,
when the surface temperature was 42° F. In
Otsego Lake in 1940 the lake trout were observed
spawning December 5, when the surface tempera-
ture was 37° F. No facilities were available for
taking deep-water temperatures at that time, but
in 1941 the fish were observed late in their spawn-
ing season on December 3, when the water tem-
perature was uniformly 43° F. from the surface
down to 60 feet. These wide variations in surface
temperature indicate its slight value as a deter-
minant of the date of spawning.

Such differences in the progress of cooling in
different lakes are probably associated with the
depths of the lakes, and it appears that the depth
of a lake is associated with the time of lake-trout
spawning. Table 5 presents data from the files of
the New York State Conservation Department on
the time and duration of lake-trout spawn taking

Table 5. — Duration of lake-trout spawn taking operations
by State Conservation Department in some New York
lakes

Year

Date first
eggs r(>
eeived at
hatch-
ery

Date of
peak of
egg take

Date last
eggs re-
ceived at
hatch-
ery

Raquette Lake (alt. 1,762 ft.; max. depth 96
ft.);

1933

1934 ___

Oct. 14
Oct. 14
Oct. 11
Oct. 16
Oct. 16
Oct. 16
Oct. 12
(')

Nov. 5
Oct. 31
Nov. 5
Nov. 2
Nov. 4

(')
Oct. 12

Oct. 13

(')
Oct. 12
Oct. 16

Oct. 17
Oct. 15
Oct. 13
Oct. 10

Oct. 20
Sept. 23
Nov. 20

(')
(»)

('J
P)
(')
(')

Oct. 22
Oct. 18
Oct. 13
Oct. 19
Oct. 21
Oct. 23
Oct. 19
Oct. 19

(')

(')

(')
Nov. 6
Nov. 8

Oct. 14

(')

(')
Oct. 22
Oct. 16
Oct. 21

Oct. 25
Oct. 24

(')
(')

Oct. 24
Oct. 10

Nov. 25

Oct. 17
Oct. 23
Oct. 21
Oct. 15
Oct. 24
Oct. 26
Nov. 20

Oct. 24
Oct. 20

1935

1936 --

Oct. 16
Oct. 21

1937

Oct. 26

1939

Oct. 26

1940

Oct. 24

1941

(')

Lake George (alt. 322 ft.; max. depth 187 ft.):
1928

Nov. 14

1929

Nov. 5

1932

Nov. 13

1936

Nov. 9

1938

Nov. 11

Lake Pleasant (alt. 1,724 ft.; max. depth 53
ft.):

1930

1932

(')
Oct. 15

Sacandaga Lake (alt. 1,724 ft.; max. depth
60 ft.):

1929

Oct. 13

1930

Oct. 26

1932

Oct. 23

1933 ..

Oct. 23

Piseco Lake (alt. 1,661 ft.; max. depth 129 ft.):
1930 . .

Oct. 29

1931 ...

Nov. 5

1932

Oct. 28

1933

Oct. 15

Seventh Lake (alt. 1,786 ft.; max. depth 85
ft.):

1933

Oct. 24

Seneca Lake, (alt. 444 ft.; max. depth 625 ft.):
1939-41 2

Nov. 3

KeukaLake (alt. 709 ft.; max. depth 187 ft.):
1936-39 '

Dec. 3

Upper Saranac Lake (alt. 1,571 ft.: max.
depth 100 ft.):

1935

(=)

1936

(')

1937

(')

1938

0)

1939

m

1940

(')

1941

(')

' Data not available.

Same dates were reported (or each year.

' Data depended on hatchery schedule rather than lake-trout migrations.

operations in some New York lakes. Figure 2,
which incorporates information from table 5, from
Rayner (1941) for Skaneateles Lake, and from my
observations on Otsego Lake, shows this relation
graphically.

It appears that the lake trout spawn early in
the shoal lakes and later in the deep lakes. If, as
indicated previously, they spawn at about the
turn-over time of the lake, this would be expected,
as the deeper lakes cool off more slowly.

Like so many rules, the one that the deeper
the lake the later the lake trout spawn has an out-
standing exception. In Seneca Lake, the deepest
lake in New York State (625 feet maximum
depth), the lake trout spawn the earliest. They
start in late September and continue through
October, spawning in water from 100 to 200 feet

LAKE TROUT BREEDING HABITS

65

10

1 I 1

° 5

-

O OTSEGO L

/

30

-

/

25

-

Okeuka l /

f

JJO

_

/

—

3

/

O SKANEATELES L

t>5

Z

-

/

-

• C

-

/ Ol GEORGE

-

5

—

/

~

30

-

/

-

25

SEVENTH

vCf O PISECO L

-

I 20

O

SACANOfiGA

'7

/ O UPPER SARANAC L
O PAOUETTE L-

-

10

A

^ PLEASANT

5

-

{ 1

SENECA L »

1 t

1 1 1 1 1 1 1 i

1 1 1 1 1 1

z
<
in 5|—

100 20D 300 40^

MAXIMUM DEPTH IN FEET

Fir.iRE 2. — Relation of average date of peak of lake-trout
spawning activity and maximum depth of some New-
York lakes.

deep at a time well in advance of the turn-over
period of the lake. Data taken from September
29 to October 17, 1941, showed that the surface
temperature ranged from 57° to 62° F.

This large deviation in the time of spawning
may be attributed to racial differences in the lake
trout. Milner (1874) gives the spawning time of
the siscowet (Cristmimer namaycush siscowet) as
late August and early September in the deep
waters of Lake Superior. In the same lake the
common lake trout {Salreliniis [ = ('ristimmer]
namaycush) spawns in from 7 feet to 15 fathoms
of water during the month of October and in early
November (Milner 1874, Van Oosten 19:55).
Hubbs (1930) has described the Rush Lake trout
{Cristivomer namaycush huronicus) and states
that it spawns in deep water in late summer rather
than in fall, as does the common lake trout in the
same lake. Dymond (1926) gives the time of
spawning of the common lake trout as the month
of October in Lake Nipigon, Ontario. But he

points out that tliere is a race of black trout in
the same lake which ascends some of the tributary
streams and starts spawning about September 20,
and a third race which is said to spawn in deep
water from October 20 to November 10.

In New York State the spawning data indicate
that two races' of lake trout e.xist: One, the
Seneca Lake trout, spawns early in deep water,
and the other, widespread in the Finger and
Adirondack Lakes, spawns in shallow water at
about the time of the turn-over of the lake.

With these differences in reactions and spawning
habits, it would be desirable to determine if the
Seneca Lake trout can adapt themselves to the
conditions existing in Adirondack Lakes and vice
versa before extensive stocking is attempted.
Lntil such knowledge can be secured it would be
wise to stock lake trout in lakes similar to those
from which the eggs were obtained.

DURATION OF THE SPAWNING PERIOD

Data on the receipt of lake-trout eggs at some
of the New York State hatcheries are summarized
in table 5. The date of receipt of eggs corresponds
closely to the date of take, except for the first
one or two days of the spawning season. Ordi-
narily, only a few ripe fish are found at first,
and if only a few thousand eggs were obtained,
they often were held for a day or two until more
eggs were available to make the trip to the hatchery
worth while. The date the first eggs were taken
probably averages about 1 day earlier than the
date of their receipt at the hatchery. At the
peak of the spawning season the eggs were usually
rushed to the hatchery immediately, so the date
of the peak receipt of eggs corresponds to the date
of the peak egg take.

The tlata in table 5 do not indicate the com-
plete spawning season but rather the season dur-
ing which it was feasible to catch and strip the
trout. High water sometimes so affected the
fishing of the nets that it was not practical to
continue fishing, and bad weather sometimes cut
short the stripping operations. Hence, a short
period of egg take is not necessarily indicative of a

1 other evidence of racial dilTerence is available. New York State fi.sll
hatchery foremen agreed that ckks from Seneca Lake trout averaped ahout
240 an ounce, while egps of lake trout of comparable size from Adirondack
lakes averaeed about 200 to 210 an ounce. No measurements of the actual
diameters of the ecRs were available, but the counts of the hatchery foremen
appeared to be fairly consistent. I). C. llaski'll (unpublished material
gathered in 1941) also reports that th<' Seneca Lake trout grow signifiointly
raster under hatchery conditions than the young laki- trout from Ranuelte
atHi t'pper Saranac Lakes.

66

FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE

short spawning season. It seems likely, however,
that the longer periods of spawn taking closely
approximate the spawning season.

It appears that the lake-trout spawning season
lasts from 10 to 20 clays in the smaller New York
lakes and the duration is fairly uniform in the
same lake from year to year. The lake trout of
Lake George consistently completed their spawn-
ing in 7 to 10 days at the most.

The length of the spawning season increases
in the larger lakes. Van Oosten (1935) gives the
duration of the spawning season in Lake Michigan
as October 10 to November 21; in Lake Huron,
October 10 to November 15; and in Lake Superior,
October 1 to November 6. Seneca Lake is
similar to the Great Lakes in both date and
duration of the spawning season. The earliest
and latest dates on which the New York State
Conservation Department obtained eggs in Seneca
Lake were September 23 and November 3. These
dates are for difTerent years, but the earliest and
latest dates were similar from year to year.

PLACE OF SPAWNING

The observations of Merriman (1935), Royce
(1936), and the writer indicate that lake-trout
spawning areas are restricted to bottom of clean
gravel or rubble, free of sand and mud. As the
fish make no effort to bury the eggs, the bottom
must have crevices into which the eggs can roll,
if eggs and larvae are to be protected.

The location of these suitable areas of bottom
in the lake is primarily determined by currents
or wave action which keep the bottom swept clean.
The lake trout will roll the smaller stones around
and fan oflF the silt, but they cannot remove sand
or mud from the crevices. Any bottom that is
not swept by currents or waves eventually becomes
covered with mud, although in the usual oligo-
trophic lake-trout lake this process would take a
very long time.

In the littoral zone, the width of the area of
clean rocks or sand is dependent directly on the
size of the lake and its exposure to the wind. In
the smaller New York lakes the lake trout general-
ly may be found spawning by windy points near
deep water (Royce 1936), on bottom kept clean
by the waves. A typical example of such shallow-
water spawning is to be found in Otsego Lake.

In larger lakes the lake trout may go to deeper
water for their spawning. Milner (1874) reports
that the lake trout in Lake Superior spawn in
7 feet to 15 fathoms of water. Evidence of
spawning in the deep water was provided by the
capture of ripe fish at that depth and by raising
in the nets fragments of honeycombed rocks
containing eggs. In Seneca Lake the lake trout
are captured for stripping in 100 to 200 feet of
water at a time when no lake trout are found in
shallow water. The fact that ripe lake trout
are captured over bottom that is suitable for
spawning is strong evidence that the trout
actually are spawning at these depths. Further
proof was provided by the capture on the spawning
bed in Seneca Lake, in April 1940, of a lake-trout
fry 25 millimeters in total length, in water 130
feet deep.

There is much evidence that these deeper
spawning areas are swept by strong currents.
The hatchery fishermen reported that their nets
were often rolled over and over by the currents
in Seneca Lake. In this same lake off Peach
Orchard Point the 40° F. isotherm rose from a
depth of 260 feet on September 29, 1941, to 100
feet on October 1 after a strong south wind;
on October 7 it was back down to a depth of 230
feet. Such a change must be accompanied by
the movement of a huge quantity of water.

These currents in Seneca Lake and the other
Finger Lakes have left evidence of a prevailing
direction of flow. All these lakes are very long
and narrow and lie with their long axes in very
nearly a north-south direction. Seneca Lake is
the largest, being about 40 miles long and 3 miles
wide at its widest point. The prevailing winds
come from the northwest or the southeast, blow-
ing obliquely to the south on the eastern shore
and obliquely to the north on the western shore
of the lake. The general result has been to form
the tips of deltas to the south of the stream mouths
on the eastern shore of the lake and to the north
of the stream mouths on the western shore.

In addition to the characteristic orientation of
the deltas, there is a definite gradation in the size
of the material deposited in the various parts of
the delta. Off the tip of Peach Orchard Point in
Seneca Lake down to a depth of at least 300 feet,
only clean gravel and rubble could be found with
a clamshell dredge, or seen in bottom photo-

LAKE TROUT BREEDING HABITS

67

A

1

>

9

i

n

§>'

{^

f

m

1 ^

Figi;r?; 3. — The bottom of Seneca Lake west-southwest off the tip of Peach Orchard Point where the lake trout congregate
during the spawning season. The picture covers an area on the bottom about 18 by 24 inches at a depth of 120
feet.

68

FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE

graphs* (fig. 3). The hghter materials, such as
mud, were deposited in the coves adjacent to
Peach Orchard Point.

Evidently other deltas in this lake have similar
deposits, since lake trout are captured in large
numbers during the spawning season near the
tips of the points.

The writer has found no evidence that lake
trout select a lake bottom supplied with spring
water for the deposition of their eggs. The
spawning area in Otsego Lake was on a fill about
100 feet out from the original shoreline which was
bedrock and showed no evidence of any spring
seepage. Comparison of numerous water tem-
peratures taken on the spawning area and in the
nearby lake at all seasons of the year showed no
difference in temperature. Additional evidence
was the presence of as thick an ice cover over the

' Ewing. Vine, and Worzel (1946) describe submarine photographic equip-
ment and techniques in detail.

spawning area on March 31 as on other parts of
the lake, just before the spring breakup, when any
springs should have caused some erosion of the
ice. No mention of spring water on lake-trout
spawning areas has been found in the literature
I have reviewed. It is concluded that for lake
trout, unlike some other species of trout, spring
water is a negligible factor in selection of a
spawning area.

SPAWNING ACT

All my observations on the spawning act of
lake trout reported here were made at a spawn-
ing area on Otsego Lake, N. Y. Otsego Lake is
about 8 miles long and averages three-fourths of
a mile in width. Its maximum depth is 168 feet,
and about 90 percent of the lake is more than 60
feet deep (Odell and Sennmg 1936). Chemical
conditions are ideal for lake trout, and the lake
has produced fairly good lake-trout fishing for

Figure 4.— The courtship act. The male at the left is nudging the female in the side.

LAKE TROUT BREEDING HABITS

69

many years. The spawning area kept under ob-
servation — the only one well known to the local
residents and the only one that could be found —
was along the middle of the west shore opposite
the deepest part of the lake.

Observations were made in this area on Novem-
ber 16 and 30 and on December 1 and 5, 1940,
and on December 1, 2, and 3, 1941. The trout
were observed from 7 a. m. to 11 p. m. on some
of those days, but the area was visited mostly in
the evening.

Some trout were on the spawning area at all
times of day during the spawning season, but most
of the activity was restricted to the evening hours.
During periods of bright sunlight only a few males
could be seen and they kept to fairly deep water
so that observation was difficult. The direct
rays of the sun were cut off by a mountain about
4 p. m. and then many trout, both males and
females, would arrive on the spawning area, and
the males would start courtship and attempt the
spawTaing act. The peak of the activity was

from 5 p. m. to 9 p. m. Later in the evening the
trout again disappeared until only a few were
left at 1 1 p. m., when observations were discon-
tinued.

No nest or redd was built. The males spent
their time cruising along close to the bottom,
occasionally giving the stones a little fillip with
their tails, and several showed considerable abra-
sion on the lower jaw and under side of the tail
from this fanning and digging. This activity
cleaned several hundred square feet of bottom so
thoroughly that it was easy to distinguish the
area on which the trout were working even when
they were not present.

It has been the experience of employees of the
New York State Conservation Department in
netting lake trout for spawn that the males appear
in the nets on the spawning area earher in the
season than the females, and usually more males
are caught. From this experience, and from the
fact that the males predominated on the area in
Otsego Lake, it seems probable that the males

Figure 5. — Just after completion of the spawning act. Two males have spawned with the female in the center.

70

FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE

are almost entirely responsible for any cleaning of
the spawning area before spawning.

Belying their appearance, the males are not
pugnacious. Occasionally one would make threat-
ening motions at another male, but no vigorous
fighting was observed. Several whitefish (Core-
gonus dupeaformis) and a large eel (Anguilla
hostoniensis) were seen among the milling lake trout
and were unmolested. It was noted, however,
that the males were nearly of the same size. Per-
haps they had already disposed of any venture-
some small males.

Merriman (1935) and others have observed the
spawning lake trout splashing at the surface. In
Otsego Lake this was noted only infrequently,
possibly because the spawning was on a steep
slope in 2 to 15 feet of water — deeper water than
that in which Merriman made his observations.

The males began their courtship upon the ap-
pearance of the females on the spawning area.
Usually the male nudged the female in the side
with his snout (fig. 4) and then attempted the
spawning act. Frequently two or more males
courted and attempted to spawn with a female at
the same time. During courtship the males dis-
played the characteristic coloration (fig. 1) and
commonly held the dorsal fin erect. These dis-
plays were apparently identical to those noted by
Merriman (1935).

The spawning act or attempts at it normally
consisted of one or two males approaching a
female, pressing against her sides with their vents
in close proximity and then quivering all over
(fig. 5). Usually the mouths of both sexes were
open and the dorsal fin of the male was held erect.
This act was seen clearly at close range several
times when no eggs or milt were expressed. On
two occasions a cloudiness was noted in the vi-
cinity of the vents which probably was caused by
the emission of sperm. No eggs were seen but
this could have been because of the distance of the
observer from the fish and the turbidity of the
water. No other act or behavior was seen which
could be construed to accompany oviposition.
Probably the attempt at the spawning act is a
part of courtship and is repeated over and over
again until fulfillment.

The spawning act was not limited to two or
three trout; as many as seven males tad three
females were seen at one time, all pressing to-
gether in one large group and quivering in unison.

No spawning act lasted for more than a few sec-
onds, and it seems that a female must accomplish
many unions to empty the ovaries completely.
The trout are not monogamous and it was impos-
sible to follow the movement of any one pair in
the milling group.

No tendency toward oviposition in any definite
place on the spawning area was observed. The
trout mated at random over the area cleaned off,
and there was no attempt by either sex to bury
the eggs. This seeming carelessness in regard to
the fate of their young was justified when one
attempted to find the eggs. A casual examination
of the bottom revealed practically no eggs, but
they could be picked up by the hundreds when
the stones were turned over carefully. Eggs were
recovered in water from 3 inches to 14 feet in
depth. Those collected in more than 2 feet of
water had to be taken in a Petersen dredge and
no estimate of their abundance could be obtained.
Along shore in less than 2 feet of water, however,
where only an occasional trout was seen spawning,
from 20 to 50 eggs could be recovered per square
foot of bottom. The eggs were difficult to pick
up, and the slightest motion of the water sent
them rolling further into crevices between the
rocks. In their selection of the bottom on which
to spawn, the lake trout had chosen an ideal
shelter for their eggs and young.

ENVIRONMENT AND DEVELOPMENT OF
EGGS AND LARVAE

EFFICIENCY OF FERTILIZATION

It has been a long-cherished belief of fish
culturists that the natural spawning of trout is a
highly inefficient, hit-or-miss process. Critical
investigations have shown this belief to be untrue.
White (1930) was able to hatch 79 percent of a
sample of naturally fertilized brook-trout eggs
removed from their redd and placed in a hatchery,
and 66 percent of another lot placed in a screen
basket and reburied in the redd. Hobbs (1937),
after intensively investigating the redds of brown
trout, rainbow trout, and quinnat salmon, found
that more than 99 percent of the eggs were
fertilized. He also found that subsequent heavy
loss in the pre-eyed, eyed, and alevin stages was
a result of adverse environmental conditions.
Under favorable conditions the natural reproduc-
tion was a highly efficient process.

LAKE TROUT BREEDING HABITS

71

A check of the natural spawning of lake trout
in Otsego Lake provided further evidence that
natural reproduction is efficient. On December 28,
1941, about 25 days after the trout were observed
on the spawning area, a sample of 309 eggs was
collected from under the rocks along shore with
a small rubber bulb and tube. Of these 309 eggs,
18, or 5.8 percent, were not fertihzed, and 47,
or 15.2 percent, had died. Seventy-nine percent
of the eggs were ahve and apparently entirely
normal after having been on the lake bottom nearly
a month. This probably represents a near mini-
mum figure for the survival (exclusive of those
eaten by predators) inasmuch as the eggs were of
necessity collected in only a few inches of water
where they were subject to heavy wave action.
The vast majority of the eggs were laid in deeper
water out of reach of available collecting appara-
tus and where they should have been better
protected.

TEMPERATURE REQUIREMENTS

Lake-trout eggs appear both to require and to
withstand slightly lower temperatures than the
eggs of other trout. Embody (1934) found that
brook- and rainbow-trout eggs suffered excessive
mortaUty and developed at a different rate when
the water temperature was below 37.4° F.' He
found, also, that lake- and brown-trout eggs
followed the same rate of development down to
35.2° F., and he judged that development pro-
ceeded normally. Brook trout usually spawn in
spring water so that their eggs are not subjected
to near-freezing temperatures during the winter
(Greeley 1932, Hazzard 1932, White 1930). Rain-
bow trout normally spawn in the spring when the
water is warming (Rayner 1941). Cook (1929)
reports that lake-trout eggs develop satisfactorily
at the Duluth, Minn., hatchery where water
temperatures remain about 32.5° F. throughout
the winter. The 140-day incubation period of
lake-trout eggs in Otsego Lake indicates an
average temperature of 36° or 37° F. in the egg-
development tables of Embody (1934). At the
Rome, N. Y., State hatchery high mortality
occurred in lake-trout eggs developing at water
temperatures above 50° F. when other trout eggs
developed normally. In other hatcheries, lake-
trout eggs from the same source developed nor-

* Rainbow-trout cpgs suiterod hiph mortality at temp(?raturcs below 43° F.,
but Emtwdy thought that in some cases this was due to inferior eRjts.

mally at lower temperatures. These facts would
indicate that lake-trout eggs can develop success-
fully in a lake in the winter, so long as they do not
freeze, and that they do not require spring water.
No data arc available on the temperature
requirements of the alevins. In the spring of
1941 they left the spawning area in Otsego Lake
when the water temperature was about 55° F.
It seems likely, therefore, that they avoid tem-
peratures above 60° F.

EFFECTS OF PREDATION

The data on the survival of eggs in Otsego
Lake do not indicate the true value because
they do not consider the removal of eggs by
predators. Predators are an ever present danger
to lake trout from the egg stage almost to maturity,
and cause a loss which is exceedingly difficult
to evaluate. No precise measurements have
ever been made on the effects of predation at any
stage in the growth of wild trout.

Many are the potential predators of eggs and
alevins. Table 6 lists the animals captured
within 100 yards of the lake-trout spawning area
in Otsego Lake during April and May 1941.
Many of these would destroy eggs if eggs were
availabe to them. Atkinson (1931) and Greene,
Hunter, and Senning (1932) found that numbers
of lake-trout eggs were eaten by suckers {Cat-
ostomus commersonii) and bullheads {Ameiurus
nebulosus). Both of these species occur in Otsego
Lake although they were not captured in the
immediate vicinity of the lake-trout spawning
area. Greeley (1936) states that a fisherman
reported finding lake-trout eggs in the stomachs
of Otsego Lake whitefish. Rayner (1941) found
many lake-trout eggs in the stomachs of adult
lake trout. A female taken by the writer on the
Otsego Lake spawning area had 13 lake-trout
eggs in its stomach. Small lake trout may be
even more voracious predators. W. C. Senning,
in a letter to me, reported finding lake-trout eggs in
every one of 31 small lake trout taken on the
spawning grounds in Seneca Lake in the fall of
1942. These lake trout ranged from 6K to 13
inches in length, and one 12-inch individual
had eaten 147 eggs. White (1930) found large
numbers of brook-trout eggs in brook-trout stom-
achs. Metzelaar (1929) reported that rainbow
trout ate numbers of their own eggs. Greeley
(1932) found brooks, browns, and rainbows to

72

FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE

Table 6. — Animals found on and near lake-trout spawning
area in Otsego Lake, Apr. 27-June 2, 1941

Phylum and
order

Coelenterata

Platyhelminthes.
Arthropoda;

Amphipoda.

Neuroptera...

Ephemerida. ,

Do-

Do

Do

Do

Odonata

Do

Do

Do

Do

Do

Do

Plecoptera

Coleoptera . . .

Trichoptera- .

Do

Do

Do

Diptera

Do

MoUusca:

Gastropoda...
Do-

Pelecypoda..
Chordata:

Pisces

Do

Do

Do

Do-

Do

Do

Do

Do

Do

Do

Do.

Do

Amphibia...

Species

Hydra sp

Planaria sp-

Hyalella sp

Sialis sp -

BlastuTUi sp -.

Ephemerella sp

Stenonema sp

Hexagenia sp

Ephemera sp

Qomphus sp -

Didymops transversa

Epicordulia princeps

Helocordulia tihleri. .

Neurocordulia obsoleta^ ..

Argia moesta

Enallagma sp

Neoperla sp

Dineutes sp

Stenophylaz scabripennis .

Molanna sp

Phryganea sp

Qtossosomatinae '

Chironomus sp

Tanytarsus sp

Limnea sp

Planorbis sp

Unidentifiable.

Coregonus dupeaforrrtis ^ .
Cristivomer n. namaycush.

Notropis h. hudsonius

Hyborhynchus notaius

Esoi niger

Angidlla hostoniensis

Perca fjavescens

Stizosledion v. vitreum

Bolesoma nigrum olmstedi
Micropterus d. dolomieu..

Lepomis gibhosus

AmhloplUes rupestris.

Cottus cognatas

Triturus viridescens.,.

Common name

Alderfly..
Mayflay.
....do---

do--.

do...

.do-

Dragonfly

do

do

. -do

do

Damsel fly

do..

Stone fly

Whirligig-beetle.

Caddisfly

do

do

do

Midge..

do..

Pond snail . .
Wheel snail.
Clam

Whiteflsh

Lake trout

Spot-tail shiner

Blunt-nosed min-
now.

Chain pickerel

American eel

Yellow perch

Yellow pike-perch.

Johnny darter

Small-mouthed

bass.
Pumpkinseed (sun-
flsh).

Rock bass

Slimy muddler

Newt -.-

Stage

Larva.
Nymph.

Do.

Do.

Do.

Do.

Do.

Do.

Do.

Do.

Do.

Do.

Do.

Do.

Larva.
Do.
Do.
Do.
Do.
Do.

' Two or more species.

be trout-egg eaters. On the Otsego Lake spawn-
ing area, an eel (Anguilla bostoniensis) and several
whitefish (Coregonus clupeajormis) were seen
industriously feeding among the stones where
the lake trout were spawning. In addition, a
slimy muddler {Coitus cognatus), which is known
to eat trout eggs, was captured in the immediate
vicinity.

What is the effect of this predation? Greeley
(1932) concluded that practically all the eggs of
rainbow, brown, and brook trout eaten were
waste eggs not buried in the redd, and that the
effect of egg predators on reproduction was neg-
ligible. Hobbs (1937) thought that the number
of eggs eaten from the redds of rainbow and
brown trout and quinnat salmon was very small.
The spawning trout themselves are important
predators but they could scarcely be accused of
eating all their own spawn.

It seems likely that predation would have no

more effect on the eggs of lake trout than it has
on those of other trout. If the lake trout can
spawn on the type of bottom they seem to prefer,
the eggs and alevins are certainly well protected
until they emerge from the rubble. It was neces-
sary to dig deep into the rubble in the Otsego
Lake spawning area to capture either eggs or
alevins.

Additional evidence is provided by the lack of
any lake-trout alevins in the stomachs of the
following fish captured in the immediate vicinity
of the lake-trout spawning area between April
27 and June 2, 1941:

6 whitefish {Coregonus clupeaformis)

I adult lake trout {Salvelinus { = Cristivomer] namay-
cush)

II shiners {Notropis hudsonius)

1 blunt-nosed minnow {Hyborhynchus notatus)

1 chain pickerel {Esox niger)

17 yellow perch {Perca flavescens)

22 johnny darters {Boleosoma nigrum olmstedi)

I smallmouth bass {Micropterus d. dolomieu)
4 common sunfish {Lepomis gibhosus)

13 rock bass (Ambloplites rupestris)

II slimy muddlers {Cottus cognatus)

These fish were all captured during the pre-
sumably vulnerable time the alevins were absorb-
ing the yolk sac and leaving the spawning bed.
Such negative evidence is inconclusive but reassur-
ing.

It is important to note that most trout-egg
predators have been indicted for their activities
during the time the eggs were being laid and not
after the eggs were hidden in the gravel. It is
concluded that lake-trout eggs and alevins suffer
little from predation after the spawning season,
and that during spawning the eggs that are eaten
are only those left exposed on the bottom.

DEVELOPMENT OF EGGS AND ALEVINS

Greeley (1936) collected eyed eggs and newly
hatched alevins on the Otsego Lake spawning
area on April 12, and more-advanced alevins on
May 9. I took newly eyed eggs on February 17,
1941, and later-eyed stages on March 31, 1941, by
chopping holes through the ice. (The lake trout
had been observed spawning December 5, 1940.)
Later, on April 27, with the surface water tempera-
ture 44° F., newly hatched sac fry were taken, and
on May 17, 1941, many more-advanced fry were
taken (temperature data in fig. 6). All the stages
were taken from the rubble on the spawning area.

LAKE TROUT BREEDING HABITS

73

30 40

TEMPERATURE

50 60 70

IN DEGREES FAHRENHEIT

Figure 6. — Temperature stratification of Otsego Lake
associated with different stages of larval development of
lake trout.

(Several hauls of the trawl in the vicinity of the
spawning area on April 27 and May 17 produced
no fry.) Both eggs and fry were well buried in the
stones. The eggs were taken with a Petersen
dredge, and only after the surface stones were
removed could they be found. The fry were all
taken with a trawl fitted with a heavy weight in
front which turned over the stones. On June 2,
1941, 18 tows of the trawl over the spawning area
and in the vicinity down to depth of 60 feet failed
to produce any young lake trout. They had
definitely moved from the spawning area and the
habitat of the earhest feeding stages was still
unknown.

Comparison of the development of wild fry
which were captured and of those grown in a hatch-
ery indicates that the time of hatching in Otsego
Lake in 1941 was about April 15, and the fry
left the shelter of the spawning area May 20 to 25.

In Seneca Lake, where the lake trout spawn
during late September and October, a single ad-
vanced fry was captured in about 130 feet of water
off Peach Orchard Point on April 2, 1940. This
fry was considerably more advanced than a

hatchery fry 2 months old. This would place
the time of hatching in late January and indicate
an incubation period of approximately 4 months.
Consideration of the type of bottom and the
kinds of invertebrate inhabitants (table 6) of the
lake-trout spawning area in Otsego Lake empha-
sizes the striking resemblance of this area to a
typical trout-stream environment. Clean gravel
and rubble bottom inhabited by stonefly and may-
fly nymphs and caddis larvae ordinarily would be
associated with a stream instead of a lake. Cer-
tainly it seems that lake-trout fry and fingerlings
would fare best under conditions similar to those
selected by the young of other trout.

This trout-stream-like environment in Otsego
Lake gave me high hopes of capturing the early
fingerling stages in the vicinity. But all efforts,
including those with minnow traps, trawl, and
shore seine, were unsuccessful. No helpful clues
were found in the literature, for lake-trout finger-
lings have been reported only from shoal water
and small tributaries. Kendall and Goldsborough
(1908) captured several lake trout, 1.87 to 2.37
inches long, in small spring tributaries of First
Connecticut Lake on July 16 and 18 and August
10. Neave and Bajkov (1929) reported taking
10 lake trout, 32 to 45 mm. long, with a hand net
in a small inlet creek at Pyramid Lake, Nev.
Miller and Kennedy (1948) noted that fry, and
1-, 2-, and 3-year-old lake trout were found in
shallow water along a bouldery shoreline of Great
Bear Lake, Mackenzie, Canada. Lake-trout fin-
gerlings are not found in such habitats in the
summer in New York. The biological survey of
the New York State Conservation Department
captured none in extensive seining of the shores
of the Adirondack lakes and streams, many of
which were adjacent to lake-trout waters. There
seems to be little doubt that in New York they live
in the deeper waters of the lakes in the summer
and probably seek rocky bottom.

JUVENILE LAKE TROUT OF KEUKA LAKE

Intermittently from April 18 to September 16,
1940, effort was made to capture fingerling and
juvenile stages of lake trout in Keuka Lake.
Their capture was attempted with gill nets, trawls,
set lines, and minnow traps. A number of 100-
foot sections of gill nets of %-inch to 1 J^inch bars
were set for an aggregate of 67 nights at depths of

74

FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE

10 to 130 feet. Fifty -nine tows of a trawl were
made over a similar range of depths. A set line
equipped with 80 No. 7 hooks was set for 4 days
covering depths from 15 to 40 feet. Minnow
traps were set for 8 days at depths from 40 to 80
feet.

Included in the catch were 41 lake trout (all
caught in gill nets) of which 13 were more than
15 inches in total length — the minimum legal size
in New York. The stomach content of the 13
legal-sized trout, and of 1 1 others of legal size
gathered from anglers, was 100 percent alewives
{Pomolobus psevdoharengus) or unidentifiable fish,
probably of the same species (anglers report
finding practically nothing but alewives in lake-
trout stomachs).

The lengths and stomach contents of the sublegal
specimens are listed in table 7. Of the 16 speci-
mens between 10 and 15 inches in length, only one
had eaten arthropods, while the principal food of
those between 6 and 10 inches was arthropods,
mostly Mysis relicta.

Table 7.

-Food of lake trout less than 15 inches long from
Keuka Lake, 1940

Total
length

(inches)

Date of
capture

Stomach contents

im.....

May 11

do

Empty.

Unidentifiable fish remains.

14

do

3 Pomolohus pseudobarengus' 2 unidentifiable fish

13ii

.. do

2 Pomolohus pseudoharengu3.

13

...do

12^

do

12)^.....

12H

llH---

n'A

IIM

June 29

May 11

June 29

May 24

.do

Do.
Do.
Do.
Do.
Do.

lOJ^

lOJi

May 11..

do

Do.
Empty.

lO^j ....

.. do

W'/s

lOJi

9H

9H

1;;::;;

Sept. 11

May 25

Sept. 13-16 ...

May 24

Sept. 13-16...

do

do

do

1 mayfly nymph (Ephemerinae); 1 unidentifiable
fish.

5 Pomolohus paeudokarengus.

1 Pungitius pungitius; 23 Mysis Telicta.

Unidentifiable fish remains.

1 Pungitius pungitius: 1 unidentifiable fish.

1 Cottus cognatus; 9 Afysis relicta.

12 Mysis Telicta.

7H-.---!

do

do

34 Mysis relicta.

6H

do

10 Mysis Telicta.

6'4

do . ..

do

6ii

do.

28 Mysis relicta.

Summary: Of lake trout 10 to 15 inches in total length, 14 stomachs con-
tained fish remains and 1 stomach contained arthropod remains. Of lake
trout 6 to 10 inches in total length, 4 stomachs contained fish remains and 10
stomachs contained arthropod remains.

In most cases capture of the lake trout was
very erratic. The 10 small specimens taken May
1 1 were found in the same place at very nearly the
same depth of 100 feet. Nets set there on follow-
ing nights caught nothing. The other small

specimens taken during May and June and all the
larger lake trout were caught, one or two at a time,
in different places but almost entirely at depths
of 80 to 120 feet.

Some consistency was found, however, in the
capture of the young lake trout caught September
11 to 16, 1940. These were taken, two or three
a rtight, in %- to K-inch bar gill nets set in one
restricted location off the southern tip of Bluff
Point, a very rocky, steep underwater slope,
between depths of 40 and 70 feet. Nets of the
same mesh set at the same depths in the vicinity
on mLxed mud and rubble bottom failed to catch
any trout. As large lake trout were taken in
larger-mesh nets in the same area, it seems that the
juveniles must have been relying on the shelter
of the rocks for protection from their voracious
elders.

Scale examination indicated that these 6}i- to 10-
inch trout were yearlings and 2-year-olds. Since
the lake trout of Keuka Lake spawn in late
November and probably hatch in late April
(see p. 64, table 5), a rate of growth comparable
to hatchery growth would allow them to reach
only 2 or 3 inches by the first September. Possibly
these fingerling fish could be found in the same
location as the yearlings were found. Lack
of time and equipment prevented any further
effort in this direction but it is a good stage at
which to resume the search in the future.

SUMMARY

Lake trout were observed during their spawning
season in 1939, 1940, and 1941 in several lakes in
New York State, and actual spawning was seen
in Otsego Lake, N. Y. Extensive data on spawn-
taking operations were obtained from the New
York State Conservation Department, and exist-
ing literature on the subject was reviewed.

It was found that, except for a striking color
change in the males while on the spawning area,
lake trout lack sexual dimorphism. They mature
in about their sixth year at lengths varying from
15 to 30 inches in the different lakes.

Spawning occurs once each year, during the
autumn. The date varies from late September
to early December depending on the race of trout,
the amount of sunlight, the autumnal drop in
temperature, and the depth of the lake.

In the deep water of Seneca Lake, one race

LAKE TROUT BREEDING HABITS

75

spawned early. In all other lakes studied, the
lake trout spawned in shallow water and usually
later. Increased cloudiness in July, August, and
September, and low temperatures in September,
advanced the date of spawning in Raquctte
Lake. Shallower lakes had earlier spawning
dates. At the time of spawning, water tempera-
ture varied from 58° to 37° F., but in Raquette
and Otsego Lakes it was observed that spawning
times approximated the turn-over times of the
lakes. Generally, the spawning period was about
20 days, but it varied from 10 to 40 days and was
fairly consistent from year to year in any one lake.

Spawning, whether in shallow or deep water,
took place on gravel or rubble bottom that had
crevices into which the eggs could roll. No nest
or redd was built. No evidence of spring water
was observed near any spawning area.

In the spawning act, which usually occurred
during the evening, from 2 to 10 lake trout par-
ticipated. Each attempt at spawning lasted
only a few seconds; the act was repeated many
times.

Approximately 1 month after spawning, a
sample of eggs recovered from the crevices in the
rocks of Otsego Lake was found to be 79 percent
alive. No measurement of the effects of preda-
tion on eggs was possible, but it was estimated
that only eggs that failed to roll into crevices
between the stones could be eaten by predators.

In Otsego Lake in 1941 the eggs hatched about
April 15 and the fry left the spawning area about
May 22. In the deep water of Seneca Lake
where the lake trout had spawTied in early October
a single advanced fry was taken April 2, 1940.
Its development indicated that hatching occurred
in late January.

Extensive operation of a small beam trawl, set
hnes, and minnow traps in Otsego, Keuka, and
Seneca Lakes failed to produce any lake trout
between advanced fry stage and a length of about
6 inches. Twelve specimens between 6 and 10
inches long that were captured in gill nets in Keuka
Lake were found to be 1- and 2-year-olds and to be
feeding mostly on Mysis relicta.

ACKNOWLEDGM ENTS

Deep appreciation is expressed to the following
people whose assistance made this work possible:
Dr. A. H. Wright, professor of zoology, Cornell

University, Ithaca, N. Y., gave much encourage-
ment and made funds available; Peter I. Tack,
A. H. Underbill, and William M. La%vrence,
graduate students, and Philhp Strong, fish hatch-
ery foreman, provided a large amount of help in
the netting operations and the aquatic photog-
raphy.

Members of the New York State Conservation
Department were most cooperative and generous
with their time and equipment. Among those to
whom I am particularly indebted are S. M.
Cowden, supervisor of fish culture; A. P. Miller,
district supervisor of fish culture; Dr. Emmehne
Moore and Dr. W. C. Senning, aquatic biologists;
Charles Deuell, David Haskell, K. B. Nichols,
and L. D. Winslow, fish hatchery foremen; and
L. D. Tompkins, game protector.

I am further indebted to V. S. L. Pate and
Minter J. Westfall, Jr., for identification of aquatic
insects from Otsego Lake, and to J. R. Westman,
for scale samples and data on the lake trout of
Lake Simcoe, Ontario.

LITERATURE CITED

Atkinson, N. J.

1931. The destruction of grey trout eggs by suckers and
bullheads. Trans. Amer. Fisheries Soc, vol. 61, pp.
183-188.
BissoNETTE, T. H., and J. Wendell Burger.

1940. Experimental modification of the sexual cycle of
fish. Abstracts of papers presented at the North-
eastern Fish Culturists' Meeting, p. 12.
Cook, W. A.

1929. A brief summary of the work of the Bureau of
Fisheries in the Lake Superior region. Trans. Amer.
Fisheries Soc, vol. 59, pp. 56-62.
Dymond, John Rich.\rd80N.

1926. The fishes of Lake Nipigon. University of
Toronto Studies, Publications Ontario Fisheries Re-
.search Laboratory, No. 27, pp. 3-108.
Embody, George C.

1934. Relation of temperature to the incubation periods
of eggs of four species of trout. Trans. Amer. Fish-
eries Soc, vol. 64, pp. 281-292.
EwiNG, Mavrice, a. Vine, and J. L. Worzel.

1946. Photography of the ocean bottom. Jour. Optical
Soc. America, vol. 36, No. 6, June 1946, pp. 307-321.
Fry, F. E. J.

1939. A comparative study of lake trout fisheries in
Algonquin Park, Ontario. Univ. of Toronto Studies,
Biol. Ser., No. 46: Publications of the Ontario Fish-
eries Research Laboratory, No. 58, pp. 7-69.
Fry, F. E. J., and W. A. Kennedy.

1937. Report on the 1936 lake trout investigation,
Lake Opeongo, Ontario. Univ. of Toronto Studies,

76

FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE

Biol. Ser., No. 42: Publications of the Ontario Fish-
eries Research Laboratory, No. 54, pp. 3-20.
Greeley, John R.

1932. The spawning habits of brook, brown, and rain-
bow trout, and the problem of egg predators. Trans.
Amer. Fisheries Soc, vol. 62, pp. 239-248.

1936. A Biological Survey of the Delaware and Susque-
hanna Watersheds. II. Fishes of the area with an-
notated list. Supplemental to 25th Ann. Rept., New
York Conserv. Dept., 1935, pp. 45-88.

Green, C. W., R. P. Hunter, and W. C. Senning.
1932. A Biological Survey of Oswegatchie and Black
River systems. Spjtwn-eating by suckers and bull-
heads. Supplemental to 21st Ann. Rept., New
York Conserv. Dept., 1931, pp. 26-28.

Hazzard, a. S.

1932. Some phases of the life history of the eastern
brook trout Salvelinus fontinalis (Mitchell). Trans.
Amer. Fisheries Soc, vol. 62, pp. 344-350.

HoBBS, Derisley F.

1937. Natural reproduction of the Quinnat salmon,
brown and rainbow trout in certain New Zealand
waters. New Zealand Marine Dept., Fisheries Bull.,
No. 6, pp. 7-104.

Hoover, Earle E., and Harry E. Hubbard.

1937. Modification of the sexual cycle in trout by the
control of light. Copeia, No. 4, pp. 206-210.
HuBBS, Carl L.

1930. Further additions and corrections to the list of
the fishes of the Great Lakes and tributary waters.
Papers of the Michigan Acad. Science, Arts and
Letters, vol. XI, pp. 425-436.
Kendall, William Converse, and E. L. Goldsborough.
1908. The fishes of the Connecticut Lakes and neighbor-
ing waters. U. S. Bur. Fisheries Doc. No. 633,
77 pp., 10 pis., 5 figs.
McCay, C. M., L. a. Maynard, J. W. Titcomb, and
M. F. Crowell.
1930. Influence of water temperature upon growth and
reproduction of brook trout. Ecology, vol. XI, pp.
30-34.
Merriman, Daniel.

1935. Squam Lake trout. Bull. Boston Soc. Nat.
Hist., No. 75, pp. 3-10.
Merriman, Daniel, and H. P. Schedl.

1941. The effects of light and temperature on game-
togenesis in the four-spined stickleback, Apeltes

quadracus (Mitchill). Jour. Exper. Zool., vol. 88,
No. 3, pp. 413-449.
Metzelaar, Jan.

1929. The food of the trout in Michigan. Trans.
Amer. Fisheries Soc, vol. 59, pp. 146-152.
Miller, R. B., and W. A. Kennedy.

1948. Observations on the lake trout of Great Bear
Lake. Jour. Fisheries Research Board of Canada,
vol. 7, No. 4, Feb. 1948, pp. 176-189.
Milker, James W.

1874. Report on the fisheries of the Great Lakes; the
result of inquiries prosecuted in 1871 and 1872.
U. S. Fish Comm. Rept. 1872-73, Part II, pp. 1-78.
Mottley, C. McC.

1936. The hooked snout in the Salmonidae. Prog.
Repts. Pacific Biol. Sta., Nanaimo, British Columbia,
and Pacific Fish. Exp. Sta., Prince Rupert, British
Columbia, No. 30, pp. 9-10.
Neave, F., and A. Bajkov.

1929. Reports of the Jasper Park lakes investigations,
1925-26. V. Food and growth of Jasper Park fishes.
Contrib. to Canadian Biol, and Fisheries, New Ser.,
vol. IV, No. 16, pp. 199-299.

Odell, T. T., and W. C. Senning.

1936. A biological survey of the Delaware and Susque-
hanna watersheds. III. Lakes and ponds of the
Delaware and Susquehanna watersheds. Supple-
mental to 25th Ann. Rept., New York Conserv.
Dept., pp. 89-121.
Rayner, H. J.

1941. The development of a management policy for the
rainbow trout of the Finger Lakes. Ph. D. Thesis,
Cornell Univ., June 1941.
Royce, James S.

1936. Collecting eggs from lake trout in New York
lakes. Fish Culture, 2 pp.

SURBER, ThADDEUS.

1933. Rearing lake trout to maturity. Trans. Amer.
Fisheries Soc, vol. 63, pp. 64-68.
Van Oosten, John.

1935. The value of questionnaires in commercial fisher-
ies regulations and surveys. Trans. Amer. Fisheries
Soc, vol. 64, pp. 107-117.
White, H. C.

1930. Some observations on the eastern brook trout
(S. fontinalis) of Prince Edward Island. Trans.
Amer. Fisheries Soc, vol. 60, pp. 101 108.

U S. GOVERNMENT PRINTING OFFICE

UNITED STATES DEPARTMENT OF THE INTERIOR, Oscar L. Chapman, Secretary
FISH AND WILDLIFE SERVICE, Albert M. Day, Director

DECLINE OF THE LAKE TROUT FISHERY

IN LAKE MICHIGAN

By Ralph Hile, Paul H. Eschmeyer, and George F. Lunger

FISHERY BULLETIN 60

From Fishery Bulletin of the Fish and Wildlife Service

VOLUME 52

UNITED STATES GOVERNMENT PRINTING OFFICE

WASHINGTON : 1951

For sale by the Superintendent of Documents, U. S. Government Printing Office, Washington 25, D. C.

Price 20 cents

CONTENTS

Page

Materials and methods 77

Production trends in Lake Michigan, 1879-1949 78

Production in State of Michigan waters, 1891-1908 and 1929^9 81

Abundance in State of Michigan waters, 1929-49 88

Fishmg intensity in State of Michigan waters, 1929^9 90

Relations of production, abundance, and fishing intensity 92

Summary 94

Literatm'e cited 95

II

DECLINE OF THE LAKE TROUT FISHERY IN LAKE MICHIGAN

By Ralph Hile and Paul H. Eschmeyer, Fishery Research Biologists, and George F. Lunger, Statistician

Collapse of the fishery for lake trout, Salveliniis
[=Cristivomer] namaycush, of Lake Huron has
been treated in detail in a recent publication by
Hile (1949). In the present paper we take up the
unpleasant task of describing the decline of the
lake-trout fishery in yet another of the Great
Lakes, Lake Michigan. Lake Superior now stands
as the only significant center of conunercial pro-
duction of that species yet remaining in the United
States.

In this, as in the earher paper mentioned, treat-
ment will be limited to a statistical account of the
changes that have taken place in the lake-trout
fisheiy. We offer no extended argument on the
role of the sea lamprey in this most recent debacle,
other than to express the considered opinion that
on the basis of ciu-rently available evidence this
parasite must be held the major cause of the
catastrophes that have overtaken both Lake
Huron and Lake Michigan.

MATERIALS AND METHODS

The statistics on the production of lake trout
in the individual States over the period 1879-
1940, incorporated in table 1, were adapted from
Gallagher and Van Oosten (1943) and are from
the sources listed in that publication. Our annual
totals, however, are in agreement with those of
Gallagher and Van Oosten only for those years in
which statistics were available for aU four States
bordering the lake. In a number of years statis-
tics were at hand for Michigan and Wisconsin but
not for lUmois and Indiana; in such situations
those authors recorded the yields from the first
two States as the totals for Lake Michigan. Our
totals in the same situations include estimates of
the Illinois-Indiana catch. On the basis of the
actual distribution of the take among the States
in the 8 years with complete data from 1885
through 1917 and in the 6 years ' from 1922

' For this purpose the 1925 data were usable since the Indiana-Illinois
catch was included in the total; statistics for the two States Individually,
however, were not available.

through 1929 we derived the correction factors
1.0291 and 1.0683. The former factor was ap-
plied to the combined Michigan-Wisconsin catch
to give an adjusted grand total in years lacking
lUinois-Indiana data through 1919; the latter
factor was used for years after 1919. To be sure,
the percentage contribution of Illinois and Indiana
varied within each of the two periods, but the
derivation of a greater munber of factors would
not have been profitable. We have not consid-
ered it advisable to estimate the Lake Michigan
total in any year for which we had data for only
one State.

Statistics on production after 1940 were com-
piled directly from commercial fishei-men's re-
ports in the Ann Arbor offices of the Fish and
Wildlife Service (Michigan) or supplied by State
conservation agencies (Wisconsin, Illinois, and
Indiana) .

The data on the yield of lake trout in the several
statistical districts of the State of Michigan waters
of Lake Michigan for 1891-1908 were tabulated in
the Service's Great Lakes offices from original
records supplied by the Michigan Department of
Conservation."

The detailed information on production, fishing
intensity, and estimated availability of lake trout
in the State of Michigan waters in 1929^9 is
based on analyses of monthly reports of com-
mercial fishermen licensed by the State of Michi-
gan. These reports, which were supplied by the
department of conservation, contain data on
fishing locality, kind and amount of gear fished,
and kinds and quantities of fish captured for each
day of fishing by each Ucensee.

The methods employed in estimating the
abundance of the principal species and the intens-
ity of the fishery in the State of Miciiigan waters
of the Great Lakes have been described in detail in
earlier publications (Hile 1937; Hile and Jobes

> The Works Progress Administration gave valuable assistance in this
vorlc

77

78

FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE

1941; Van Oosten, Hile, and Jobes 1946). The
boundaries of the eight statistical districts, M-1 to
M-8, are given in figure 2.

PRODUCTION TRENDS IN LAKE
MICHIGAN, 1879-1949

The trends of production of lake trout from 1879
through 1949 perhaps can be brought out best
through comments on the yield over certain
periods of years (tables 1 and 2; fig. 1).

The take in 1879, the fu'st year for which we have
a record, was comparatively low (2,659,000
pounds). Catches were higher in 1885 (6.431,000
pounds) and 1889 (5,580,000 pounds) but the take
in each of those years and the mean for the two
(6,006,000 pounds) were far below the level that
characterized the period beginning with 1890.
It may be assumed that the fishery was in the
process of development in 1879-89.

The interval 1890-1911 was one of rather con-
sistently high production. The take exceeded 8
million poimds in 7 of the 11 years for which lake
totals are recorded and was more than 9 million
pounds in 1 of these 7 (9,282,000 pounds in 1896).
Of the remaining 4 years, 2 had yields between 7
and 8 million pounds, 1 between 6 and 7 million,
and 1 less than 6 million. The two lowest catches
(6,624,000 poimds in 1892 and 5,286,000 pounds
in 1899) both deviated sharply from the general
level for the period and both can be attributed to
the low yields recorded for Wisconsin. The grand
average catch => for 1890-1911 was 8,230,000
pounds or 2,224,000 pounds greater than for 1885-
89. Every State but Indiana shared in the in-
crease; the rise was greatest, however, in Wiscon-
sin (1,950,000 pounds).

The production of lake trout in Lake Michigan
was at a decidedly lower level in 1912-26 when the
average yield of 7,007,000 pounds was 1,223,000
pounds below that of 1890-1911. Of the 14 years
for which there are totals (see footnote 1 to table 1
concerning the exclusion of data for Wisconsin in
1921) 5 had catches between 7 and 8 million
pounds, 8 between 6 and 7 million pounds, and 1
less than 6 million pounds. The highest yield was
7,928,000 pounds in 1915 and the lowest was
5,979,000 pounds in 1918. Dechnes from the
preceding period of 932,000 pounds in Wisconsin

> To obtain full use of the data of table 1, the means in the body of table 2
were determined from all records of yield for each State during the indicated
periods and these State means were added to obtain the totals at the right.

and 459,000 pounds in Michigan, were compen-
sated to a small degree by increases of 132,000
pounds in Indiana and 36,000 poimds in Illinois.

Table 1. — Production of lake trout in Lake Michigan,
1879-1949

[In thousands of pounds]

Year

State

Total

Michigan

Wisconsm

Illinois

Indiana

1879

2,659

1880

1881

1882

1883

1884

1885. - -

3,725

2,668

4

34

6,431

1886

1887

1888

1889

2,950
4,674

2,455
3.464

25
72

150
155

5,680

1890

8,364

1891

3,686
3,616
3,122
2 668

2'82i"
5,404
5, 865

1892

6,624

1893

8,774

1894

8,781

1895

2,392

5,304

7,920

1896

3,020
2,872

6,000
4,711

-J--

...

9,282

1897

7,823

1898

2,540
2,370
2,016
2,844

1899

2,804

77

35

6,286

1901

~

1902

4,337
4, 055

1903

4,613

199

76

8,943

4,254
4,456

1905 -

1906

6,103

1907

4,271

1908

4,023

4,328

150

130

8,631

1909

_»-

4,337

1911

3,526

4,640

8,404

3,003

3,558

6,752

IQia

2,544

3,761

6,488

1914

2,711

4,126

7,036

191=1

3 853

3 851

7,928

IQlfi

2,805

3,195

6,174

1917.

2,866

3,745

169

123

6,904

2 456

3, .354

5,979

2,735
3,143

3, 849
3,840

6,776

1920.

7,461

3,107
3,264

■8,642
3. 801

12,651

19?2

203

272

7,640

1923

2,767
3 472

3.419
3 752

6,599

1Q?4

7,717

1Q95

3,422

3. 101

J 6, 894

1926

3,352

2,762

165

250

6,530

1927

2,900

2, 379

167

2.53

6,699

1928..

1,831

2.629

172

187

4,819

1929

2,198

3,817

247

132

6,394

1930.. ..

2,556

2,316

383

186

5,441

1931...

2, 6.52

2,673

202

106

6,632

1932

2,746

2,345

281

98

6,470

1933... . .

2,379

2,481

262

90

6,212

1934

2,053

2,590

225

88

4,957

1935. -_

2, 451

2,042

260

120

4,873

1936

2,127

2,232

274

130

4, 763

1937

2,264

2,353

271

100

4,988

1938

2,480

1,940

311

174

4,906

1939 -

2,778

2,358

318

205

6,660

1940.

2,780
3,189

2,492
2.747

814
705

179
146

6,266

1941.

6,787

1942

2,641
2, 814

2.695
2,825

1,111
1,193

38
28

6,484

1943

6,860

1944 .

2,609
2,228

2,852
2,516

1,036
694

6,498

1945.

5,437

1946

1,908
914

1,650
1,178

416
333

1
1

3,974

1947 -

2,425

1948.

589

542

65

C)

1,197

1949.

223

116

4

342

1 The recorded yield of 8,642,000 pounds in Wisconsm in 1921 is so badly
out of line with data for neighboring years as to be held unreliable. It was
not plotted in fig. 1 or employed in the computation of any means or per-
centages.

2 No breakdown available of the 371,000 pounds taken in Indiana and Illi-
nois.

» Less than 500 pounds.

DECLINE OF LAKE TROUT IN LAKE MICHIGAN

79

1920

1945

Figure 1. — Production of lake trout in Lake Michigan, 1889-1949. Upper solid line = entire lake; broken line=

Wisconsin; lower solid line = Michigan.

The take of lake trout fluctuated about a still
lower level in 1927-39 when the average total for
the lake was 5,293,000 pounds, 1,714,000 pounds
below the mean for 1912-26 and 2,937,000 pounds
less than that for 1890-191 1. The catch exceeded
6 million pounds only once in 13 years (6,394,000
pounds in 1929 — again a sharp deviation of the
Wisconsin figure from the characteristic level was
responsible for the extreme) ; it was between 5 and
6 million pounds in 6 years, and less than 5 million
pounds in 6 years. The lowest catch of the period
was 4,763,000 pounds in 1936. Michigan, Wis-

consin, and Indiana contributed to the decline
from 1912-26 to 1927-39 with decreases of 616,000,
1,107,000, and 71,000 pounds, respectively. The
Illinois catch, on the contrary, was increased by
80,000 pounds in the latter period.

The lake-trout fishery of Lake Michigan enjoyed
a brief period of heightened productivity in 1940-
44 when the take exceeded 6 million pounds in
every one of the 5 years and averaged 6,578,000
pounds, or 1,285,000 pounds above the 1927-39
mean. To a considerable extent the improvement
can be attributed to the large increase of 713,000

80

FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE

Table 2. — Average production of lake trout in Lake Michigan, by periods
[In thousands of pounds]

Period

Number
of years '

Item

State

Michigan Wisconsin Illinois Indiana

Total

1879

1885-89..

1890-1911

1912-26

1927-39

1940-44

1946-49

Production-
Mean annual

Percentage
Mean annual

Percentage
Mean annual

Percentage
Mean annual

Percentage
Mean annual

Percentage
Mean annual

Percentage

production..

of total

production.

of total

production.

of total

production.

of total

production.

of total

production,
of total

3,338

55.6
3,492

42.4
3,033

43.3
2.417

45.7
2,807

42.7
1.172

43.8

2,562

42.7

!4.512

54.8

' 3, 580

61.1

' 2, 473

46.7

2, 722

41.4

1,200

44.9

14
2
143
1.8
179
2.6
269
4.9
972

14.7
302

11.3

92
1.5

83
1.0
215
3.1
144
2.7

78

1.2

2,659
6,n06

100
8,230

100
7,007

100
6,293

100
6,578

100
2,674

100

1 Number of years for which statistics were available in at least 1 State or
for the entire lake.

2 The reported Wisconsin production for the years 1892 and 1899 was far
below the level characteristic of the period. If these years are excluded, the
Wisconsin mean becomes 4,822 and the percentages and total change
accordingly.

pounds in Illinois, a rise exceeding the combined
increases in Michigan (390,000 pounds) and Wis-
consin (249,000 pounds). Indiana alone experi-
enced a decline (66,000 pounds).

The sharp drop in the recorded Indiana take to
a lower level during the 1940-44 interval probably
reflects improvement in the collection of statistics
more than a decrease in output. Indiana pro-
ducers, who traditionaUy take the bulk of their
catch of lake trout in State of Michigan waters,
have to our best knowledge customarily reported
their entire production to both Indiana and Mich-
igan. There is considerable evidence, therefore,
that part of the take of Indiana fishermen in
earlier years was reported in duplicate. In view
of the relatively small production of these opera-
tors, the efl^ects on the statistics for the entire lake
were not particularly damaging, but the figures for
Indiana before about 1942 must be viewed with
some skepticism.

The period 1940-44 is exceptional for its brevity.
Statistics for the preceding three periods demon-
strated a tendency for the productivity of the lake-
trout fishery to fluctuate closely about a character-
istic level for from 13 to 22 years. In view of this
tendency, it might well be expected that the new
high level reached in 1940 would be maintained
longer than 5 years. That it was not maintained
suggests that some disruptive factor intervened.
The sea lamprey qualifies well as that factor.

Although the downward trend of production

' Excluding 1921 for which year the reliability of the Wisconsin data appears
questionable.

* The reported Wisconsin production for 1929 was considerably above the
level characteristic of the period. If this year is excluded, the_ Wisconsin
mean becomes 2,362 and the percentages and total change accordingly.

actually started a year earlier, 1945 can be set a
the beginning year of the recent disastrous decline.
In this year the catch dropped by more than a
million pounds and fell distinctly below the level
of 1940—44. Once the decline started, its progress
was spectacular. In 1946 the take was under 4
million pounds for the first time since 1879, and
each of the years 1947 to 1949 set a new record
low. It is the high rate of decrease rather than
the average of 2,674,000 pounds that makes the
1945-49 period significant.

The collapse of production in the lake-trout
fishery of Lake Michigan resembles closely that
described for Lake Huron by Hile (1949). Indeed,
the decline appears to have been even more rapid
in Lake Michigan than in the United States
waters of Lake Huron. This point can be brought
out by a comparison of the number of years
required for a 90-percent or gi-eater decline from
the last year with the take above the "modern"
average. In Lake Michigan this average can
be set at 5,651,000 pounds (the mean for 1927-44),
and the last year in which the take exceeded that
figure was 1944 (6,498,000 pounds); only 5 years
later the catch had dropped by 94.7 percent
(to 342,000 pounds m 1949). In the United
States waters of Lake Huron the "modern normal
yield" was set by Hile at 1,685,000 pounds (the
mean for 1895-1939), and the last year with an
output above this figure was 1935 (1,743,000
pounds); 10 years were required for the catch
to decline 90.1 percent (to 173,000 pounds in 1945).

DECLINE OF LAKE TROUT IN LAKE MICHIGAN

81

PRODUCTION IN STATE OF MICHIGAN
WATERS, 1891-1908 AND 1929-49

Records of the annual take of lake trout in the
several statistical districts * of the State of
Michigan in 1891-1 90S (table 3) make possible
the comparison of the actual productivity of
various regions and of their percentage contri-
butions to the total for the lake * in that period

Table 3. — Production of lake troul in Michigan statistical
districts, 1891-1908
[In thousands of pounds]

District

Year

Total

M-1

M-2

M-3

M-4

M-5

M-6

M-7

M-8

1891

171

349

1,554

130

346

228

395

513

3,686

1892

35

390

1.691

77

379

290

257

496

3,616

1893 - -

174

144

1,392

98

311

318

360

324

3,122

18M

142

249

1,285

86

255

224

185

243

2,668

1895

109

57

1,312

118

267

185

165

180

2,392

1896

119

392

1,529

151

307

207

160

155

3,020

1897

176

411

1,456

76

212

200

174

167

2,872

1S98

161

288

1,367

46

233

258

98

89

2, 540

1899

127
90

264
191

1,160
782

47
42

298
259

190
190

130
195

164
266

2,370

1900

2.016

IWl . .

168

361

1,073

78

330

344

212

279

2. 844

1902

307

470

1,704

112

362

345

542

493

4,337

1903

380

598

1,534

94

422

246

368

412

4, 055

1904 ,

363

572

1,708

138

428

311

296

438

4, 254

1905

382

538

1,903

158

443

380

238

412

4.456

1906 -

332

348

2, 325

195

498

503

446

456

5. KB

1907

299

298

1,670

170

437

446

503

448

4,271

1908

300

421

1,.553

134

33U

m

484

318

4,023

1891-1908

mean.

213

352

1,500

108

340

297

289

325

3,425

Percentage

of total-.-

6.2

10.3

43.8

3.2

9.9

8.V

8.4

9.5

100

Table 4. — Production of lake trout in Michigan statistical

districts, 1929-49

[In thousands of pounds]

Year

District

Total

Produc-
tion
indei i

M-1

M-2

M-3

M-4

M-5

M-6

M-7

M-8

1929

182
203
220
194
134
72
77
158
236
248
167
83
75
56
91

146

S.7

47
29
11
46
178
149

153
234
300
331
298
276
242
269
296
243
234
220
354
251
299

266

10 5

195
145
79
25
25
3

912
986

1,020
898
692
669
771
823
738
801

1,047
739
910
684
837

835

32.9

675
599
448
219
87
23

68
90
102
113
102
71
89
76
88
117
100
109
141
133
122

101

4.0

131
96
68
38
19
13

273
286
321
387
449
380
432
363
447
437
407
427
449
385
453

393

15.5

462
299
263
126
86
21

291
270
291
354
303
278
306
143
147
183
286
424
413
283
274

282

11.1

251

227

152

71

19

5

146
224
249
313
206
144
234
111
131
148
195
289
414
342
216

224

8.8

261
247
293
155
45
2

174
262
148
156
196
163
300
193
180
303
370
488
432
508
523

293

11.5

587
586
593
234
131
6

2,198
2,556
2,662
2.746
2,379
2,053
2.461
2.127
2,254
2,480
2,778
2,780
3.189
2,641
2,814

2,540

100

2,609

2,228

1,908

914

589

223

86

19.30

101

1931

104

1932

108

1933

94

1934. _..

81

1935

96

1936

84

1937- -

89

1938-

98

1939

109

1940

109

1941

126

1942

104

1943

HI

1929-43 mean.
Percentage
of total.-..

1944

100
103

194.5

1946

1947

88
75
36

1948

23

1949 _

9

with conditions in recent years (table 4). Despite
the considerable fluctuations in annual yield in
the different districts to be seen in table 3, com-
ments on the 1891-1908 data* will be restricted
to the averages; we are without the information on
fluctuations in the availability of lake trout, in
the intensity of the fishery, and in other conditions,
that we need for an intelligent treatment of the
matter. Attention should be called, however, to
the distinct similarity of trends in production in
the several districts.

District M-3 strongly dominated the production
of lake trout in the State of ^lichigan waters of
Lake Michigan in 1891-1908, contributing 43.8
percent of the total output for the period. The
percentages for five of the seven remaining districts
e.xhibited only small differences, ranging from 10.3
percent for M-2 which held second position to 8.4
percent for M-7 which ranked sixth. The lowest
average yields were in M-1 (6.2 percent) and M-4
(3.2 percent). In this early period, waters north
of Grand Traverse Point (M-1, M-2, and M-3) ac-
coimted for 60.3 percent of the total output as
compared with 39.7 percent for districts M-4
through M-8.

To facilitate comparisons between the produc-
tion of lake trout in the statistical districts in
1891-1908 (table 3) and 1929-43, the"base period"
for modern statistics (table 4), a summary (table
5) has been prepared. The principal features of the
comparison are a generally lower level of take in the
more recent period, a shifting of production toward
the more southerly districts, and a lack of pro-
noimced changes in the ranking of the districts
with respect to the percentage of total yield.

Only M-5 exhibited a rise in average armual
production from 1891-1908 to 1929-13 (an increase
of 53,000 pounds). The remaining seven districts
all suffered declines that ranged from 7,000 pounds
in M-4 to the tremendous drop of 665,000 pounds
in M-3. This latter decline accounted for most of
the decrease of 885,000 poimds for the combined
districts. In no other district did the take fall by
more than 86,000 pounds (the decrease for M-2).

1 Percentage of 1929-43 mean.

' See figure 2 for the boundaries of the statistical districts.
' The term "lake" in this and the following sections has reference to State
of Michigan waters only.

• The data for 1891-1908 provide a less reliable record of production in the
individual districts than do those for 1929 and later. In the earlier period
the annual catch of each fisherman was allocated to the district in which his
home port was located, whereas in the recent period each day's catch was
credited to the statistical district in which the gear actually was lifted. The
extent to which fishermen operated outside their home districts in 1891-1908
is unlmown, but records for recent years suggest that error from this source
was not sufficiently great to affect the validity of comparisons based on tables
3 and 4,

82

FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE

STATUTE MILES

10 j 10 20 30 40 iO

Figure 2. — Statistical districts in State of Michigan waters of Lake Michigan.

DECLINE OF LAKE TROUT IN LAKE MICHIGAN

83

Table 5.-

—Comparison of average production of lake trout in Michigan statistical districts, 1891-1908 oi

id 19S9-4S

District

1891-1908

1929-43

Change. 1891

-190S to 1929-43, in—

Average
produc-
tion '

Percentage
of total

Hank

Average
produc-
tion'

Percentage
of total

Rank

Average
produc-
tion '

Percentage
of total

Rank

M 1 ---

213
352
1,500
108
340
297
289
325

6,2
10.3
43.8
3.2
9.9
8.7
8.4
9.5

7
2
1
8
3
5
6
4

146
266
835
101
393
282
224
293

5.7
10.5
32.9

4.0
15.5
11.1

8.8
11.5

7
5
1
8
2
4
6
3

-67
-86
-665
-7
-1-53
-15
-65
-32

-0.5

+.2

-10.9

-f-.8
-f5.6
+2.i

+.i
4-2.0

M 2 -

-3

M 3 _ _

M-4 __

\I-S

+1

M 6 __

+1

M 8 - - -

-1-1

3.424

100

2.640

100

-885

I Mean annual production in thousands of pounds.

The large drop in production in M-3 from 1891-
1908 to 1929-43 was reflected in a decrease of 10.9
in the percentage contribution of the district to the
total output of the State of Michigan waters (from
43.8 to 32.9 percent). The only other district in
which the percentage decreased was M-1 (a drop
of but 0.5). The remaining six districts experi-
enced increases in percentage that ranged from .2
m M-2 to 5.6 in M-5. These changes in the vari-
ous districts resulted in a noticeable shift of produc-
tion toward the south. Districts JM-1, M-2, and
M-3, which, as noted earlier, contributed 60.3
percent of the total in 1891-1908, accounted for
only 49.1 percent in 1929^3. The proportion for
M^ through M-8 rose correspondingly from 39.7
to 50.9 percent. A similar shift in production of
lake trout toward the south was described for the
State of Michigan waters of Lake Huron by Hilo
(1949).

Rather than burden the present section, which
deals with production trends in 1929-49, with
numerous micxplained exceptions to general state-
ments, it is believed desnable to anticipate discus-
sion that logically should appear later and describe
at this tune the peculiar situation in district M-1
that makes the data for that area so difficult to fit
into a general account of the lake-trout fishery of
the State of Michigan waters of Lake Michigan.
This difficulty has its origin in the circumstance
that M-1 is not true "lake-trout water" and that
the commercial catches of the species are normally
part of the production in a fishery aimed primarily
at the taking of lake whitefish (Coregonvs clupea-
formis). As a result, the intensity of the fishery
for lake trout, and consequently the production as
well, are controlled to a large degree by the condi-
tions of the whitefish fishery. This relation is
brought out rather forcefully by the data of table

933837—51 2

6 on the production, abundance, and fishing in-
tensity for the two species in M-1 over the period
1929^9.

The salient features of table 6 are summarized
briefly in the foUowing sentences. First, the pro-
duction of whitefish in M-1 normally is consider-
ably greater than that of lake trout. In only 2
of the 15 yeai-s of the base period 1929-43 was the
take of lake trout the greater, and the 15-year
average for whitefish was nearly three times that
for lake trout. In the years after 1943 the ad-
vantage of whitefish was much greater than in the
earlier, more nearly nomial period. Second, the
availability of lake trout and the intensity of the
fisher}^ for that species did not exhibit the positive
con-elation that would be expected if abundance

Table 6. — Comparison of lake-trout and whitefish fisheries in
district M-1, 1929-49

Lake trout

Whitefish

Year

Pro-
duc-
tion '

Abun-
dance
iudej '

Fishing-
inten-
sity
index >

Pro-
duc-
tion 1

Abun-
dance
index '

Fishing-
inten-
sity

index ' •

1929 - -

182

203

220

194

134

72

77

158

236

248

157

83

75

56

91

146

47
29
11
46
178
149

71
65
69
80
97
92
87
137
157
112
94
105
138
96
100

100

63
61
32
20
44
45

162
198
204
155
88
49
56
72
94
139
105
49
35
37
67

100

66
36
22
111
253
207

1,140

1,076

1,196

910

238

263

175

90

105

354

238

123

116

93

141

417

232

234

514

2.427

3,066

2.263

180
145
143
120
66
91
89
75
65
104
86
74
90
SO
92

100

114
100
148
275
221
168

199

1930

238

1931 ....

234

1932

187

1933

62

1934

46

1935

67

1936

42

1937 -

47

1938

120

1939

83

1940

37

1941

36

1942

44

1943

1929-43 mean

1944

1945

1946 _

1947

68

100

90

97

139

397

1948

629

1949

600

' In thousands of pounds

' Percentage of 1929-43 moan.

' Operations with large-mesh gill nets only.

84

FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE

Table 7.- — Correlations between abundance and fishing-
intensity indices for lake trout and whitefish in district
M-1

Indices correlated

Period '

1929-41

1929^3

1929-19

Abundance of trout : Fishing intensity for
trout

Abundance of whitefish : Fishmg intensity

-0.611
.888

-.710
.961

-.736

.779

.553
.684

-0. 553
.891

-.690
.955

-.704

.778

.514
.641

-0.316
.800

Abundance of trout : Abundance of white-
Fishing intensity for trout : Fishing inten-
sity for whitefish -

-.745
.786

Abundance of trout : Fishing intensity for
whitefish

-.250

Fishing intensity for trout : Abundance of
whitefish

Value of r at p — 05 -

.561
.433

.549

' Data given for two earlier periods as well as for entire 21 years since war-
time conditions disrupted normal trends in fishing intensity after 1941 and
the extremely low abundance of lake trout introduced a disturbing factor
after 1943.

were an important factor in deteimining the rate
of fishing; the correlation that did exist is negative
(table 7). It should be emphasized here that the
estimate of fishing intensity for a particular
species is based only on gear lifted on days when
some quantity of that species was captured. Third,
the fluctuations in fishing intensity for lake trout
followed closely those of the gUl-net fishery for
whitefish (most lake trout are captured in gill nets),
and fishing intensity for whitefish in turn was
correlated closely with the fluctuations in the
abundance of that species. The data of tables 6
and 7 thus offer rather conclusive evidence that

the availability of whitefish is of primary signifi-
cance in the determination of the intensity of the
lake-trout fishery.

The situation just described for district M-1 is
not entirely without paraUel. Hile (1949) demon-
strated that in three districts of Lake Huron in
which lake trout and whitefish ordinarily were
taken together in a "two-species fishery" (catches
of other varieties in this type of fishery are usually
imimportani) the fluctuations in the availability
of whitefish exerted a readily detectable effect on
the fishing intensity for lake trout. The condi-
tions in M-1 merely represent an extreme because
of the strongly predominant position of whitefish
in the joint fishery and also because of the tre-
mendous upturn in the abundance of whitefish and
hence in fishing intensity for both whitefish and
lake trout at a time when the availability of the
latter species was far below normal.

Comments on the 1929-49 trends of production
in the several statistical districts as recorded in
table 4 will be based largely on the summary in
the top section of table 8. Reference to the pro-
duction curves of figures 3, 4, and 5 also should
prove helpful.

A pronounced difference is to be detected be-
tween the "northern" districts (M-1, M-2, M-3)
and the remaining or "southern" districts with
respect to the calendar years of highest produc-
tion of lake trout within the period 1929-49. Of

Table 8. — Summary of -production, abundance, and fishing intensity for lake trout in Michigan statistical districts, 1929-49

Item

District

All
districts

M-1

M-2

M-3

M-i

M-S

M-6

M-7

M-8

combined

Peodcction:

1 1938

1941

1939

1941

1944

1940

1941

1946

1941

3 years cf greatest production

1 1937

1932

1931

1942

1943

1941

1942

1944

1943

I 1931

1931

1930

1944

1941

1932

1932

1945

1940

Last year with production average or greater

'1939

1943

1943

1944

1944

1942

1946

1946

1944

First year of recent progressive decline

J 1944

1944

1944

1945

1945

1941

1947

1947

1944

First year with production less than half average

> 1944

1946

1947

1947

1947

1947

•1948

1948

1947

Abundance;

( 1937

1936

1939

1943

1943

1940

1941

1942

1943

3 years of greatest abundance

{ 1941

1933

1941

1935

1944

1941

1942

1943

1941

[ 1936

1931

1932

1934

1941

1943

1943

1944

1942

Last year with abundance average or greater

1943

1941

1943

1944

1946

1946

1947

1947

1944

First year of recent progres.sive decline

•1944

• 1944

1944

1944

1944

•1944

1942

1943

1944

First year with abundance below 70 percent

'1944

1944

1946

•1947

1948

1949

1949

•1949

1947

Fishinointensitt:

( (')

1941

1930

1940

1933

1931

1931

1946

1930

.1 yenrsj nf grentp.<;t inteiritty

\ (')

1943

1931

1930

1932

1932

1932

1940

1931

I (')

1942

1938

1932

1937

1930

1930

1935

1932

T-ast year with inten'^ity average or greater ._ ,_.

(')

1944

1945

1945

1939

1941

1946

1946

1941

First year nf recent progressive decline

(')

1944

1946

1945

1947

1942

1947

1947

'1947

First year with intensity less than half average

(')

1947

1948

1948

1947

1947

1948

1949

•1949

' 1948 and 1949 production above average.
2 Decline interrupted by increases in 1947 and 1948.
' First recent year; production less than half average in 1934 and 1942.
< First recent year; production less than half average in 1936.
' Decline interrupted by increases in 1948 (followed by further slight rise
In 1949 in M-1).

• First recent year; abundance below 70-percent level in 1930 and/or 1931.

' Fishing intensity so closely linked with availability of whitefish that
summary would be meaningless and possibly misleading; see p. 83.

• 1941 if irregularities in 1944 and 1946 are ignored.

• Intensity unquestionably would have been less than 50 percent of average
In 1948 but for the abnormal situation in M-1; see p. 83.

DECLINE OF LAKE TROUT IN LAKE MICHIGAN

85

the 9 "high-production" years listed in tabic 8
for the first three districts, 8 were earlier than 1940
(the 1941 production in M-2 provided the only
exception) and 5 earlier than 1935. In districts
M— i through M-8, on the contrary, the highest

yields usually came after 1939. Only 2 of the 15
high-production years listed for the southern dis-
tricts were earlier than 1940 (1932 in M-6 and
M-7) and 10 fell within the brief 4-year period
1941^4.

O

z

3
O

0.

CO

a

<

o
o

375

M-l

/\

300

/ \

' 1

t

1

1

225

// /V\

-^^^V^

A /

ISO

- ^

/ \ / /\

\

—

/ •

^ . ,_^

N

"v

Jx

\ \ / /

75

—

\

^^^;:^^-^-n//--

1 1 1

-J

1 1 1 1 L

— ! 1 1 1 1 1 \ 1 — 1

200

— 100

M
O

<

Ul

>
<

1990

I93S

1940

1945

Z 500

o

o
o

ce
a

400

300

200

100

M-2

200

ti.

o

lil
o

<
I-
z

u

too

1930

1935

1940

1945

FlGtTBE 3. — Production, abundance index, and fishing-intensity index for lake trout in districts M-l and M-2 1929-49.
Solid line = production ; long dashes = abundance index ; short dashes= fishing-intensity index. Scale at left (thousands
of pounds) appUes only to production; scale at right is in terms of 1929-43 mean for each item.

86

FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE

1600 —

1200 —

eoo

in 400
O

z

O

0.

100

1930

1935

1940

1945

O

<
a:

UJ

>

<

IL
O

in
a

z
<
m

o

200

150 -

100

V. 50 —

Z O

O

I-

o

3 750

o
o
a.

M-4

\
\

-j^

\

1 1 1 1 1

\ 1 1

1

1 1 1 1 1 1 1

200

100

1 930

1935

1940

I94S

eoo

450

300

150

M-5

L

<

200 f-

z
u
u
ce
w
a

100

1930

1935

1940

t94S

Figure 4.— Production, abundance index, and fishing-intensity index for lake trout in districts M-3, M--4, and M-5,
1929-49. Solid line = production; long dashes= abundance index; short dashes=fishmg-intensity index, hcale at
left (thousands of pounds) applies to production only; scale at right is in terms of 1929-43 mean for each item.

DECLINE OF LAKE TROUT IX LAKE MICHIGAN

87

Soo

M-6

1930

1935

19 40

19 45

iOO

U.
O

10

a

X 300

<
in

:d
o

I

200 —

100 —

o

3 600

a

o

M-7

/3

/ .y ^^. Y/ /''\\~~\

1 1 1

1 1 1

r 1 1 r

\
1 f 1 r t 1 1 1

\
\
\
\ \
\ ^
1 N

200 n

100

1930

1935

1940

1945

450 —

300 ^^

ISO —

M-8

A

1 1 1 1 1 1 1 1

. 1 . .

1 1 1 1

\ \
\ \

.1.. 1 ^

200

CM
0>

(1.
O

o
<

o
a:

100

1930

1935

1945

Figure 5. — Production, abundance index, and fishing-intensity index for lake trout in districts M-6, M-7, and M-8,
1929-49. Solid line= production; long dashes = abundance index; short dashes= fishing-intensity index. Scale at left
(thousands of pounds) applies to production only; scale at right is in terms of 1929-43 mean for each item.

88

FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE

Despite the differences between the northern
and southern waters just outlined, all districts
agreed in showing production equal to or greater
than the 1929^3 mean in relatively recent years.
If we ignore the 1948-49 data for M-1, where, as
explained, conditions were abnormal, the situation
can be described by the statement that every
district had average or better production in 1942
or later and in two districts (M-7 and M-8) the
take was still above the mean in 1946.

The districts agreed further in that the onset
of the progressive decline which has caused so
much concern and the drop of production to less
than half the average also were recent. In only
one of the eight districts (M-6) did the recent
progressive decrease get imder way before 1944,
and in the southernmost waters (M-7 and M-8) it
did not start until 1947. With the exception of
M-1 and M-2 (again 1948-49 data are ignored in
the former district) the 50-percent level was not
passed before 1947, and in M-7 and M-8 the
take did not drop below half the mean untU 1948.
These data suggest a distinct north-to-south
trend in the time at which the decline set in.

Despite the lateness of the decline, the speed
with which it progressed was such that by 1949
the lake-trout fishery had practically come to an
end in all districts but M-1. The 1949 total catch
for districts M-2 through M-8 was only 74,000
pounds. These same waters had yielded more
than 3 million pounds as recently as 1941 and in
excess of 2 million pounds as late as 1945. The
decline since the latter year represents a decrease
of 96.7 percent.

The production data for the combined districts
may be summarized as follows: Highest yields
occurred in the early 1940's (1941, 1943, 1940);
1944 was the last year of above-average production
and the first year of the recent decline; the
output fell below 50 percent of the 1929-43
mean for the first time in 1947. Even when data
are included for M-1 where the 1949 take was
above the 1929-43 average, the decrease from
1944 to 1949 amounted to 90.6 percent.

ABUNDANCE IN STATE OF MICHIGAN
WATERS, 1929-49

The estimates of the abundance or availability '
of lake trout in the statistical districts of the State
of Michigan waters of Lake Michigan beginning

Table 9. — Abundance indices for lake trout in Michigan
statistical districts, 1929-49

[Percentages of 1929-43 mean]

Year

Abundance percentage in district—

Aver-

M-1

M-2

M-3

M-4

M-5

M-6

M-7

M-8

age '

1929

71
65
69
80
97
92
87
137
157
112
94
105
138
96
100

53
51
32
26
44
45

84

93

114

112

116

110

112

122

98

95

93

81

104

77

90

69
56
61
33
40
19

99

89
103
106

98
104
104
104

88

86
120

83
116

96
105

84
71
56
36
22
12

80
69
86
88
100
132
134
89
92
99
93
77
119
108
134

105
91
76
63
40
30

88
79
71
78
S3
93
101
93
94
97
102
110
129
126
166

146
126
97
73
60
35

89
79

77

98

107

108

116

76

78

90

102

126

125

108

121

117
113
77
72
73
43

72

79
79
110
94
79
96
76
74
78
91
126
153
161
143

139
132
115
108
89
21

74
81
66
73
88
70
81
78
96
100
101
116
119
179
178

174
166
109
106
84
33

87

1930

83

1931

87

1932

96

1933

97

1934

98

1935

102

1936

97

1937

93

1938 — —

92

1939 ---

105

1940

100

1941

123

1942

114

1943

126

1944

110

1945 — -

98

1946

75

1947

60

1948

60

1949

26

1 In the computation of the averages the abundance index for each district
was weighted by the percentage contribution of that district to the total
catch of all districts over the 15-year period 1929-43.

with 1929 (table 9; see also figs. 3, 4, and 5), are
based principally on the records of the catch per
imit lift of large-mesh gill nets (mesh sizes 4K
inches and greater, extension measure). During
the base period 1929-43, large-mesh gill nets
accounted for 88.1 percent of the total catch of
lake trout. Set hooks were second (8.2 percent),
and poimd nets third (2.2 percent). The catch
of other gears plus a small quantity of lake trout
for which gear records were lacking made up the
remaining 1.5 percent (presentation here of
original data on gear composition of the catch is
not considered necessary). Poimd nets were of
sufficient importance to be included in the estima-
tion of abundance in only three districts (M-1,
M-3, M^).

Records of the catch per unit of fishing effort
of large-mesh gill nets, set hooks, and pound nets
in the several districts in 1929-49 are given
in tables 10, 11, and 12.

In the listing of the years of highest abundance
(middle section of table 8), as was true for the
years of greatest production (top section) , distinct

' Argument about which of the two words should be employed would con-
stitute a futile quibbling over terminology. These estimates are based on
the fishing experience of the fishermen — the records of their catch of legal-sized
lalce trout per standard unit of fishing effort. They offer no uiformation on
the abundance of undersized lalce trout and are affected by such factors as
meteorological conditions, annual differences in the time of spawning in
relation to the fixed dosed season, and annual differences In the distribution
of fish. Yet, for all these obvious wealmesses they offer the best estimates
of abundance to be had at the present time. Accordingly, we do not hesitate
to use "availability" and "abundance" interchangeably.

DECLINE OF LAKE TROUT IN LAKE MICHIGAN

89

Table 10. — Catch of lake trout per lift of large-mesh gill nets
in Michigan statistical districts, 1929-49

[In pounds per li/t of 10,000 linear feet of large-mesh gill nets 4H inches and
greater, extension measure]

Year

District

M-1

M-2

M-3

M-4

M-5

M-6

M-7

M-8

1929

1930

66
67
63
78
106
73
79
168
189
121
96
118
134
91
94

102

50
48
30
24
42
44

126
143
175
171
169
168
166
184
146
142
142
121
161
115
136

151

105
81
78
49
61
28

13!

117
140
143
122
127
136
136
113
113
161
109
155
125
138

131

109
92
73
47
29
16

83
66
90
88
88
153
138
97
92
106
101
80
126
118
143

105

109
92
80
65
42
31

84
77
72
80
86
96
103
94
95
99
103
113
131
127
158

101

147
126
98
73
61
35

98
86
84
107
119
118
127
82
85
98
113
139
137
118
130

109

129
124
84
79
80
47

99
111
139
201
140
126
188
148
143
181
189
276
264
247
234

179

219
212
189
189
143
34

85
108

1931

92

1932

138

1933 -

1934

138
91

1935

1936 — - — -

128
149

1937

163

1938 — - -

177

1939

184

1940

212

1941 .

196

279

1943.

260

1929-^ mean

160

1944 _.

258

1945 --

239

1946

158

1947

150

1948

1949

122
48

Table 12. — Catch of lake trout per lift of pound nets in
Michigan statistical districts, 1929-49

(In pounds per lift of 1 pound net. Where no figures are given, few or no lake
trout were talcen with this gear]

Table 11. — Catch of lake trout per lift of set hooks in
Michigan statistical districts, 1929-49

[In pounds per lift of 1 .000 set hooks. Where no figures are given, few or no
lake trout were taken with this gear]

Year

District

M-1

M-2

M-3

M-4

M-5

M-6

M-7

M-8

1929

223

253
201
151
197
247
237
165
154
129
138
1-29

173
111

187
218
290
198
259
236
215
207
158
190
91

133
143

118
132
229
264
161
182
114
61
111
104
102

137
119
123

94
172
139
147

96
191
131

83
143

73
107

356

247
208
138
165
162
202
275
218
433
117
120

131

108
122
131
72
112
120

"56'

239
194
132
191
201
154
143
117
122
123
153
134
137
173
249

164

346
211

185
74

252

1930 -

194

1931

145

1932

116

19.33

132

1934 . __.

200

1935

162

1936

112

1937

133

19.38

140

1939

161

1940

158

1941

176

1942

102

212

1943

265
121

323

1929-43 mean'

184

190

143

128

140
167

243

174

1944. -

73

1945

1946

208

1947

~i?)"

""(".)"

435

1948 —

""(.)-"

~m"

~m"

65

1949

C)

(»)

' For each district for which data are not given for 1 or more years, the
15-year average is estimated by dividing the mean of the available annual
averages by the mean of the abundance percentages for the same years. See
Van Oosten, Hile, and Jobes (1946) for comments on the estimation of a
normal catch when data are not available for all years.

" No fishing with set hooks in 1949.

diflFerences are to be seen between the northern
and southern areas of the lake. Of the 12 "high-
abundance" years listed for districts M-1 through
M-4,* 9 were earlier than 1940 and only 1 was

» District M-1, assigned to the southern districts in the grouping with
respect to production, has been assigned to the northern with respect to years
of greatest abundance.

Year

District

Year

District

M-1

M-3

M-f

M-1

M-3

M-4

1929

14
15
13
18
16
29
23

8
13
16
12

8

17
16
15
16
25
17
20
17
22
15
11
9

21
27
22
43
47
38
66
24
33
17
13
16

1941

13

12
8
12

16

13
16
10
4

3

1

19

1930

1942

23

1931

1943

2
14
4

18

1932—

1929-43 mean'..

1944

1945

1933

28

1934

1935..

9

1936

1937

1946

10

1938

1947-^ —

9
8
S

2

1939

1948 —

1949

7

1940..

' For each district for which data are not given for 1 or more years, the 15-
year average is estimated by dividing the mean of the available annual aver-
ages by the mean of the abundance percentages for the same years. See
Van Oosten, Hile. and Jobes (1946) for comments on the estimation of a nor-
mal catch when data are not available for all years.

later than 1941. The corresponding record for
districts M-5 through M-8, on the contrary,
shows all 12 years within the period 1940-44
and 9 within the still-shorter interval 1941—43.

Although the recent progi-essive decline in
abundance appears to have started at much the
same time in all districts (1942 in M-7, 1943 in
M-8, and 1944 in all other districts) it proceeded
much more rapidly in northerly than in southerly
waters. The last year with abundance at average
or greater was 1941 in M-2, 1943 m M-1 and M-3,
1944 in M-4, 1945 m M-5 and M-6, and 1947 in
M-7 and M-8. The same north-to-south sequence
exists in the first year in which abimdance dropped
below the 70-percent level,' 1944 in M-1 and
M-2, 1946 in M-3, 1947 in M^, 1948 m M-5,
and 1949 in M-6, M-7, and M-8. This north-
to-south progression resembles closely that de-
scribed for production in the preceding section.
The situation invites speculation about the
possibility that a southward spread of the sea
lamprey was a contributmg factor.

Despite the differences in timing just described,
the districts agreed in that all showed an ex-
tremely low level of availability of lake trout in
1949 (range of abimdance percentages from 45 in
M-1 down to 12 m M-3). Admittedly, the
dependability of the estimates of abundance
decreases rapidly as production falls to low levels.
Nevertheless, the consistently low returns per

• The 70-percent level Is considered preferable here to the 50-percent flgiu^
employed for analogous items In the data for production (and for fishing
hitensity, discussed later). Usually the fishery has all but disappeared by
the time the 60-porcent level of abundance is reached.

90

FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE

unit of fishing effort together with the very fact
that production had all but ended in most areas
must be accepted as conclusive evidence of the
great scarcity of marketable-sized lake trout in
the State of Michigan waters of Lake Michigan in
1949.

For the combined districts the level of abun-
dance was highest in 1943 (126), 1941, and 1942.
The last year with abundance above average and
the first year of the recent progressive decline
was 1944, and abundance first dropped below the
70-percent level in 1947. In 1949 the abundance
had reached the low figure of 26 percent.

Table 13. — Correlations between 1929-43 fluctuations in
abundance indices for lake trout in Michigan statistical
districts

[Values of r corresponding to probabilities p of 0.05 and 0.01 are ±0.514 and
±0.641]

District

District

M-1

M-2

M-3

M^

M-6

M-6

M-7

M-8

M-1

0.113

'"7370
.181
-.460
-.255
-.374
-.617

-0.040

.370

.404
.181
.233
.201
-.037

0.175
.181
.404

"7587
.591
.394
.365

0.346

-.460

.181

.587

"".m

.786
.889

0.043

-.256

.233

.591

.681

--"767
.526

0.142
-.374
.201
.394
.786
.767

-"165

223

M-2

0.113
-.040
.175
.346
.043
.142
.223

-.617

M-3

-.037

M-4

.365

IM-5

.889

M-6

M-7

M-8

.626
.805

From earlier discussion and from the examina-
tion of table 9 and figures 3, 4, and 5, it is apparent
that in certain districts the annual fluctuations in
the abundance of lake trout followed similar
trends. In the northern waters for example, it
has been pointed out that most of the years of
highest abundance fell before 1940, whereas the
southern districts shared a period of high avail-
ability in the early 1940's. To provide a more
precise measurement of the agreement in these
trends, coefficients of correlation were computed
for the abundance percentages for aU pairs of
districts over the period 1929-43. Data for
yeare later than 1943 were excluded in order to
minimize or possibly eliminate the distorting
effects of the decline in abundance that followed
the depredations of the sea lamprey in all districts.
This restriction, we believe, has made the coeffi-
cients recorded in table 13 relatively reliable
estimates of the correlations between fluctuations
in the availability of lake trout in the difl'erent
districts under approximately "normal" condi-
tions.

The outstanding feature of the data of table
13 is the close positive correlation among the
fluctuations in abundance in the four southern
districts (M-5 thi-ough M-8). Of the sLx coeffi-
cients that could be computed for these districts,
five exceeded the value ordinarily accepted as
"higlily significant" (p<^0.01), and the sixth was
above the level ordinarily termed "significant"
(^<0.05). These high values, together with the
consistency with which they occurred with all
possible pairings, suggest strongly that the lake-
trout fisheries to the south of Grand Traverse
Point were based on a common stock or on stocks
in which the factors controlling abundance in
1929-43 were the same or subject to sunilar
annual fluctuations. Further speculation in the
matter would be to little point until we have
definite information on the nature of these factors
and the methods by which they operate.

The fluctuations of abundance in M-4 exhibited
positive significant correlation with those in the
two districts immediately to the south (M-5
and M-6). The correlation with fluctuations in
M-3 also was positive but the value of the coeffi-
cient (r= 0.404) was well below the level of
significance.

Of the 3 coefficients computed between districts
M-1, M-2, and M-3, and the 15 calculated
between those districts and the ones lying farther
south, only one was significant (r= — 0.617, M-2
and M-8). This single significant value in a
group of 18 faUs to fit the pattern. The weight
of the evidence suggests that the fluctuations in
the abundance of lake trout in each of the three
northern districts were not correlated with those
ia the remaining ones.

FISHING INTENSITY IN STATE OF
MICHIGAN WATERS, 1929-49

The records of the annual fluctuations in the
intensity of the fishery for lake trout (table 14;
figs. 3, 4, and 5; bottom section of table 8) fail
to reveal the distmct separation with respect to
trends that existed between northern and southern
areas in production and abundance. With the
exception of M-2 where all three years and M-8
where two of the three years of most intensive
fishing occurred in the 1940's, the tendency was
general for fishmg operations to be heaviest in the
early 1930's. Of the 21 "high-intensity" years
listed in table 8 (see section on production in the

I

DECLINE OF LAKE TROUT IN LAKE MICHIGAN

91

Table 14.-

-Intensity of fishery for lake trout in Michigan
statistical districts, 1929-49

[In units corresponding to 1/1500 of total eipected catch for all districts over

15-year period 1929-43]

Year

District

Tota

M-1

M-2

M-3

M-4

M-5

M-6

M-7

M-8

19M ..

10.1

7.1

36.8

3.4

11.9

12.7

8.3

9.5

98.8

1930

12.3

9.7

42.9

6.2

14.0

13.3

11.5

13.0

121.9

1931 ..

12.7

10.1

38.3

4.7

17.3

14.6

12.7

9.1

119.6

1932 .

9.6

11.4

32.7

5.2

19.2

14.1

11.5

8.6

112.3

1933

5.4

10.0

27.3

4.1

20.9

11.1

S.9

9.1

96.8

1934

3.1

9.8

25.1

2.2

15.8

10.1

7.5

9.4

83.0

1935

3.4

8.4

28.9

2.6

16.7

10.3

9.5

14.5

94.3

1936

4.6

8.3

30.8

3.3

15.1

7.4

5.8

9.6

84.8

1937... .

5.8

11.8

32.8

3.8

18.6

7.4

6.9

7.3

94.4

1938

8.6

9.9

36.4

4.6

17.4

7.9

7.4

11.8

104.0

1939

6.5

9.8

33.9

4.2

15.6

10.1

8.4

14.3

102.8

1940

3.1

10.6

34.8

6.5

15.1

13.0

8.9

16.5

107.5

1941.

2.1

13.3

30.3

4.6

13.5

12.9

10.6

14.1

101.4

1942

2.3

12.9

28.1

4.8

11.9

10.2

8.8

11.1

90.1

1943

3.6

13.0

31.0

3.6

11.3

8.8

5.8

11.4

88.4

1929-43 mean...

6.2

10.4

32.6

4.1

15.6

10.9

8.9

11.3

100

1944

3.5
2.2
1.4
6.9
15.7

11.0

10.0

6.0

3.0

2.4

31.6
32.8
31.1
23.9
15.8

4.9
4.1
3.5
2.4
1.8

12.3
9.3

10.5
6.8
5.6

8.3

7.8
7.7
3.8
1.0

7.3

7.3
9.9
5.6
1.9

13.1

13.7

21.2

8.7

6.1

91.9

1945

87.2

1946...

91.3

1947

61. 1

1948

50.3

1949

12.8

.7

7.4

1.7

2.4

.4

.4

.7

26.5

various districts for an account of the unusual
situation ia M-1) 12 fell within the 4-year period
1930-33.

The last year of average or greater fishing
intensity was 1939 in M-5, 1941 in M-6, and 1944
to 1946 in the remaining districts. The recent
progressive decline started in 1942 in M-6 and in
1944 to 1947 in other areas. Fishing intensity
first dropped below the 50-percent level in 1947
m M-2, M-5, and M-6, in 1948 in M-3, M^, and
M-7, and m 1949 in M-8.

For the combined districts the intensity of the
lake-trout fishery was greatest in 1930, 1931, and
1932, and the last year of greater-than-average
intensity was 1941. The recent progressive de-
cline started in 1947, and in 1949 fishing intensity
was only 26 percent of the 1929-43 mean.

The factors that influence the intensity of the
fishery for lake trout are so numerous, so variable
in their effects, and so difficult to appraise, that in
most situations it is impossible to evaluate the
effect of any one of them. Among these factors
may be listed: Weather conditions; costs of
operation; availability of and market for lake
trout, for species taken along with lake trout, and
for species produced alternatively. During the
war years scarcities of equipment and supplies
and manpower shortages also affected fishing
intensity.

The availability of the lake trout itself well
might be expected to exert an important influence

on the intensity of fishing since good catches per
unit of effort shoidd stimulate fishing operations
and poor lifts depress them. This expectation
is not borne out, however, by the following
tabulation of the coefficients of correlation between
the abundance of lake trout and fishing intensity
for the species in the various districts in 1929^1 :""

r

District M-1 -0. 611

District M-2 .034

District M-3 -. 378

District M-4 -. 677

r

District M-5 -0. 379

District M-6 . 225

District M-7 .357

District M-8 . 633

Of the eight coefficients calculated, four were
positive and four negative, and of the three that
were "significant" (r= ±0.553 at the 5-percent
level of probability) one was positive and two
negative. It is not to be concluded, of course,
that a plenitude of lake trout is about equaUy
likely to stimulate or depress fishing activity;
rather, it should be stated that in many situations
other factors are of greater importance.

The high negative correlation between fishing
intensity and abundance of lake trout in M-1
has already been explained. The available sta-
tistical data do not suggest an explanation of the
even higher negative figure for M-4. Perhaps
this significant correlation was merely fortuitous.
We are inclined to suspect, however, that the neg-
ative correlation can be attributed in part to
changes of fishing grounds during the time of the
great increase in the popularity of "deep-sea'
troUing for lake trout in Grand Traverse Bay
(identical with M^) in the 1930's. Although we
have no quantitative measure of the effect on the
intensity of the fishery, we do know that certain
fishermen, in an attempt to lessen friction between
sport and commercial interests, avoided the sport-
trolling grounds during the peak of the tourist
season and moved their operations to grounds
north of Grand Traverse Point (M-3) and near
Cathead Point (M-5). Consequently, fishing in-
tensity may have been lower than normafly would
be expected in some years when lake trout were
relatively plentiful.

The significant positive correlation between
fishing intensity and the abundance of lake trout
in M-8 may reflect a true cause-and-effect rela-

'0 The elimination of years after 1911 in these computations makes possible
the best estimate of rel.itions under approximately "normal" conditions since
bias from wartime shortages of manpower and materials and the effects of the
general sharp deline in abundance that accompanied the increase in the
population of sea lampreys in recent years are eliminated or minimized.

92

FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE

tion, but the lack of a simOar correlation in the
other districts throws some doubt on such an
interpretation.

The general situation in the State of Michigan
waters seems to be much the same as that in the
United States waters of Lake Huron where Hile
(1949) concluded that "indispensable as the lake
trout may be to the conduct of a lake trout
fisheiy, the abundance of that species is only one
of the factors, and in some situations a subordinate
factor, in the determination of fishing intensity."

RELATIONS OF PRODUCTION,
ABUNDANCE, AND FISHING INTENSITY

Considerable infoi-mation on the relations of
production, abundance, and fishing intensity in
the lake-trout fishery of the State of Michigan
waters of Lake Michigan was given in the preced-
ing sections. The discussion of the present sec-
tion is restricted largely to the question of the ex-
tent to which production has served as an indica-
tor of fluctuations in the abundance of lake trout
and to changes in the fishery immediately pre-
ceding and dm-ing the recent collapse, with special
reference to the possible role of overfishing as a
factor in the decline in abmidance of lake trout.

The accumulation of information on the degree
of reliability of production statistics as indicators
of changes in abundance or availability in the
Great Lakes fisheries is of importance because in
many areas data on the actual take per unit of
fishing effort are not available or are at hand for
only the more recent years.

The opinion was expressed by Van Oosten, HUe,
and Jobes (1946) that "imder normal conditions
(without disruption in the methods or regulations
of the fishery), over limited areas, and for short
periods of years, large increases or decreases of
production may serve as reliable indicators of in-
creases or decreases in the abundance of fish on
the grounds." A similar view was held by Doan
(1942) who considered it valid to employ catch
statistics for the estimation of the fluctuation in
the abundance of several commercially important
species in Lake Erie. Doan based his opinion
largely on the agreement between trends in the
catch of walleyes or yellow pikeperch {Stizostedion
V. vitreum) per unit effort in the principal gear and
the total production of the species in four fishing
areas of Lakes Huron and Michigan (data for these

two lakes adapted from Hile 1937) and in Lake
Erie. More recently, Hile (1949) demonstrated a
significant positive correlation between annual
fluctuations in the production and abundance of
lake trout for four of the sLx statistical districts of
the United States waters of Lake Huron and for
the six districts combined. In a fifth area the co-
efhcient was positive with a value corresponding
to the 10-percent level of probabihty, but a sig-
nificant negative value existed in the sixth district.
This negative correlation was explained as the
result of the depressing effect of the collapse of the
whitefish fishery on the intensity of operations with
large-mesh gill nets dui'ing years of relatively high
abundance of lake trout (note the similar situation
described earlier in this paper for district M-1).

Of the coefficients of correlation between the
production and abimdance computed for Lake
Michigan (table 15) those for the period 1929-41
most nearly reflect "normal" conditions. The co-
efficients for the base period 1929-43 were prob-
ably biased by the depressing effects of wartime
scarcities of manpower and equipment and those
for 1929—49 were affected by wartime conditions
and more recently by the general collapse of the
lake-trout fishery.

Table 15. — Correlations between production and abundance
of lake trout in Michigan statistical districts, for 3 periods

Item

Period

1929-41

1929-43

192949

-0. 050
.614
.431
.065
.677
.775
.904
.874
.579

.476
.553
.684

-0.028
.516
.441
.223
.528
.714
.817
.878
.696

.441
.614
.641

0.337

District M-2

.914

District M-3 _.

.937

.712

District M-5

.708

District M-6

.802

District M-7

.802

District M-8

.872

All districts

.918

Value of r at p — 0.10

.369

.433

.549

Actually, the differences between 1929-41 and
1929-43 were unimportant. In both periods the
correlations between production and abimdance
were "highly significant" (p<0.01) for M-6, M-7,
and M-8 and were "significant" (0.05>p>0.01)
for M-2 and M-5 and for the combined districts.
The positive coefficients for M-3 were moderately
high but nevertheless fell short even of the 10-per-
cent value in 1929-41 and barely attained that
level in 1929-^3. The 1929-41 and 1929^3 data

DECLINE OF LAKE TROUT IN LAKE MICHIGAN

93

5.000 F

a

z

o

a
z
<

D
O

X

o
O

3,000 -

2.000 —

1,000 —

1930

1935

1940

1945

Figure 6. — Production, abundance inde.x, and fishing-intensity inde.x for lake trout in combined districts of State of
Michigan waters, 1929-49. Solid line = production; Iohr dashes = abundance index; short dashes = fishing-intensity
index. Scale at left (thousands of pounds) applies to production only; scale at right is in terras of 1929-43 mean for
each item.

offer no evidence for a correlation between the pro-
duction and abundance of lake trout in M-1 and
M-4. A negative correlation between abundance
and fishing intensity in each of the two districts in
1929-^1 (see preceding section) imquestionably
was a major disturbing influence.

From the values of the coefficients for 1929-^1
and/or 1929-43 it appears that production served
as a more or less reliable indicator of at least the
more significant fluctuations of abundance in five
of eight districts and in the lake as a whole, was
of highly limited value in one district and was com-
pletely undependable in two (see figs. 3, 4, 5, and
6). The failm-e of production and abundance to
follow similar courses in M-1 and M-4 (to a con-
siderable extent in M-3 also) brings out the impor-
tance of being constantly alert to identify and, if
possible, evaluate distmbing factors in the use of
production figures for detecting changes in abun-
dance. It should be stressed also that catch statis-
tics should be employed only to detect changes of
abundance and not as measures of those changes.

The coefficients of correlation for 1929-49 had
high positive values — far beyond the level accepted
as higlily significant — in districts M-2 through
M-8 and in the combined districts. District M-1 ,
where abnormally intensive fishing kept produc-
tion high in later years, offered the single excep-
tion. These high values for districts M-2 through
M-8 can be attributed to the enormous declines
in both production and abundance that occiured
in the later years of the period. Too much should
not be made of the high coefficients for 1929-49 as

an argmnent for the value of production statistics
for following trends of availabihtj'. When a
fishery suffers a decline as disastrous as the one
that has overtaken the lake-trout fishery of Lake
Michigan, statistical analyses are hardly required
to prove that fish are too scarce to support com-
mercial operations.

During the years of the decline in the lake-trout
fisheries of Lakes Huron and Michigan we heard
the opinion expressed both privately and publicly
that the sea lamprey had not contributed signifi-
cantly to the collapse, that the stocks of lake trout
simply had dwindled away under the pressure of
overfishing, that the distress of the fishing industry
was but just retribution for a wanton despoliation
of a valuable public resource. The facts given in
an earlier study of the lake-trout fishery of Lake
Huron (Hile 1949) demonstrated rather conclu-
sively that excessive fishing intensity could not
have brought about the collapse of the fisheiy in
the United States waters of that lake. Corre-
sponding data for the State of Michigan portion
of Lake Michigan compel a similar conclusion for
the lake-trout fishery of those waters.

The data of table 16 (see also fig. 6) fail com-
pletely to show a level of fishing intensity that
would account for the recent decline in the lake-
trout fishery of Lake Michigan. On the contrary,
the most intensive fishing operations of the 21-year
period, 1929^9, occurred m 1930-32 (112 to 122
percent of the 1929-43 mean — figures that do not
indicate excessive fishing even at that time)
whereas in the later years fishing intensity has

94

FISHERY BtTLLETESr OF THE FISH AND WILDLIFE SERVICE

Table 16. — Indices of production, abundance, and fishing
intensity for lake trout in Slate of Michigan waters, 1929-49

[Percentages of 1929-43 means]

Year

Produc-

Abun-

Inten-

Year

Produc-

Abun-

Inten-

tion

dance

sity

tion

dance

sity

1929 __

86

87

99

1940

109

100

108

1930 -

101

83

122

1941

126

123

101

1931

104

87

120

1942

104

114

90

1932

108

96

112

1943

111

126

88

1933 -

94

97

97

1944

103

110

92

1934

81

98

83

1945

88

98

87

1935

96

102

94

1946

75

75

91

1936

84

97

85

1947

36

60

61

1937

89

93

94

1948

23

50

50

1938

98

92

104

1949

9

26

26

1939

109

105

103

been invariably below the 100-percent value since
1941. It is particularly significant that intensity
was below average in 3 of the 4 years of highest
abundance (1941-44) and was barely above the
15-year mean in the fourth. These same years
saw production consistently above the mean and
at a 21 -year peak in 1941, but a high level of
abundance, not intensive fishing, was the cause.
Furthermore, the intensity percentage exceeded
the abundance percentage in only 2 of the 9 years
of the period 1941-49; in the remaining 7 years
the two index figures were the same or fishing in-
tensity was the lower. It is thus obvious that a
rate of fishing that could bring the index of
abimdance from a record high figure of 126 in

1943 to a record low value of 26 in 1949 simply
did not exist. Some factor other than overfishing
caused the lake trout to disappear in Lakes Huron
and Michigan. The best evidence points to the

sea lamprey.

SUMMARY

After a developmental period from 1879 through
1889, the fishery for lake trout, Salvelinus [=Cris-
tivomer] namaycush, in Lake Michigan entered on
a 22-year period (1890-1911) of high and rela-
tively stable production. The average annual
output for this latter interval was 8,230,000
pounds. There followed two shorter intervals of
15 years (1912-26) and 13 years (1927-39) in
which the annual yields were still moderately
stable but had successively lower average values
of 7,007,000 and 5,293,000 pounds. Production
rose in 1940 but the heightened prosperity was
short-lived. After 5 years (1940-44) in which the
yield was consistently more than 6 million pounds
and averaged 6,578,000 pounds, the lake-trout
fishery suffered a calamitous decline which saw
the annual catch drop from 6,498,000 pounds in

1944 to only 342,000 pounds in 1949.

Michigan and Wisconsin have always contrib-
uted the bulk of the production of lake trout in
Lake Michigan. The contribution of Michigan
for the periods listed in the preceding paragraph
(excluding the developmental years for which only
scattered data were available) ranged from 42.4
percent in 1890-1911 to 45.7 percent in 1927-39.
In Wisconsin the range was from 41.4 percent in
1940-44 to 54.8 percent in 1890-1911. The per-
centages have been consistently small for Indiana
(maximimi of 3.1 percent in 1912-26) and were
smaU for Illinois also in the earlier years. More
recently Illinois contributed 14.7 percent of the
total for the lake in 1940-44 and 11.3 percent in
1945^9.

Comparison of the aimual yields of lake trout
in the eight statistical districts of the State of
Michigan waters of Lake Michigan in 1891-1908
with those of 1929-43 (the base period for our
modern statistical analyses) revealed a lower
level of productivity in more recent years for
every district but M-5 and a slight southward
shifting of the centers of production (the north-
erly districts M-1 through M-3 contributed
60.3 percent of the 1891-1908 total but only
49.1 percent of the 1929-43 yield). The ranking
of the districts with respect to their percentage
contribution to the lake total changed little,
however.

Production statistics for the individual dis-
tricts in 1929-49 showed that most of the years
of relatively high production (the three best
years for each district) fell before 1940 in north-
erly waters (M-1 through M-3) and after 1940
in southerly waters (M-4 through M-8). Al-
though the recent progressive decline in produc-
tion got under way earlier than 1944 in only one
district and started as late as 1947 in M-7 and
M-8, the catch had dropped to an insignificantly
low level in all districts by 1949 (an exception
must be made for M-1 where considerable quan-
tities of lake trout were taken coincid en tally in
an abnormally intensive fishery for whitefish).

Records of the three years of greatest abun-
dance or availability of lake trout (as computed
from the data on the catch per unit of fishing
eft'ort of the principal gears) revealed that most of
these years fell before 1940 in districts M-1
through M-4, whereas in the waters to the south
(M-5 through M-8) they all fell within the period
1940^4. Figures on the last year with abun-

DECLINE OF LAKE TROUT IN LAKE MICHIGAN

95

dance at or above the 1929^3 index of 100 and
on the first year of abundance below 70 (a level
of availability selected as critical in this study)
give strong indication of a north-to-south pro-
gression in the timing of the recent decline (wTth
the more northerly districts the first to drop below
average and to pass the 70-percent level). This
sequence suggests that the different areas may
have been affected successively as the sea lamprey
spread from the north to the south. Despite this
progression, all eight districts agreed in exlii biting
an extremely low level of abundance in 1949 (from
12 to 45 percent of average in the individual
districts; 26 percent for the combined districts).

During the more nearly normal years preceding
the recent general decline of the lake-trout fishery,
the annual fluctuations in the abundance of lake
trout in the four southern districts (M-5 through
M-8) were closely correlated. The coefficient of
correlation r was highly significant (p<C0.01) for
five of six possible pairings over the period 1929-43
and was significant (p<0.05) for the sixth. The
fluctuations of abundance in M-4 also were coiTe-
lated significantly with those in M-5 and M-6.
The abimdance in each of the northern districts,
on the contraiy, appeared to be independent of
that in any other area.

In the majority of the statistical districts the
years of most intensive fishing for lake trout fell
in the early 1930's and for the combined districts
the three years of greatest fishing intensity were
1930, 1931, and 1932. With the exception of M-1,
where a recent upswing in the intensity of fishing
for whitefish led to an increased pressiu-e on lake
trout, fishing intensity for the latter species en-
tered on a progressive decline as early as 1942 and
in no district later than 1947. By 1949, fishing
intensity was far below 50 percent of the 1929^3
average in aU districts but M-1 and amoimted to
only 26.5 percent for the eight districts combined.
The abundance of lake trout seems to have had
little influence on the intensity of the fishery under
the nomial conditions of 1929-41 (before World
War II with its shortages of manpower and equip-
ment and well before the general decline of the
lake-trout fishery associated with the spread of
the sea lamprey) .

Dming the same normal 1929^1 period, fluc-
tuations in production served as reasonably de-
pendable indicators of major changes in abundance
in five of the eight districts. These changes in

production did not, however, provide rehable
measures of the extent of the fluctuations in
abundance.

Statistics on the production and abundance of
lake ti'out and on the intensity of the lake-trout
fishery refute the view sometimes advanced that
overfishing has been the cause of the decline of
the lake trout in the State of Alicliigan waters of
Lake Michigan. The most intensive fishing of
the 1929-49 period took place in 1930-32, and
intensity has been consistently below the 1929-43
average since 1941. Some factor other than over-
fisliing caused the lake trout to disappear. The
best evidence points to the sea lamprey.

LITERATURE CITED

Do.\N, Kenneth H.

1942. Some meteorological and limnological
conditions as factors in the abundance of
certain fishes in Lake Erie. Ecol. Mon.,
vol. 12, pp. 293-314.

Gallagher, Hubert R., and John Van Oosten.

1943. Supplemental report of the United
States members of the International Board
of Inquiry for the Great Lakes Fisheries.
International Board of Inquiry for the
Great Lakes Fisheries — Report and Sup-
plement, pp. 25-213.

HiLE, Ralph.

1937. The increase in the abundance of the
yeUow pike-perch, Stizostedion vitreum (Mit-
chill), in Lakes Huron and Michigan, in
relation to the artificial propagation of the
species. Trans. Amer. Fish. Soc, vol.
66 (1936), pp. 143-159.

1949. Trends in the lake trout fishery of
Lake Huron through 1946. Trans. Amer.
Fish. Soc, vol. 76 (1946), pp. 121-147.
Hile, Ralph, and Frank W. Jobes.

1941. Age, growth, and production of the

yeUow perch, Perca flavescens (Mitchill),

of Saginaw Bay. Trans. Amer. Fish. Soc,

vol. 70 (1940), pp. 102-122.

Van Oosten, John, Ralph Hile, and Frank W.

Jobes.

1946. The whitefish fishery of Lakes Huron
and Michigan with special reference to the
deep-trap-nct fisheiy. Fisheiy Bull., U. S.
Fish and Wildlife Service, vol. 50, pp.
295-394.

O

UNITED STATES DEPARTMENT OF THE INTERIOR, Oscar L. Chapman, Secretary
FISH AND WILDLIFE SERVICE, Albert M. Day, Director

I

CHARACTERISTICS OF SPAWNING NESTS
OF COLUMBIA RIVER SALMON

\

By Clifford J. Burner

FISHERY BULLETIN 61

From Fishery Bulletin of the Fi*h and Wildlife Service

VOLUME 52

UNITED STATES GOVERNMENT PRINTING OFFICE

WASHINGTON

1951

For sale by the Superintendent of Documents, U. S. Government Printing Office, Washington 25, D. C.

Price 20 cents

CONTENTS

Page

General life history 97

Criteria of a mature redd 97

Measurements and methods 100

Chinook salmon 102

Spring Chinook 102

Summer chinook 103

Fall ciiinook 103

Silver salmon 106

Chum salmon 106

Blueback salmon 107

Redd size and interredd space 107

Summary 110

Literature cited 110

CHARACTERISTICS OF SPAWNING NESTS OF COLUMBIA

RIVER SALMON

By Clifford J. Burner, Fishery Research Biologist

GENERAL LIFE HISTORY

Construction of Grand Coulee Dam across the
main stem of the Columbia River raised a serious
problem concerning the salmon that spawned in
the upper reaches of the river and produced an
important part of the west-coast catch. Grand
Coulee was to be a high dam, with a tailrace-
forebay difference of about 350 feet. Although it
was possible to provide reasonably safe passage
upstream past the dam for the adult salmon, the
cost would be extremely high. Of greater im-
portance was the probability that the salmon
fingerlings on their way to the sea would be killed
in passing down the spillway or through the tur-
bines. It was decided, therefore, to relocate the
salmon rims that spawned above the Grand Coulee
site in four tributary systems entering the Colum-
bia River below that site. The Wenatchee, En-
tiat, Methow, and Okanogan Rivers were selected
to receive the transplanted salmon.

One of the manj' questions in connection with
the relocation was how many salmon should be
placed in each stream or section of stream to get
the maximum yield of spawn and frj'. To answer
this question, a study was made of the spawn-
ing habits of four species of Pacific salmon of
the genus Oncorhynchus. These are the chinook
(0. tschawytscha) , the silver (0. kisutch), the chum
{0. keta) , and the blueback {0. nerka) . This study
was concerned particularly with the type of
stream bottom that a given species uses for spawn-
ing, and the space occupied by a pair of spawning
fish for the nest, or redd. The study included
redds of salmon spawning naturally in some of the
lower Columbia River tributaries and redds of
transplanted spawners in the foster rivers. The
information obtained was used in planning and
carrying out the maintenance project (Fish and
Hanavan 1948) but was not published.

At this time, in view of the program for the
development of the lower Columbia River tribu-
taries in the interest of salmon production, it
seems worth while to set forth the results of the
study so that they may be available for reference.

All species of Pacific salmon are anadromous,
that is, the adults migrate from the ocean into
fresh-water streams to spawn. They proceed up
rivers, such as the Columbia, until they arrive at
the same tributary where they themselves began
life some years before. Verj' few stray to other
streams. The female salmon deposits her eggs
in a nest, or redd, which she digs in the gravel of
the stream or shallow lake-shore waters. In the
process of egg laj-ing, the fertilized ova are covered
with successive layers of gravel to a depth of
several inches. The time required for the eggs to
hatch depends on the temperature of the water.
Newly hatched fish live in the gravel of the redd
and gradually absorb the food in the abdominal
yolk sac. At the end of this period, usually in the
late winter or early spring, they struggle up through
the gravel and begin to seek food. How long the
young fish stay in fresh water varies considerably
with the species, but eventually they migrate
downstream to the sea, where they remain from 1
to 3 years and grow rapidly. When they approach
sexual maturity, they return to fresh water to
spawn and thereby complete the cycle. All
Pacific salmon die after spawning.

CRITERIA OF A MATURE REDD

At the outset of this study, it was necessary to
determine at which stage of development a redd
should be measured. Redd building may be
divided into three stages, prespawning, spawning,
and postspawning. During the prespawning stage,
the female salmon is green, that is, the eggs are
neither ripe nor loose in the ovaries. Males are
seldom in attendance, and are frightened away by
the female, who repels all intruders of either sex.
The female digs the redd as she turns on either
side, at an angle of about 45° to the current, head
upstream, body arched, and makes a series of
violent flexions with body and tail. (See fig. 1.)
The tail strikes the gravel occasionally and the
strong-boiling current created carries gravel and

97

aistM O - il

98

FISHERY BULLETIN OF FISH AND WILDLIFE SERVICE

I /oor'

Figure 1. — Redd making. Female digging.

Figure 2. — Typical currents in a redd.

silt a short distance downstream. This material
spreads out in a flat semicircle at first; then, as the
digging upstream proceeds, it collects into a loose
pile called the tailspill. With more digging, the
redd assumes a long oval shape about twice the
length of the salmon and several inches deep.
The prespawning digging of the redd may go on
for as many as 5 days.

At the beginning of the spawning stage, the nest
is ready for the eggs. All loose gravel and fine
material have been removed from the pot, or
center of the redd, whose shape is such that any
current in the bottom flows upstream (see fig. 2),
then upward and outward. Usually there remain
in the pot large stones too heavy for the fish to
move far, and the crevices between these rocks
provide excellent lodgment for the eggs. Males

are constantly present now. The female alter-
nately digs at the redd and settles back into the
depression to release eggs. A male then moves
quickly alongside the resting female, as in figure 3,
curves his body against hers, and releases sperm
in a small milky cloud that settles briefly in the
bottom of the redd where the eggs are lodged.
The newly deposited eggs are thus surrounded by
sperm and eventually fertilized. Excess sperm is
carried slightly upstream along the bottom of the
redd and gradually carried away by the current.
During the spawning stage the redd increases
considerably in length and depth, and appears to
move upstream as a result of the continued digging
at the upstream wall and the filling in of the tail-
spill area.

The postspawning stage begins after the female

CHARACTERISTICS OF SPAWNING NESTS OF COLUMBIA RIVER SALMON

99

o::5-^cD-^cU^

o

r

Figure 3.-

-A pair of spawning salmon on a redd.

100

FISHERY BULLETIN OF FISH AND WILDLIFE SERVICE

finishes depositing her eggs. Males are no longer
attentive. The female is gaunt and spent, but
she continues to dig at the gravel with ever-
weakening efforts until she dies. This post-
spawning digging, which may continue for 10
days, becomes shallow, ofiF-center, and ineffective.
The area of the nest is increased without (after
the first day at least) adding to the protection of
the eggs.

In view of these facts, a mature redd is con-
sidered one in which all egg-laying activities have
been concluded, and some postspawning digging
has been accomplished.

Several criteria were used to determine whether
an observed redd was matiu-e: (1) The gaunt and
spent appearance of a lone female salmon still
digging — considered the most reliable criterion;
(2) the infrequency of the mating act, which
becomes sporadic as the supply of eggs is ex-
hausted; and (3) the presence of freshly covered
eggs in a redd unoccupied by salmon. Most of
the redds measured during the study met the first
criterion. For redds observed daily, the second
criterion indicated near maturity. Some blue-
back-salmon redds in which no fish were present
were considered mature on the basis of the third
criterion.

MEASUREMENTS AND METHODS

Size of the redds was determined by wading into
the stream and taking the length, depth, and
several width measurements. The outline of the
redd was sketched to scale on engineer's notebook
paper, with all pronounced irregularities drawn in.
Later, in the laboratory, a planimeter was used to
compute the area. The entire excavated portion
of the redd back to the tailspill's highest point was
included in the measurement. The prespawning-
digging area, usually located directly under the
crown of the tailspill, was thereby included. The
long tapering downstream slope of the tailspill was
not considered an essential part of the nest meas-
urement, for several reasons: Live eggs were rarely
found there; the velocity of the current would
carry fine sand and lighter silt considerable dis-
tances, resulting in elongation of the slope; and
often the downstream slope of the tailspill of one
redd would be disrupted by salmon making redds
immediately below it. Such tailspill encroachment

never proceeded far enough to endanger the eggs
laid in the neighboring redd.

Depth measm-ements were taken from the sur-
face of the water at 1-foot intervals starting at
stream bed at the upstream edge of the redd,
down the central axis, through the deepest portion,
and over the tailspill. A cross section at the
greatest depth of the redd was taken in similar
fashion from the stream bed on one side to the
stream bed on the other.

The gravel composition for each redd was
arrived at by estimating the amount of large,
medium, and small gravel that had been exposed.
The term "large" gravel is used to describe stones
more than 6 inches in diameter, but not necessarily
round. "Medium" applies to stones from 6 inches
down to 3 inches. "Small" applies to those less
than 3 inches, but larger than heavy sand.

Stream velocities were taken by clocking a bit
of drift over a measured course. The currents and
other flow conditions in a redd were determined
with an aqueous solution of potassium permanga-
nate.

The times of the salmons' first entry into the
streams, the times of first redd digging and of
peak of spawning, average stream and redd depths,
and water velocities and temperatures are shown
in the table.

Except in small, sparsely populated creeks, no
attempt was made to measure all the redds in a
stream. In rivers thickly covered with redds
throughout their length, only representative
sections were observed, but all the redds in Such
sections were measured, in order to avoid selection.
In these sections each redd was marked by driving
a stake at the downstream slope of the tailspill, or
by placing a number on a tree opposite the redd.
The stakes facilitated observation, from day to
day, of the redd-digging progress of an individual
salmon. Figure 4 is a diagram of a redd that was
marked on the first day of digging and measured
daily thereafter. In this diagram, it will be seen
that redd digging extended from September 20
to October 8. The sign of Venus (9) below the
line indicates the female, present each day the
redd was measured. The sign of Mars (cf) above
the line shows for each day the number of male
salmon actively attending and fighting for the
privilege of fertilization.

CHARACTERISTICS OF SPAWNING NESTS OF COLUMBIA RIVER SALMOX

101

Summary of information gathered on spawning of salmon in selected streams

CfflNOOK SALMON

SavRR

Chum

SALMON

Blueback salmon

Spring run

Summer run

Fall run

SALMON

In low-

in
Toutle
River
(1938)

er-Co-
lumbia

tribu-
taries 1

(1938)

White
River
(1939)

Little
We-
natchee
River
(1939)

We-

natchee
River

(1939)

Okan-
ogan
River

(1939)

Ohana-
pecosh
River
(1938)

Nason
Creek
(1939)

Entiat
River
(1939)

We-

natchee

River

(1939)

White
River
(1939)

Kalama
River
(1938)

Toutle
River
(1938)

Spawning schedule:

(■)
Aug. 20

(>)
Aug. 21

(>)
Sept. 7

(•)
Sept. 8

(>)
Sept. 23

Sept. 9
Sept. 20

(>)
Sept. 27

(')
(>)

(•)
(■)

(•)
Oct. 11

(')
Sept. 17

(»)
Oct. 2

(1)

First redd digging...

(S)

Peak of spawning

Aug. 28

Aug. 31

(')

Sept. 20

(')

Sept. 30

(')

Oct. 22

Nov. 22

Oct. 20

Oct. 12

Oct. 8

(1)

Spawning ended . ...

Sept. 10

Sept. 15

Nov. 15

Oct. 25

Oct. 15

(»)

Nov. 2

(')

(')

(>)

Nov. 4

Oct. 31

Nov. 15

Depth of stream: '

Average (mean)

._ .inches..

14

8.6

16

13

10

14

11.6

7.8

10

11.5

12

13

9

Minimum

do....

2

3

7

4

6

3

3

2

2

3

2

5

4

Maximum

do....

36

18

26

30

16

48

24

26

30

37

24

28

17

Depth of redds: •

Average (mean)

do....

9

8.5

10

9.7

9.3

10

10.7

8

8 5

5.5

5.7

4.2

5

Minimum

do....

3

4

4

4

5

2

4

3

3

3

3

2

2

Maximum

do....

20

14

19

18

14

17

18

20

17

9

n

8

9

Velocity of water:

Average (mean)

.cubic feet a second..

(>)

2

1.5

2

1.7

2

1.3

5''

(«)

1.6

1.7

1.8

1.7

Minimum

do....

(')

.5

1

1

1.4

1

1

(")

(■)

1

1

1.7

1.5

Maximum

do....

(')

3.5

2

3

2

3.5

3

(')

(')

1.8

1.9

2

2

Temperature (Fahrenheit) ot water:

Minimum

degrees..

51

47

40

55

47

52

42

42

40

44

48

54

47

Maximum

do....

53

52

55

62

51

61

58

S8

44

49

51

55

48

' Germany Creek, Abemethy Creek, Elokomin River, and Grays River.

' No data.

• Transplanted.

< Indefinite.

* Average measurements taken from surface to stream bed at each side
and at upstream, end of each redd.

• Depth below stream bed, taken at deepest part of redd.

/y<7/f ^«*/

^i&si^

Lono/'/'uc/ino/ tJec//

V — ioeo//on one/ compara^/ife a/ouft^on.e* or <
iJea/«

^ ^/«/

Figure 4. — Diagrammatic views of a fall chinook salmon redd measured daily.

102

FISHERY BULLETIN OF FISH AND WILDLIFE SERVICE

CHINOOK SALMON

The chinook salmon is native to the Pacific
coast from California to Alaska. Some runs ex-
tend from Bering Strait to the southern Siberian
coast. By transplantation of fertilized eggs, runs
have been established in the St. Lawrence River
and in certain parts of New Zealand. The
Columbia River supports the largest population of
the species.

In the Columbia River, most of the chinook
salmon migrate upstream from March through
September. The migration is divided into three
more or less distinct classes, and the fish are
referred to as spring-run, summer-run, and fall-run
chinooks, according to the time they leave the
ocean and start on their upstream journey. The
smaller spring chinooks, which average about 15
pounds in weight, ascend the Columbia River
system for considerable distances and spawn in
headwaters from mid-July to mid-September.
The larger summer chinooks do not go as far
upstream as the spring chinooks, and the time of
spawning is later, from September to mid-No-
vember. The fall chinooks spawn chiefly in the
lower Columbia River tributaries and in the main
stems of the Columbia and Snake Rivers at about
the same time as the summer chinooks, and the
two classes are comparable in size. The summer
chinooks have an average weight of about 30
pounds, and the fall chinooks average 20 to 25
pounds.

The following three sections describe and com-
pare the size and other characteristics of the
redds made by spring, summer, and fall chinook
salmon, in several tributaries of the Columbia
River.

SPRING CHINOOK

Investigation of spring chinook salmon redds
was made in the Ohanapecosh River, a tributary
of the Cowlitz River (which is a lower-Columbia
tributary), and in Nason Creek, a tributary of
the Wenatchee River. The Ohanapecosh has a
natural run of spring chinook salmon, whereas the
Nason was one of the streams into which fish were
transplanted during the Grand Coulee fish-
maintenance project.

The average redd size and gravel composition
of these two streams may be compared in figure 5o,
circles A and B. The Ohanapecosh, a mountain
stream, contained a high proportion of large

rubble about the size of a football. Because of the
large-gravel component, the Ohanapecosh redds
were considerably smaller (2.9 square yards) than
Nason Creek redds (4.9 square yards). The
Ohanapecosh redds contained an average of 59
percent medium and small gravel, whereas the
Nason Creek redds averaged 86 percent medium
and small.

Spawning times, stream depths at the redds,
depths of redds, and water velocities and tempera-
tures for the spring-chinook redds in the two
streams are given in the table.

SUMMER CHINOOK

The spawning of summer chinook salmon was
studied in the Entiat River, the Wenatchee River,
and the White River tributary of Wenatchee Lake.
These are streams selected as foster rivers for some
thousands of the chinook salmon blocked by Grand
Coulee Dam. The spawning redds measured were
made by the transplanted salmon, trapped at
Rock Island Dam near Wenatchee, Wash., in July,
August, September, and October. Because of the
similarity of summer-run to fall-run chinook sal-
mon in all but time of migration, I have combined
the measurements of the summer-chinook redds
with those of fall-chinook redds in the size fre-
quency graph, figure 7.

For the 41 redds measured in the Entiat, the
average size was 7.8 square yards. A comparison
of the Entiat average, figure 5a, circle C, with the
average nest areas for summer and fall chinooks
from other streams shows that the Entiat River
redds were distinctly larger than those in other
streams. The Entiat River contains an abundance
of medium and small rubble which facilitated redd
construction and resulted in large redds. The
degree of cementation was less in the Entiat than
in the Kalama River or the Toutle River (where
fall-chinook redds were studied) and probably con-
tributed to the ease of digging. Subsurface per-
colation was greater, and this is a factor that
governs the location of redds to a greater extent
than is generally recognized.

It was noted that most spawning took place on
gravel through which there was a flow of water.
The flow was detected by releasing potassium-
permanganate solution in test holes in the stream
beds. There were areas in the Entiat River and
in nearly all streams examined, apparently unex-
celled for redd building and where trial redds were

CHARACTERISTICS OF SPAWNING NESTS OF COLUMBIA RIVER SALMON

103

visible, that were deserted by salmon for no other
ascertainable reason than that there was little or
no flow of water through the gravel. Gravel
firmly cemented with silt and clay binders usually
lacked a percolating flow and was avoided by
Entiat River chinooks and by salmon in other
streams. All species showed a decided preference
for moderately bound stream-bed materials in
place of either loose shingle (free-rolling gravel) or
firmly bound rubble.

Nearly all spawning of summer chinook salmon
in the White River took place in areas of the stream
that contained 95 percent medium and small
gravel. As shown in figure 5a, circle D, 9 redds
were measured and the average nest area was 4.7
square yards. Although this appears to contradict
the inverse-ratio relation between gravel size and
redd area, it is not considered significant, in view
of the small number of redds measured. As its
name implies, the White River is clouded by quan-
tities of chalky glacial material during the summer
and fall run-off, and this made observations diffi-
cult.

The redds studied in the Entiat, Wenatchee, and
White Rivers were made by salmon transplanted
to each spawning area over a long period of time.
Relocation was spaced out in order to keep the
sexes evenly distributed in each area. As a result,
there was a mixture of stocks, or races, of summer
chinook on the same spawning areas, and a wide
assortment of sizes of redds resulted. Although the
summer chinook are a little larger, as a class, than
the fall chinook, their redds contained about the
same proportion of large, medium, and small
gravel as fall-chinook redds. Figure 5a, circle E,
shows that average redd size and gravel composi-
tion, for summer chinook in the Wenatchee River
are comparable to the redd sizes and gravel com-
positions for fall chinook in the Toutle River sys-
tem, figure 5o, circles G and H.

FALL CHINOOK

The Kalama River, the Toutle River, and the
Green River tributary of the Toutle, were selected
for study of fall chinook salmon redds. The
Toutle River is a tributary of the lower Columbia
through the Cowlitz River; the Cowlitz and the
Kalama enter the Columbia only a few miles
apart, about 60 miles from the sea. Thus, they
are neighboring streams and they have somewhat
similar watersheds — both are moderately forested

and have fair gradients — but here the resemblance
ends. Because of an insurmountable falls, the
Kalama River has only 7 miles of available spawn-
ing area, containing a high proportion of large
gravel. Most of the stream bed is of stratified
gravel, that is, stream-bed disturbances and sub-
sequent flooding have overlaid the large gravel
with successive layers of smaller stones. During
redd digging the salmon encountered the sub-
stratum of large rocks with the result that the
redds resemble oversize underwater Easter egg
baskets. The Kalama River fall-chinook redds
contained a higher proportion of large gravel
than did other fall-chinook redds. (See fig. 5a,
circle F.)

The Toutle River and its Green River tributary
are both accessible through virtually all their
lengths, presenting 40 miles or more of stream bed
with a greater choice of spawning rubble than is
available to the Kalama River fall chinooks.
The areas used contained gravel of relatively
uniform size with little or no stratification.
Whereas the Kalama River redds averaged 5.7
square yards with 41 percent large gravel, the
Toutle River redds averaged 6.5 square yards
with 11 percent large gravel.

It would appear, from examination of figure
5a, circles F, G, and H, and figure 6, that the
abundance of large gravel in the Kalama had the
effect of reducing the size of the fall-chinook redds
there as compared with fall-chinook redds in the
Toutle River and its Green River tributary.
The slightly smaller average for the size of the
Green River redds, figure 5a, circle G, may be
attributable to the fact that fewer redds were
measured; figure 6 shows that the modal size of
the Green River redds is greater than that of the
Kalama River redds. These differences might be
explained on the basis of the mechanics of redd
building: the large gravel in the Kalama was
difficult to dislodge and to move, so the resulting
redds were smaller, whereas the medium gravel of
the Toutle River was easier to dig in and produced
larger redds.

SILVER SALMON

Silver salmon are distributed throughout the
North Pacific from mid-California to Alaska and
in Asiatic waters as far south as Japan. The
greatest runs are found in the streams of Oregon,
Washington, British Columbia, and southeastern

104

FISHERY BULLETIN OF FISH AND WILDLIFE SERVICE

s5/>r/fT^ CA/ftooA

/Yason Cf.

4.9 ayt^a, 90 /-*Ma

0/?c

^h /?.

lonapeco^t

2.9 aye/sj 9^ f^Ms

Sufftftrar C/f/'/rooA

7.8 ayt/s, 4/ ree/efs

4:7 aye/j, 9 /••</</«
fa// Ch/nook

tc/enatcJtee A.
S. 9 Oy</s , 8S /'et/efa

Ko/ama /?. Creen /?. Toufle R.

S.7 aytA, /■^J r-eeA/j S.^ OyA , 2 7 /-ce^s 6.S aytA^ BS ^at/t/s

Figure 5o. — Average size and gravel composition of Columbia River salmon redds.

CHARACTERISTICS OF SPAWNING NESTS OF COLUMBIA RIVER SALMON

J- 1 Chum

//ver

105

7ou//e /?.

Loo/er Co/umoia Tribi.
Z.7 aye/jj 66 /-ee/t/s

S/uejback

2. uuds J J/ rec/i/s

/.8 ay*/i , 3/ redt/s

Okanoyan /i.

^arqe orave/ -mors //ton O <//a/t7.
/^ecZ/um and Sma// - 6 or /esi

Figure 56. — Average size and gravel composition of Columbia River salmon redds.

106

FISHERY BULLETIN OF FISH AND WILDLIFE SERVICE

Alaska. At maturity they average about 9K
pounds in weight and about 24 inches in length.

In the upper Toutle and Green River tribu-
taries of the Columbia, the silver salmon occupied
many of the same spawning areas as the fall
chinooks, and the two species were found spawn-
ing at the same time.

In general, the sUver salmon apparently prefered
small streams flowing only 3 or 4 cubic feet a
second and were present in a number of localities
not occupied by the chinook salmon. A compari-
son of the nesting habits of the two species was
obtained at a point where the Toutle River is
divided by a large bar into a broad and a narrow
channel. The small, 3-foot-wide watercourse was
populated exclusively by silver salmon. The
wider run, nearly 60 feet across, contained only
fall-chinook salmon. In the shallower upper
reaches of the Green River tributary, the two
species spawned virtually side by side.

The silver salmon demonstrated a redd-building
versatility that was not equalled by other species.
In the small Beaver Creek tributary of the Green
River, a stream of less than 2 cubic feet a second,
the bottom was composed of flat chunks of slate-
shale rubble that defied classification by the usual
gravel standards. The silvers were paired off
and spawning in stream-width redds that were end
to end for a distance of nearly 2 miles. In the
Toutle River, immediately below Spirit Lake,
silver-salmon redds assumed bizarre shapes, both
in surface outline and in bottom contour, as the
fish dug around embedded boulders and fallen
trees. This was the only salmon of the four
species whose redds contained up to 10 percent
mud. The gravel composition of silver-salmon
redds is shown in figure 56 and the size frequency
of the redds is shown in figure 7.

CHUM SALMON

Chum salmon are found in rivers of the Pacific
coast from Oregon to the Arctic Ocean and in
streams of the northern Japanese islands. In the
Columbia River these salmon spawn mainly in
the small tributaries only a short distance from
the sea. They average 26 inches in length and
weigh about 10 pounds at maturity.

The streams selected for a study of chum-
salmon spawning, Germany Creek, Abernethy
Creek, Elokomin River, and Grays River, are
tributaries of the lower Columbia River and only

a few miles apart. The chum salmon did not
migrate far upstream, and in Abernethy Creek
some spawned in tidal water so that the redds were
uncovered and dry at the surface during a part of
each day. Several of the redds were examined
when exposed, and live ova were found in the
damp gravel of the nest. At high water, these
redds were occupied by spawners, but it was not
determined whether they were the original
occupants.

Chum salmon were also found spawning in
water just deep enough to cover the lateral line of
the fish. When distm-bed they would dash out
of the water onto the banks and flop back into the
stream. In thickly populated sections, the redds
were ill-defined and overlapped from end to end
and laterally. The riffles contained hundreds of
opaque dead eggs and a few lives ones. Because
of the abundance of spawners and the overlapping
of nests, it was necessary to select redds for study
on the basis of their individuality of outline and
apparent maturity. These salmon were more
easily frightened than the other species so that it
was difficult to determine whether the females
were in continuous possession of their redds. In
a few instances it was definitely determined that
the same females occupied their nests for at least
3 days.

Of 66 chum-salmon redds measured, the average
size was 2.7 square yards (fig. 5b, circle J). The
proportions of large, medium, and small gravel
were similar to the proportions for most of the
other species. Chum salmon, even more than
other species, avoided firmly cemented gravel
bottom and spawned in sections of moderately
bound rubble where subgravel flow or percolation
was evident.

BLUEBACK SALMON

Blueback salmon is the name applied to the
species 0. nerka within the Columbia River System
and a few neighboring streams. In Puget Sound
and British Columbia they are called sockeye,
and in Alaska, red salmon. In the Columbia
River, blueback salmon average 3 pounds in
weight and 20 inches in length.

The blueback salmon differs from all the other
species in that the spawning redds, with few
exceptions, are made only in streams tributary
to lakes or along lake shores. The young salmon,
on emerging from the gravel of the nest, descend

CHARACTERISTICS OF SPAWNING NESTS OF COLUMBIA RIVER SALMON

107

without delay to the lake and live there at least a
year before migrating seaward.

Blueback-salmon redds are perfect models of
the nests made by larger salmon of other species.
The extent of the redd and the size of the gravel
chosen are scaled down to the size of the blueback.
The number of redds measured, the average size,
and the gravel composition are shown in figure
56, circles K, L, M, and N. The gravel composi-
tion was 90 percent or more of medium and small
size, with the small gravel (about the size of a
golf ball) predominating. The stream-tjrpe blue-
back redd contained a small pot of larger stones
to receive the eggs, had a loose tailspill, and was
oval. The lake-type redd in the shallows near
shore in Osoyoos Lake (Okanogan River water-
shed) was larger and of irregular shape; because
there was no current, the female would dig all
around the edge of the nest. As there were rela-
tively few of the lake-type redds, none were
measured.

REDD SIZE AND INTERREDD SPACE

In general, for all species of salmon the size of
the redds varies in direct proportion to the size
of the salmon comprising the run, and in inverse
proportion to the size and cementation of the
gravel in the stream. The redds made in slow
water are larger and more circular in outline, but
as a rule are not as deep as those made in rapid
water where the hydraulic force helps move the
gravel.

On crowded spawning gravels of riffles and
rapid runs, some chinook redds overlapped slightly
end-to-end because the long tailspill of one redd
would be disturbed by the female working
directly downstream from it. Only a few redds
overlapped laterally. As a matter of fact, few
redds of any species were made exactly side by
side, but occasionally the redds would form diag-
onal rows across the streams. For the most
part, the female chinook salmon was vigorously
averse to the presence of another female im-
mediately upstream from her nest, or one digging
directly at the side of her nest, until her own redd
was well under way.

The natural tendency of the female salmon
to guard the privacy of the redd area made for
fairly regular spacing. The more or less sym-
metrical oval shape of most nests was an addi-
tional space factor. The salmon redds in a

crowded stream area do not fit into each other
like the parts of a jigsaw puzzle, but have spaces
between them nearly as great as, or greater than,
the areas of the nests themselves. This interredd
space varies with the species and also with such
physical factors as population pressure, composi-
tion and gradient of stream bottom, and water
velocity. The ratio of interredd space to redd
size appeared to be less for chum salmon and
silver salmon than for the other species studied.
The contiguous and in some cases superimposed
construction of chum-salmon redds may have
been the result of overpopulation of the limited
spawning areas available in the streams examined.
Population pressure noticeably decreased the
interredd space of silver salmon in Beaver Creek
at the upper limit of spawning, where the stream
was wide enough for only one or two redds.

In the Kalama River, the large rubble made
for smaller redds, but interredd spacing was
about the same as elsewhere — presumably because
the nest radius to be defended remained the same
for chinook salmon of a given size. In quiet-water
areas, both redd size and interredd spacing were
proportionately greater than the redd size and
interredd spacing in stretches of rapid water
where the stream bed had considerable gradient.
In rapid water, the spawning salmon were busier
with redd digging, so that fewer "dog-fights"
occurred. Their distribution on the spawning
gravels was more or less uniform, resembling the
typical spawning-stream population of moderate
riffles.

In general it was noted for chinook salmon that,
wherever sufficient spawners were present to
utilize virtuaUy all the usable gravel, the interredd
space amounted to nearly three times the area
occupied by the redds. Thus, the total average
area necessary for a pair of spawning fish was
about four times the area of the average redd. For
other species, the space factor was somewhat less
than that for chinook salmon. It is believed,
however, that to arrive at a conservative figure
for the number of pairs of salmon that can satis-
factorily utilize a given area of gravel suitable
for spawning, the area should be divided by four
times the average size of the redds. Thus, a
pair of spawning summer or fall chinook salmon
would require approximately 24 square yards of
suitable gravel; spring chinook salmon, 16 square
yards; silver salmon, 14 square yards; chum

108

FISHERY BULLETIN OF FISH AND WILDLIFE SERVICE

IS

10

•^

WENATCHEE R.

autrttrtcf t^cfft

WHITE R. jummef /►«/>»

10

40

O

a 5
ui

E NT I AT R. summef /-t/f?

O
m
w

TOUTLE R.

Af// fc/^

GREEN R.

/i//

20

IS

10

KALAMA R.

2 3 4 S 6 7 8 9 10 II 12 13 14 IS 16 17 18 19 20

SIZE OF REDDS IN SQUARE YARDS

Figure 6. — Size frequency distribution of summer and fall chinook redds.

CHARACTERISTICS OF SPAWNING NESTS OF COLUMBIA RIVER SALMON

109

70

60

50

40

30

20

10

20

10

BLUEBACK

141 REDDS

CHUH

66 REDDS

(A

O

I

SILVER

65 REDDS

8 9

II 12 13 14 19 16 17 18 19 20

SIZE OF REDDS IN SQUARE YARDS
Figure 7. — Size frequency distribution of salmon redds from all streams combined.

no

FISHERY BULLETIN OF FISH AND WILDLIFE SERVICE

salmon, 11 square yards; and blueback salmon,
8 square yards.

SUMMARY

1. Observations were made on a large number
of chinook, silver, chum, and blueback salmon
redds in the Columbia River watershed, and 850
redds were measured.

2. Normally, the female salmon constructs the
redd, the male taking no part in this activity.

3. The redd is formed or excavated by the
female turning on her side and making violent
flexions of the body and tail. The boiling currents
set up by this action disturb the gravel of the
stream bed which is carried a short distance
downstream to form the tailspill.

4. A typical redd is an excavation in the stream
bottom, oval in shape, the greatest diameter being
lengthwise with the current, and with a tailspill
at the downstream end. The center of the redd
is referred to as the pot, and it is here that the
bulk of the eggs is deposited.

5. Current velocities at spawning areas varied
from less than 1 foot a second to 3.5 feet a second.
Redds made in fast water were invariably long
and narrow; those in quiet water had a broad
oval shape.

6. The current in the pot of the redd flows
slightly upstream, which favors safe deposition
of the eggs in the gravel and is conducive to
complete fertilization by the milt of the male
salmon.

7. As the spawning progresses, the redd in a
sense moves upstream by continued excavation of
the upstream edge and filling in of the tailspill

area.

8. In general, salmon chose areas of stream bed

composed of gravel less than 6 inches in greatest

diameter, with the size of the redd inversely pro-
portioned to the size of gravel. Firmly cemented
gravel was avoided, though where there was some
cementation, the size of the redd was inversely
proportioned to the amount of cementation.

9. Percolation of water through the gravel
appears to be a requisite of the redd site.

10. In general, salmon prefer areas of stream
bottom relatively free of mud or silt for redd-
making purposes. Silvers (0. kisutch) were the
only salmon of the four species which constructed
redds in areas of stream bottom containing up to
10 percent mud.

11. Average redd size for the various salmon is
as follows: Summer and fall chinook, 6.1 square
yards; spring chinook, 3.9 square yards; silver,
3.4 square yards; chum, 2.7 square yards, and
blueback, 2.1 square yards.

12. Few redds of any species were made side
by side. For the most part, nests were either up
or down stream from each other so that they
woidd form diagonal rows across the stream.

13. The tendency of female salmon to prevent
other females from getting too close resulted in
interredd space approximately three times the
size of the redd.

14. By dividing the area suitable for spawning
in a given stream by four times the average redd
area, a conservative estimate will be obtained of
the number of salmon that may satisfactorily
spawn in the stream.

LITERATURE CITED

Fish, Frederic F., and Mitchell G. Hanavan.

1948. A report upon the Grand Coulee fish-maintenance
project 1939-1947. U. S. Fish and Wildlife Service,
Special Sci. Rept. No. 55.

o

UNITED STATES DEPARTMENT OF THE INTERIOR, Oscar L. Chapman, Secretary
FISH AND WILDLIFE SERVICE, Albert M. Day, Director

CONTRIBUTIONS TO THE

BIOLOGY OF TUNAS FROM THE

WESTERN EQUATORIAL PACIFIC

By Bell M. Shimada

FISHERY BULLETIN 62

From Fishery Bulletin of the Fish and Wildlife Service

VOLUME 52

UNITED STATES GOVERNMENT PRINTING OFFICE • WASHINGTON : 1951

For sale by the Superintendent of Documents, U. S. Government Printing Ofifice, Washington 25, D. C. Price 15 cents

CONTENTS

Page

Collection of data 111

Notes on tuna spawning li;i

Yellowiin (Neothunnus macropierus) ^ 113

Big-eyed tuna (Parathunnus sibi) 114

Records of juvenile oceanic skipjack (Katsuwonus pelamis) 116

Occurrence of bluefin tuna ( Thunnus orienialis) 117

Siunmaiy 118

Literature cited 118

CONTRIBUTIONS TO THE BIOLOGY OF TUNAS FROM THE
WESTERN EQUATORIAL PACIFIC

By Bell M. Shimada, Fishery Research Biolosist

Kesearcli into the biolojiy of Pacific tunas has
advanced rajiidly in recent years, yet much re-
mains unknown about the life history and habits
of tuna species inhabiting waters of the former
Man(hited Islands now known as the Pacific Trust
Territories, in the western equatorial Pacific
Ocean. In prewar years, some scientific studies
were conducted by the Japanese, but these were
limited in scope and directed primarily towards
exploitation of the extensive tuna resources to be
found near their island possessions.

With the opening of the Trust Territories on
May 11, 1950, to Japanese mothership-type tuna-
fisliing operations, an opportunity was given the
Pacific Oceanic Fishery Investigations of the
United States Fish and AVildlife Service to gather
important data on tunas of this region by send-
ing a scientific and technical observer along with
the first mothership expedition to leave Japan.
I was subsequently detailed aboard the mother-
ship Tenyo Maru No. 2 and accompanied the expe-
dition from June 12 to September 14. 1950. Dur-
ing this assignment my principal duties were to
observe Japanese methods of fishing and process-
ing tuna, and to collect morphometric data on
various tuna species for use by the Pacific Oceanic
Fisliery Investigations in current studies on Pa-
cific tuna populations. Some information was
obtained also on other biological aspects of tunas.
These incidental observations on the spawning of
yellowfin and big-eyed tuna, on the occurrence of
juvenile oceanic skipjack, and on the capture of
adult bluefin tuna in the area covered by the expe-
dition are summarized in this report.

Tliese studies were made possible througii the
cooperation of the High Commissioner for the
Trust Territoi-ies of the Pacific Islands and the
Natural Resources Section, General Headquar-
ters, Supreme Commander for the Allied Powers.
The assistance rendered by various membcis of
the Japanese Fishery Agency and the Taiyo Fisli-
ing Co., Ltd., aboard the mothership is also
acknowledged.

953180°— 51

COLLECTION OF DATA

The expedition, consisting of a mothership and
25 iongline-fishing vessels, commenced its activi-
ties in the vicinity of 4°35' north latitude and
143°32' east longitude on June 17, 1950. As the
season progressed, the center of fishing gi-adually
shifted eastward at a rate of about 100 nautical
miles a week, the changes in position of the vessels
being dictated largely by the success of fishing in
any one area. The deployment of fishing vessels
in a north-and-south direction was bounded by 1°
and 9° north latitude, but in general fishing was
mostly between 1° and 5° north latitude, for it
was here that the best catches were made. Wlien
operations were terminated on September 5, 1950,
the mothership's position was 8° north latitude,
15r)°46' east longitude, whence it returned to
Japan. The easternmost limit reached by the
catcher boats was 160° east longitude. In all, the
expedition fished an area of approximately 305,-
000 square miles from wliich it took over 4,055
tons of tunas, spearfishes, sharks, and other fishes
(table 1).

Table 1. — Total catch, by species, of Japanese tuna mother-
ship expedition, J une-Se.ptember 1950

Species

Catch 1

YoUowfin tuiiLi {Neothunnus macropterus)

Pounds

4.574,358

699,014

65,378

3,430

6,968

1,760.389

48.182

1,229

Big-evod tuna (PaTafbimmts sihi) .

Bluefin tuna (TItunmi.s orienialis)

Skipjack iKatsntioiins peJnmis)

While marlin (Maknini nttiTlina)

Striped marlin (^t'lknirn milsukurii)

Sailfish • (Isfinptionis oritfttalis) _

28,160

13,656

895, 022

23,048

Swordflsh (Xiphiaa gladius)

Shark

Others i

Total

8.118,834

1 Statistics provided by the Japanese Fishery Agency and converted to
pounds using conversion factor of 8.27 lbs.=l kan,

- Includes short-nosed marlin (Tetraplurus breriroslris).

3 Includes barracuda (Sphyraena argeiUea), wahoo (Acanthocvbium solaTidri),
and doliihin {CoTuphaena liippurus).

A few tunas wex'e caught by pole and line at tiie
surface, but gear employed chiefly was the long-
line. This type of gear was developed to a great

111

112

FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE

20
10

__ JUNE

N = 70

1

—

I

,UJ

Jmli^

la

10

_ JU
N>

LY

186

Jy

U

dl

k

k ,

—

I
<n

•^ 60

u.

o

_ AU

N =

GUST

= 821

—

q:

UJ

00 60

s

—

1

—

40

■^

I

"

30

—

80

1

—

10

o

HUU

mi

Olu

dil

i

1

^1

60

60

70

140

ISO

160

80 90 too 110 120 130

TOTAL LENGTH IN CENTIMETERS

FroTTBE I. — Length frequencies (if yellowlin tuna measured aboard the ujothership Temjo Maru No. 2. June-August 1950.

extent by the Japanese and is highly effective for
fishing subsurface levels for tunas and otlier com-
mercially valuable fishes otherwise unavailable to
fishermen. Although variations in the construc-
tion of gear and minor differences in operating
technique existed among the manj' fishing vessels
of the expedition, the louglines were built and
handled essentially in the same manner by all ves-
sel'; A good description of Japanese longline

gear and fishing methods is given by Shapiro
^(1950).

The principal species of fish landed was the yel-
lowlin tuna {NeotJiunnus macropterus) w^hich
comprised more than 50 percent of the total catch
bj^ v\eight and ninnber. Yellowfin tuna, because
of their export value, were delivei'ed to the mother-
ship as whole fish for freezing, whereas other
species were usually gutted at sea. Those yellow-

TUNAS FROM WESTERN EQUATORIAL PACIFIC

113

fin not suitable for freezing in the round because
of size or condition were butchered for filleting.
Such fish were examined whenever possible for
sexual maturity and food habits.

The big-eyed tuna {Parathunnus sibi) appeai-ed
less frequently in the catches than yellowfin tuna
but ranked second in percentage composition of
tuna landings by weight and number. Approxi-
mately S50 tons of this species were received by
the mothership. Biological observations were
made on big-eyed tuna similar to those for the
yellowfin.

NOTES ON TUNA SPAWNING

Yellowfin (Neothunniis macropterus)

Previous studies on the gonads of yellowfin tuna
have been largely confined to smaller fish, less than
a meter in length, usually captured by surface-
trolling gear (Schaefer and Marr 1948a, Wade
1950a). Schaefer and Marr's work (1948a) on
the spawning of yellowfin tuna in Central Amer-
ican waters included large fish, but even so, repre-
sentative samples from catches made by bait boats
and purse seinere were composed predominately
of fish measuring less than a meter. It is ap-
parent, therefore, that fishing gear designed to
fish at or near the surface catches smaller and
younger fish than subsurface gear and for this
reason does not supply material that gives infor-
mation on the maturation of older fish.

The longline, on the other hand, captures larger
fish. This is evident from figure 1 which shows
the plotted length-frequency data for yellowtin
tuna taken randomly from longline catches during
the season. Length frequencies of fish of less than
80 cm. include not only those caught by longlines
but also fish taken at the surface by pole-and-line
gear.

Although the proportion of males was usxuiUy
greater than that of females among yellowfin tuna
examined, the sex ratio sometimes running as high
as 80 males to 20 females in samples drawn from
landed catches, no effort was made to analyze the
condition of male gonads for it is extremely diffi-
cult, if not impossible, to make a reliable estimate
of the state of maturity by gross examination.
Milt was found in the central lumen of practically
all testes examined, even in those which, fi'om all
appearances, woidd be classified either as spent or
as ripening.

Female yellowfin tuna occurred more frequently
among fish below 130 cm. in length than among the
larger size groups, but in no case was it observed
that the proportion of females exceeded that of
males.

Ovaries of the fish examined were found to be
inmiature, ripening, or in spent condition, by
Marr's criteria (Schaefer and Man*, 1948a) of
gonad classification. Since the yellowfin tuna
probably spawns several batches of eggs over an
extended period of time, as suggested by Schaefer
and Marr (1948a), the ovaries possibly do not im-
mediately become much reduced in size after
spawning. A long-extended spawning season,
with individuals spawning more than once, would
result in an ovary ripening over a long period.
For these reasons, it is difficult, as others have
found, to distinguish between spawning and
ripening ovaries. The tabulated results of gonad
observations, table 2, probably include both of
these categories under the classification of "ripen-
ing."

No ovaries that could be considered ripe or run-
ning ripe were found. The absence from catches
of individuals ready to spawn has been noted
wherever studies have been made on the spawning
habits of yellowfin tuna. Sdiaefer and Marr
(1948a) observed no running ripe females and hy-
pothesized that, as spawning approaches, the fish
either migrate beyond the range of the fisliery or
stop feeding. In the Philippine Islands, Wade
(1950a) found ripe yellowfin in the course of his
investigations but no spawning or spent individ-
uals. Apparently this phenomenon is not limited
to the yellowfin tuna, for it has been observed for
big-eyed tuna (Parathunnus sihi), as noted later,
and for oceanic skipjack {Katsuwonus pelamis)
(Hataietal. 1941),

During early August, yellowfin females with
spent ovaries started to appear among catches
made 150 to 200 miles east and northeast of
Kapingamarangi Island (1°05' N., 154°45' E.).
Some such ovaries, flabby in a^ipearance and dark
red in color, might also have been observed in late
July if a check had been made then of incoming
fish. Spent ovaries were observed up to the time
fishing operations ceased in September.

From these superficial observations of gonads,
it was conjectured that the yellowfin tuna to the
east of Kapingamarangi Island had spawned in

114

FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE

Table 2. — Sexual maturity of female yellowjin tuna caught
in the western equatorial Pacific, June-August 1950

Approximate locality

Date

Approxi-

of capture

Total

Sexual

mate date
of capture

length

maturity

examined

Latitude

Longitude

MiUi-

meters

June 25

June 22

3-20' N.

Hl'.IS' E.

1,269 1

Ripening.

Do

do

3''20' N.

141°53' E.

1,285

Do.

Do-

do

3°20' N.

141''53' E.

1,269

Do.

Do-

do

3°20' N.

141°53' E.

1,379

Do.

Do

do

3°20' N.

Nl'.W E.

1,416

Do.

Do

do

3°20' N.

141°53' E.

1,230

Do.

June 26

do

2">51' N.
2°2,5' N.

142°07' E.
143°27' E.

1,485
1,427

Do.

June 30

June 26

Do.

July 2

June 27

I°51' N.

14.'i°43' E.

1,294

Do.

July 6

July 2 -

2°06' N.

14.'i''46' E.

1,324

Do.

Do-

do

2°06' N.

145°46' E.

857

Immature (or
spent?)

Do

do

2°06' N.

145°46' E.

884

Do.

Do

do

2°n5' N.

142°10' E.

1,142

Ripening.

Do

do

2''05' N.

142°10' E.

1,413

Do.

Do

do

2<'05' N.
2'>05' N.

142°10' E.
142" 10' E.

1,189
1,144

Do.

Do

do

Do.

Do

do

2''05' N.
2"'n5' N.

142°10' E.
142° 10' E.

1.064
1,256

Do.

Do

do

Do.

Do

do

2°05' N.

142°10' E.

1,032

Do.

Do

do -

2°05' N.

142° 10' E.

1,120

Do.

Do

do

2°05' N.

142°10' E.

1,232

Do.

Do

do -

2°n5' N.

142°10' E.

1, 243

Do.

Julys

July 3-

rsT' N.

144°05' E.

1.189

Do.

Do

do

rsT' N.

144°n.')' E.

1,446

Do

Do -

do

r37' N.

144°05' E.

893

Do.

July 9- -

Julys

2'>12' N.

149°25' E.

1.418

Do.

Do

do

2''12' N.

149°25' E.

1.353

Do.

Do

do

2<'12' N.

149°25' E.

1.347

Do. .—

Do

do

2''12' N.

149°25' E.

1.257

Do

Do

do

2°12'N.
2n2' N.

149°2.r E.
149°2.V E.

1.181
638

Do.

Do

do

Immature.

Do

do

2'>12' N.

149°2.V E.

673

Do.

Do

do

1''49' N.

149°08' E.

1,367

Ripening

Do

do

1°49' N.
1°49' N.

149°n8' E.
149°08' E.

1.222
1,249

Do.

Do

do -

Do. .---

Do

do -

1''49' N.
1°49' N.

149°08' E.
149°08' E.

1.364
1.281

Do.

Do

do -

Do.

Do

do

1°49' N.
1049' N.
1°49' N.
4°25' N.

149°08' E.
149°n8' E.
149°08' E.
150°.58' E.

1.303
1.256
1.344
1.420

Do.

Do

do

Do.

Do

-.-. do

Bo.

July 13

July 9

Do.

Do

...do

4°25' N.
I°18' N.

160°58' E.
155°30' E.

1,408
1,428

Do.

Aug. 3

July 29

Do.

Do

do

I-IS' N.

165°30' E.

1,390

Do.

Do

do

1°18' N.

155°30' E.

1,154

Do.

Do

do

1°18' N.

155°30' E.

1,203

Do.

Do

do

1°18' N.

156°30' E.

1.3.50

Do.

Do

do

ri8' N.

155''.30' E.

1,279

Do.

Do

do

1°18' N.

155°30' E.

1,233

Spent.

Do

do

1°18' N.

155°30' E.

857

Immature (or
spent?).

Do

do

1°18' N.

156°3D' E.

881

Do.

Do

do

1°18' N.

15.'i°30' E.

1,212

Spent.

Do

do

1°18'N.

l.W°30' E.

1,471

Ripening.

Do

do

I^IS' N.

155°30' E.

1,316

Do.

Do-^..-

do

\°\»' N.

15.'i°.3fl' E.

1,312

Do.

Do

do

1°18' N.

155°30' E.

1.343

Do.

AUB. 4-_

July 31

1°10' N.

l.")7°29' E.

1.395

Do.

Do

do-

1°10' N.

157°29' E.

1,498

Do.

Do

do

rio' N.

I.'i7°29' E.

1,213

Do.

Do -

do

PlC N.

157°29' E.

1, 465

Spent.

Do

do

1°10' N.

157°29' E.

1,365

Do.

Do

do

1°10' N.

157°29' E.

1,307

Ripening.

Do

do

1°10' N.

167°29' E.

1,277

Do.

Aug. 20

Aug. 15---.

3°35' N.

1S6°4.5' E.

l.,302

Do.

Do

do

3''35' N.

155°46' E.

1, 275

Do.

Aug. 29

Aug. 26.-..

2°22' N.

156°34' E.

1,092

Spent.

Do

do

2'=22' N.

156°34' E.

1,250

Do.

Note.— Y. Yabuta of the Nankai Fisheries Experiment Station, Tokyo,
Japan, assisted in making part of these observations.

July with active spawning commencing in June
and extending into August. Further hypothe-
sizing that a common yellowfin population had
been fished during the season — and there appears
to be no evidence to the contrary — it does not seem
unreasonable to believe that spawning had oc-

curred coiiuidentally throughout the area fished.
The spawning season is most likely a long one and
may not necessarih' be limited to the summer
months, but the peak of spawning probably is at-
tained during that period.

Yellowfin tuna found elsewhere in the tropical
western Pacific Ocean are generally believed to
spawn most actively during the summer months.
Preliminaiy studies by biologists of the Pacific
Oceanic Fishery Investigations indicate that dur-
ing 1950 this species spawned in the vicinity of
the Hawaiian Islands from early June to Septem-
ber. Ill the eastern Pacific, however, the spawn-
ing season is considered to be during the late
winter and early spring months (Schaefer and
Marr 1948a). This variation in time of spawn-
ing may be connected to some extent with latitude,
or it may be a race-connected characteristic. Dif-
ferences in spawning times of different races of
the same species in the same or similar places have
been observed in other species of fish, such as the
Pacific surf smelt (Schaefer 1936) and European
herring (Lissner 1934).

Big-eyed tuna (Parathunnus sibi)

Since big-eyed tuna were usually eviscerated at
sea, as previously mentioned, I was not able to
examine many reproductive organs of this species.
No check was made of the maturity of male fish,
but some females that were brought in whole were
opened and examined throughout the fishing sea-
son from late June to early September. These
females possessed either ripening or ripe ovaries,
with a few having what could be considered ad-
vanced-ripe ovaries. No running-ripe or fully
spent ovaries were found. Ovaries classified as
ripening may have been in a spawning state, be-
cause the big-eyed tuna, like the yellowfin, prob-
ably spawns over an extended period with succes-
sive batches of eggs being ripened and extiTided.

Ovaries that appeared ripe were gi'eatly en-
larged, round in cross section, and light pink in
color. Those approacliing the running-ripe stage
had translucent ova whicli were ready to emerge
from the follicles. A sample of 1,000 eggs from
such an ovary removed from a 1,102-mm. female
showed a modal group of large eggs centering
around 1.06 mm. in diameter (fig. 2) . The largest
eggs measured approximately 1.22 mm. The eggs
probably increase a little more in size as water is
absorbed after emission into the sea.

TTJNAS FROM WESTERN EQUATORIAL PACIFIC

-r 1 r I

115

.10 .20 .30 .40 .50 .60 .70 .80 90 l£>0 1. 10 1.20

DIAMETER IN MILLIMETERS
PiGURK 2. — Frequency histogram of ova diameters for a sample of 1,000 Parathunnus siW eggs.

116

FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICK

From these observations of gonads it may be
inferred that the big-eyed tuna also spawns in the
area south of the Caroline Islands. Partial veri-
fication of the existence of spawning grounds in
these waters is furnished by Marukawa (Hatai
et al. 1941), who reported at a gathering of
Japanese scientists convened to discuss tuna and
skipjack spawning that "Juveniles of big-eyed
tuna measui'ing 4.2 to 4.3 inches were found inside
yellowfin tuna taken by longlines in the Tokobei
area (Tobi Island, 3° N., 131°31' E.) last year,
while I was in Palau, by a ship of the Fisheries
Experiment Station.'" No mention is made,
how6ver,'of the date of capture. Despite cai-eful
search, juveniles of big-eyed tuna were not found
in the many stomachs of yellowfin tuna and other
jjelagic fishes examined aboard the mothership.

Little is known of the spawning season of the
big-eyed tuna; observations, however, suggest
that it spawns from June to September, and pos-
sibly later. The possibility is not excluded that
spawning may be a year-round phenomenon.

RECORDS OF JUVENILE OCEANIC
SKIPJACK (KATSUWONUS PELAMIS)

While examining stomachs of fish landed
aboard the mothership, I recovered and preserved
in formalin seven juvenile scombroids later iden-
tified as oceanic skipjack, Katsuwonus -pelamis.
One specimen, measuring 130 mm. from the snout
to the end of the hypural plate, was found on
July 21, 1950, in the stomach of a black marlin
{Makaira masara) caught a few days previously
in the vicinity of 1°30' N., 154°08' E. Two addi-
tional juveniles of 132 mm. and 169 mm. were re-
covered on July 24, 1950, from a sailfish {Istio-
phoms orientalis) captured by longlines near
2°28' N., 155°01' E. The remaining four speci-
mens, measuring 81 nnn., 94 mm., 132 mm., and
148 mm., were found in stomachs of yellowfin
tuna {Neothunnus macroptemis) , the smaller two
on August 4, 1950, and the larger two on August
8, 1950. The earlier catches of yellowfin tuna
were made at approximately 1°10' N., 157°29' E.,
and the later catches at 1°14' N., 157°28' E. Re-
mains of fish up to 250 mm. in size and identified
by skeletal characteristics as oceanic skipjack
were found in tunas and other pelagic fish but
were not retained because of their poor condition.

All of the listed juveniles except the »i-iiii«i.
fish were X-rayed in the laboratories of the Pa-
cific Oceanic Fishery Investigations in Honolulu,
Hawaii. On negatives taken of these juvenile
scombroids the skeletal "trellis"' of Kishinouye
(1923) (="basketwork" of Godsil and Byers
(1944)) was faintly visible in every case and
placed these fish within Kishinouye's family
Katsuwonidae. The Katsuwonidae include two
genera : Euthynnus, which is composed of species
having either 37 or 39 vertebrae (Kishinouye 1923,
Schaefer and Marr 1948b), and Katsuvjonun,
which contains a single species characterized by
41 vertebrae (Kishinouye 1923). There is no
knowledge of an overlap in vertebral counts be-
tween genera. The total count of 41 vertebrae,
including the urostyle, therefore, specifically iden-
tified these juveniles as Katsuwonus pelamis
Linnaeus.

For further verification, the 81-mm. juvenile
was stained, using HoUister's method (1934).
There are 41 vertebrae present with 20 precaudal
and 21 caudal vertebrae. The lateral processes on
the precaudal vertebrae are well developed and
the inferior foramina form a "trellis" with the
haemal arches. The haemal canal is large, and
the first closed haemal arch is on the twelfth ver-
tebra. The gill-raker count for the first gill arch
on the left side, which is 15 for the upper arch
and 38 for the lower, falls within the range of
counts given for adults — 15 to 20 and 36 to 38,
respectively (Kishinouye 1923). Palatine teeth
are present ; vomerine teeth are absent. Vestigial
palatine teeth were observed on the 94-mm. speci-
men and were absent on the next larger juvenile
of 130 mm., so that palatine teeth disappear at
a length somewhere between these two.

The presence of juvenile oceanic skipjack in
stomachs of fish caught throughout the area fished
by vessels of the expedition points to the existence
of extensive spawning grounds in or adjacent to
these waters. The only previous published record
of juvenile skipjack from this general locality is
that of Inanami (1942). Since this reference is
not generally available, my translation of his paper
is given here in full :

When I went to Truk in June of this year, I was shown
siiecimens of small skipjack at the Nanko Fishei'ies Com-
pany. Of tlie two, one specimen measuring over 6 sun
(180 mm.) was unmistakably a skipjack juvenile; the
other, measuring 1.5 »un (45 mm.) in length, may have

TUNAS FROM WESTERN EQUATORIAL PACIFIC

117

been a juvenile skipjack,
ered for these specimens :

The following data were gath- Table 3.

-Bluefin tuna captured in the western equatorial
Pacific, June-September 1960

Date of capture

June 17.
June 26.
Julys,.
July 12.
July 14.
July 19.
July 26.
Aug. 10
Aug. 12
Sept. 4.

Locality of capture

Latitude

4°20' N.
4''30' N.
2°39' N.
4''0»' N.
3°48' N.
5°02' N.
2''25' N.
4°00' N.
4n5' N.
2°2S' N.

I/ODgitude

145''ao' E.
145°10' E.
148'>40' E.
147''57' E.
147<'55' E.
154-16' E.
155<'49' E.
157''30' E.
Mift'W E.
155''49' E.

(1) Dimensions: Length, 6.6 sun (198 mm.); weight

2r. mo«(»ie (94 grams). Fish No
Date of capture : 1700, April 23, 1939.

Place of capture : 4 nautical miles southwest of

Sarasbinm Pass (Salat Pass, 7'14' N., 152''01' E.). i

Method of capture : Pole fishing. 3"1!11II1III1I

At the same time, a specimen which could have been *

placed in a rice bowl and assumed to have been 6

about 3 snn (90 mm.) in length was caught but not gllilllllllllll

retained owing to the carelessness of a crew ';-

member.

(2) Dimensions: Length, 1.5 sun (4."i mm.); weight,

2moinme (8 grams). .species was caucfht this year indicates a possible

Date of capture: May 3, 1940. , • j- . ' • •., j- ^ -u x-

n, - . , , »■ , •, ^. ,.. , • change in tactors {loveniinsr its distribution or

Place of capture: 14 nautical miles oft Sarashima * . . . "^ g.

Pagg availabihty in the western equatorial region.

Method of capture : Recovered from the stomach of a Examination of available published logs covering

skipjack which apiiarentiy had been caught im- the prewar activities of Japanese tuna-fishing ves-

mediately after feeding, for there was no evidence gg]g j,^ ^^^ p^i.^^,^ Mariana, and Caroline Islands

failed to show bluefin tuna in their catches. With

It is said that small fish weighing 25 momme (94 grams) ^he exception of Abe's listing (1939) from the

are extremely rare around Truk, but that fish of this size t> , t i i j n,n . -i ,-i? i

„ ,, , n 1 1 • <- c „* r^alau Islands oi a 240-mm. specimen identined

are often seen around Palau during certain sea.sons of ^ ^ _ _

some years. ^^ Tfainmts thynnus{ = Thimmis onentcdis'i) , gis

Altliough oceanic skipjack are known to be
abundant in the vicinity of the many islands and
reefs of the western equatorial region, this species
apparently is not landbound, for several schools
were seen and fished far from land during the
operations of the expedition. Spawning prob-
ably takes place in the open ocean, as well as near
land, as inferred from the recovery of juveniles in
fresh condition from fish caught in deep offshore
waters. Judging from the sizes of young slcip-
jack found, some spawning must occur during the
spring months. Kishinouye (1924) estimates that
young skipjack grow at a rate of more than 40 mm.
a month. Calculations based on this growth rate
suggest that juveniles recovered aboard the moth-
ership in Julj' were spawned in March and April,
and those found later, in April, May, and June.

OCCURRENCE OF BLUEFIN TUNA
(THUNNUS ORIENTALIS)

The bluefin tunas are generally regarded as
temperate-zone foi-ms and are seldom found in
tropical waters. The capture of 10 large tunas
identified as bluefin or black tuna, probably Thwn-
?r(/.s- oHeiifalis (Temminck and Schlegel), l)y expe-
dition vessels is therefore of interest (table 3).
Furthermore, the frequency with which this

far as is known, no other distribution i-ecords exist
for bluefin tuna from this general area.

The captured fish were all large and weighed
from 150 to 500 pounds eviscerated and with gills
removed. Since these fish were cleaned at sea
immediately after capture and the viscera dis-
carded, it was not possible to examine the internal
organs and gill rakers. The pectoral fins of those
individuals examined were comparatively short,
and eacli fish was characterized by a dark over-all
coloration, which varied from black dorsally to
a dusky graj' veutrally. Measurements of dif-
ferent body characters, using standard morpho-
metric techniques described by Marr and Schaefer
(1949), were taken of four fish. The data are
presented in table 4.

There are three commonly recognized bluefin
species inhabiting the Pacific Ocean: the south-
ern bluefin tuna of Australia, Thimrvus maccoyi;
the Japanese bluefin or black tuna. Thunnus or'i-
entalis; and the so-called California bluefin tuna,
Thviimis thi/niiii,s. which is found in the eastern
Pacific and adjacent waters. The presently recog-
nized northernmost limit of distribution of T.
maccoyi is Sydney, Australia (Serventy 1941).
The Japanese bluefin tuna, T. oriodaJis, which has
yet to be proved distinct from T. thynnus, may
occur as far south as the equator, for there are

118

FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE

Table 4. — Measurevienls of four bluefin tuna from the western
equatorial Pacific

Fish No. 1

Fish No. 3

Fish No. 5

Fish No. 7

Date of capture

June 17

4''20' N.
145°20' E.

Julys

2''39' N.
148°4fl' E.

July 14

3'>48' N.
147''55' E.

487

2.239

631

661

1.185

1,373

748

675

July 26

Locality of capture:
Latitude

2°25' N.

I."i5°49' E.

Approximate weight
(less viscera and gills)

4.30

Total length mm . .

Head length mm-_

enout to insertion first
dorsal mm--

Snout to insertion second
dorsal .mm,-

Snout to insertion anal

mm -

Snout to Insertion ven-
tral mm..

Ventral insertion to
vent ' mm..

Greatest body depth

2.255
600

648

1.221

1.354

698

667

.578
418

441
391

48

2,139
582

624

1.136

1,253

649

632

550
406

344

331

46

2, 205
599

642

1,172

1,310

674

676

Length pectoral mm..

Length second dorsal

mm..

Length anal mm..

Diameter of iris mm..

406

423

428

61

389

377
365

45

I DeQned as the distance from a line connecting the insertions of the ventral
fins to the anterior edge of the vent.

records of this species from the southern Philip-
pine Ishmds as cited by Wade (1950b). How-
ever, Wade believed that the southern distribution
of T. orientalis was limited to the northern Philip-
pine Islands and that other records were of stray
fish.

The bluefin tuna herein recorded have been
assigned to T. (m-entalis on the basis of distribu-
tion alone. It may be shown in the future that T.
orientalis is either a valid species or is synonymous
with T. thynnus.

SUMMARY

Various biological investigations were con-
ducted aboard a Japanese tuna mothership on
tunas and other fishes landed by longline-fishing
vessels which operated in waters south of the Caro-
line I.slands during the summer of 1950. The re-
sults of these studies shed new light on the spawn-
ing and distribution of tuna species found in the
western equatorial Pacific.

Gonads of yellowfin tuna and big-eyed tuna were
examined for sexual maturity, and their condition
suggests the existence of spawning grounds for
these two species in or near the region fished. The
yellowfin probably spawns most actively during
the summer months. Observations of big-eyed
tuna lead to the conclusion that this species spawns

from June to September, and possibly during other
seasons of the year.

Several juvenile oceanic skipjack were recovered
from the stomachs of tunas and other pelagic
fishes. This is definite proof that oceanic skip-
jack spawn extensively in or near the area covered
by the expedition.

The occurrence of bluefin tuna in equatorial
waters is recorded on the basis of several fish
caught from June to September 1950.

LITERATURE CITED

Abe, Tokihaku.

1939. A list of the fishes of the Palao Islands. Palao
Trop. Biol. Sta. Studies, No. 4, pp. 523-583.
GoDsiL, Harey C, and Robeet D. Byebs.

1944. A systematic study of the Pacific tunas. Califor-
nia Div. Fish and Game, Fish Bull. 60, 131 pp., 18
tables, 76 flgs.
Hatai, Shinkishi, et aL

1941. A s.vmposium on the investigation of tuna and
skip.iack spawning grounds. South Sea Science
[Kagaliu Nanyo], vol. 4, No. 1, pp. 64^-75.

HoLI.ISTER, GlOKIA.

1934. Clearing and dyeing fish for bone study. Zoo-
logica, vol. 12, No. 10, pp. 89-101, figs. 18-21.

INANAMI, YOSHrrCTKI.

1942. Small skipjacli captured at Truk. South Sea
Fish. News [Nanyo Suisan Joho], vol. 6, No. 1,
p. 524.

KiSHINOUYE, KaMAKICHI.

1923. Contributions to the comparative study of the so-
called scombroid fishes. Jour. Coll. Agrie. Imp. Univ.,
Tokyo, vol. 8, No. 3, pp. 293-475, 26 figs., 22 pis.

1924. Observations on the skipjack fishing grounds.
Proc. Sei. Fish. Assn. [Suisan Gakkai Ho], vol. 4,
No. 2, ijp. 87-92.

LiSSNEE, H.

1934. On races of herring. Jour, du Couseil, vol. 9,
No. 3, pp. 346-364, 2 tables.
Mare, John ('., and Mit.Nint B. ScHAEFiat.

1949. Definitions of body dimensions used in describ-
ing tniias. U. S. Fish and Wildlife Service, Fishery
Bulletin 47, vol. 51, pp. 241-244, 1 flg.
SoHAEFKii, Milker B.

193(i. Contribution to the life history of the surf smelt,
Hyjioiiiesiis pretiosus, in Puget Sound. Washington
State Dept. Fish. Biol. Kept. 35B, 45 pp., 17 tables,
33 figs.
Schaefee. Milnee B., and John C. Mabb.

1948a. Contributions to the biology of the Pacific tunas.
U. S. Fish and Wildlife Service, Fishery Bulletin 44,
vol. 51, pp. 187-206. 5 tigs.

1948b. Juvenile Euthynnus Ihicatiis and Aiixis thazard
from the Pacific Ocean off Central America. Pacific
Science, vol. 2, No. 4, pp. 262-271, 4 flgs.

TUNAS FROM WESTERN EQUATORIAL PACIFIC

119

Sekventt, D. L.
1941. The Australian timas. Council Sci. and Indust.
Res. Australia. I'aniph. No. 104. 48 pp.. 1> figs., 4 pis.

Shapiro, Sidnet.
1950. Th<> .lapanese longline fislici-j for tunas. U. S.
Fish and Wildlife Service, Commercial Fisheries Re-
view, vol. 4, No. 2, pp. 1-26, 16 figs.

Wade, Chables B.

1950a. Observations on the .si)a\vning of Philippine
tuna. U. S. Fish and Wildlife Service, Fisliciy Uul-
letiu 55, vol. .51, pp. 4119-423, 9 tahles. 3 figs.

1950b. .Juvenile forms of Ncothunniin »iiii-roptcni.i, Knt-
smconits ptlamis, and EuthiiiinUH ijnito from Philip-
pine seas. D. S. Fish and Wildlife Service, Fishery
Bulletin 53, vol. 51, pp. 39.')-404, 13 figs.

o

UNITED STATES DEPARTMENT OF THE INTERIOR, Oscar L. Chapman, Secretary
FISH AND WILDLIFE SERVICE, Albert M. Day, Director

POSTLARVAL NEOTHUNNUS
MACROPTERUS, AUXIS THAZARD, AND

EUTHYNNUS LINEATUS FROM THE
PACIFIC COAST OF CENTRAL AMERICA

By Giles W. Mead
Illustrations by Walter B. Schwarz

FISHERY BULLETIN 63

From Fishery Bulletin of the Fish and Wildlife Service

VOLUME 52

UNITED STATES GOVERNMENT PRINTING OFFICE • WASHINGTON : 1951

For sale by the Superintendent of Documents, U. S. Government Printing Office, Washington 25, D. C.

Price 15 cents

CONTENTS

Page

Observations on adults 121

Observations on yofing 122

Key to postlarvae of five species of Central American scombrids 122

Neothunnus macropterus (Temminck and Schlegel) 123

Auxis thazard Lacep^de - 124

Euthynnus lineatus Kishinouye 126

Literature cited 126

m

POSTLARVAL NEOTHUNNUS MACROPTERUS, AUXIS THAZARD, AND
EUTHYNNUS LINEATUS FROM THE PACIFIC COAST OF CENTRAL
AMERICA

By Giles W. Mead, Fishery Research Biologist

UntU 1942, none of the spawning areas of the
several species of eastern Pacific tunas was laiown.
Since that year several such regions have been
identified and in each case the discovery has been
made by indirect means, through the collection
and identification of the pelagic postlarvae, for
the ripe eggs of the tuna have rarely been found.
Knowledge of the location and extent of the
spawning grounds of the tunas depends, therefore,
on being able to identify the young taken in
plankton collections. This paper provides a de-
scription of the identifying characters of the
juveniles of several tunas.

In the late spring of 1949 I had the opportunity
to make collections of pelagic postlarvae in waters
off the Pacific coast of Central America. Supple-
menting this material, a series of uncatalogued
specimens ' from the California Academy of
Sciences, which was collected off Central America
during the 1932 cruise of the Zaca, was examined.

OBSERVATIONS ON ADULTS

The fishes collected in the spring of 1949 were
taken from the motor vessel Alphecca, a tima
clipper fishing for the Westgate-Sun Harbor Co.
of San Diego, Calif. Actual fishing was confined
to the month of May in waters from 50 to 150
miles off the west coast of Nicaragua and El
Salvador. Diu-ing this period the 240-ton catch
consisted of j'ellowfin tuna, Neothunnus maeropter-
11^ (Temminck and Schlegel), and oceanic skip-
jack, Katsuwonus pelamis (Linnaeus), the former
comprising the bulk of the catch by weight and
number. Gonads of 25 of each species were
examined for degree of maturity. It was apparent
from this examination that the yello\vfin tuna
more than 75 centimeters long and all the oceanic
skipjack were in advanced stages of sexual ma-
turity. (Total lengths are taken from tip of snout

I Made available by Lillian Dempster of the California Academy of
Sciences.

963182-61

to distal end of the shortest caudal fin ray.)
Ovaries were swollen and turgid, although no ova
were visible to the imaided eye. Testes of both
yellowfin tuna and oceanic skipjack had milt in the
central duct. Several large male yellowfin were
running ripe, but no females in a similar condition
were observed in the catch. Two female black
skipjack, Evthynvus lineatus Kishinouye, 54.4 and
55.0 cm. m length were taken. Their ovaries were
similar in degree of maturity to those of the oceanic
skipjack. Two ripe female sierra mackerel, Scom-
heromorus sierra Jordan and Starks, were taken in
a bait haul at Alacapule, Mexico, in the Gulf of
Cahfornia. Eckles (1949) has described the post-
larvae of this species. Althougti numerous at-
tempts were made with a high-speed plankton net
to recover the eggs from the surface layers of
waters where mature fish were found, none proved
successful.

Apparently the spa\vning season for the tunas
is a long one and the spawning area large. Ehren-
baum (1924) outlines the probable spawning
grounds in the Mediterranean region and in the
Atlantic for the species represented in his collec-
tions by larvae and postlarvae. He also describes
the degree of maturity and possible migrational
routes of the adults. Similarly, various Japanese
workers have attempted to delimit spawning areas
in the western Pacific, and at present extensive
work is being done near the Hawaiian Islands and
the Phihppines. The spawaiing areas of the tunas
in Central America are now knowm to extend from
Panama north to Nicaragua and El Salvador and
off shore to a distance of more than 100 miles. It is
also probable that spawnmg of yellowfin tuna and
oceanic skipjack occiu-s off Mexico, since the Zaca
collections made there include frigate mackerel
and one larval black skipjack. It is not unlikely
that futiu-e work will show that this spawning
area extends throughout the tropical waters of
Central America.

121

122

FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE

OBSERVATIONS ON YOUNG

Since the tunas are subject to intensive fishing
in many parts of the world their biology has long
been under investigation. Kishinouye (1919)
outlines the early work done on the larval stages
of these fishes. As he points out in another
paper (1926), the work of Ehrenbaum (1924) is
probably the most important single work on the
young stages of these fishes. The fishes described
by Ehrenbaum (1924), Kishinouye (1926), Liitken
(1880) and other early workers were generally less
than 15 millimeters in length and were taken with
plankton nets. For the larger sizes the investi-
gator is dependent primarily on collections made
under lights or on specimens found in the stomachs
of adult fish. Such specimens as these have been
described by the more recent workers, Schaefer
and Marr (1948a, 1948b), Eckles (1949), Wade
(1949), and others. In this paper I shall describe
specimens principally between 10 mm. and 18 mm.
in length, larger than those taken in planlcton
hauls, and note characters I have fomid useful in
their identification.

As is generally the practice, the Alphecca often
drifted at night while on the fishing grounds,
offering an excellent opportunity for night col-
lecting. The collections were made imder a drop-
light suspended immediately above the water.
Fourteen such collections yielded, among others,
juveniles of the following three scombrid fishes:
Neothunnus macropterus, the yellou^fin tuna;
Euthynnus lineatus, the black skipjack; and Auxis
thazard, the frigate mackerel. Early stages of

Table 1. — Data on postlarval Auxis thazard, Neothunnus
macropterus, and Euthynnus lineatus taken from the
Pacific Ocean off Central America, May 1949

Location

Num-

Date

Species

berof
speci-

Length in

millimeters

Latitude

Longitude

mens

May 7....

11"'23'N.

90'=29..VW.

A. thazard

28

10. 5 to 28. 5

May 10...-

WSS-N.

89°66'W.

A. thazard

2

10. to 28.

E. lineatus

2

7. 6 to 10. 5

May 15... .

U°4fi'N.

87°28'W.

A. thazard

3

11.5 to 35.0

May 16....

11°46'N.

87°41'W.

A. thazard

2

27.0 to 30.0

May 17....

12°16'N.

89°31'W.

A. thazard

2

28. to 30.

N. macropterus.

2.1

IS. 5 to 25.

May 19....

ll''20'N.

87°20'W.

A. thazard

3fi

14. 5 to 31.0

E. lineatus

23

13. 5 to 18.

May 22...-

U''2f.'N.

89°22'W.

A. thazard

15

18.0 to 35.0

May24...-

10°47'N.

89°30'W.

A. thazard

57

13. 5 to 48.

May27..—

12'>50'N.

89-40' W.

A. thazard

1

19.0

E. lineatus

2

18. to 23. 6

May 28...-

11°05'N.

89'>55'W.

A. thazard

76

10. 6 to 48. 5

N.umcropterus-

12

10. 5 to 16.

May29---.

11°05'N.

SO-SS'W.

A. thazard

12

19. 5 to 36.

May 30..--

12''11'N.

go-is'w.

A. thazard

27

24. 5 to 40. 5

N. macropterus-

6

19. 5 to 26. 5

all these species have been described by Schaefer
and Marr (1948a, 1948b) from specimens taken
in the spring of 1947 off Central America. The
identification of their specimens made known
spawning grounds for the yellowfin tuna, oceanic
skipjack, black skipjack, and frigate mackerel off
Costa Rica and Panama. The present collec-
tions extend the known limits of these spawning
regions for three of these species 350 miles north-
west up the Central American coast. Dates,
positions, and other data for the collections are
reported in table 1.

KEY TO THE POSTLARVAE OF FIVE
SPECIES OF CENTRAL AMERICAN
SCOMBRIDS

A workable key for the identification of the
postlarvae of scombrids known to occiu- off
Central America is dependent on a few discrete
external characters. The teeth and body shapes
are similar in all species. Pigmentation, gill
rakers, preopercular spines, viscera, and, to some
extent, fin rays are in the process of development
and show variation within each species at a given
length. The characters used in the key presented
here were taken from specimens of Euthynnus
lineatus fi'om 7.5 mm. to 32.5 mm., Neothunnus
macropterus from 10.5 mm. to 26.5 mm., Scom-
beromorus sierra from 21 mm. to 71 mm., and
Auxis thazard from 10 mm. to 48.5 mm. in length.
The characters used separate species within these
ranges but may not hold true for larger or smaller
specimens. No specimens of Katsuwonus pelamis
were examined but the description of Schaefer
and Marr (1948b) based on two individuals, 21
mm. and 44 mm. in length, has been referred to
in preparation of the key. Thei'e is no spot on
the isthmus of the smaller of these two specimens.
The larger fish was cleared and stained for bone
study, thus destroying all pigmentation.

la. More than 17 spines in the first dorsal. Total number
of vertebrae more than 46, usually 47 or 48. First
dorsal pigmented distally. Pigment spot on point

of isthmus Scomberomoriis sierra.

lb. Less than 17 spines in first dorsal. Less than 46
vertebrae.
2a. First dorsal separated from the second by a distance
equal to or greater than half the length of the first
dorsal; usually 11 spines in first dorsal. Spot on
isthmus. Vertebral count usually 20+19=39
. x'iuxis thazard.

POST LAR\AL TUNA FROM CENTRAL AMERICA

123

Figure 1. — Ncolhunnus macropterus, 10.5 millimeters long.

2b. First dorsal continuous or almost continuous with

second dorsal.

3a. Pigment spot on point of isthmus. First

dorsal 14 to 16, heavily pigmented. Vertebral

count usually 20+ 17 •= 37 -Euthynnu^ lineatus.

3b. No pigment spot on isthmus.

4a. First dorsal 13 or 14, entire fin heavily
pigmented. Vertebral count 18+21'=39

Neoihiinnus macropterus.

4b. First dorsal 16, bearing a few moderately large
spots distally. Vertebral count 20 + 21=41
Katsuwonus pelamis.

NEOTHUNNUS MACROPTERUS (Temminck
and Schlegel)

A total of 42 specimens of this species was taken
in the collection, ranging from 10.5 mm. to 26.5
mm. in length. Representative specimens were
cleared with potassium hydroxide and stained
with alizarin (Hollister 1934) so that the bone
structure could be examined and the fin rays
counted. Fin- ray counts in very small specimens
are virtually impossible if the specimens are not
stained.

NeothunnxLs macropterus can be identified by its
characteristic shape, vertebral count (18 + 21),
and coloration, as described by Schaefer and Alarr
(1948b). No gill rakers can be seen in fish smaller
than 15 mm. The position and extent of the
visceral organs cannot be determined without
sectioning. Schaefer and Marr (1948b) note the
characteristics of the viscera and gill rakers in
specimens over 15 mm. With the exception of
the pectoral, the fins of a 10.5-mm. fisii have
within one or two rays of the complete complement
of spines or rays. The number of rays in the
pectoral fin increases from 13 in the 10.5 mm.

specimen to 30 in fish of 30 mm. Each half of the
upper and lower jaws bears 11 small, pointed,
irregularly spaced teeth. It was found that these
young yellowfin can be separated readily from the
other specie»s taken, without a special preparation,
by the absence of any pigmentation on the point
of the isthmus and by the heavily pigmented first
dorsal fin. In aU Euthynnus lineatus and Auxis
thazard examined there is a pigment spot on the
point of the isthmus overlying the junction of the
pectoral and pelvic girdles. No post larval Kats%
wonus pelamis were available for study, but
Milner B. Schaefer of the Pacific Oceanic Fishery
Investigations informs me that this spot is not
present on a 21-mm. specimen taken off Costa
Rica. I have found no reference to this spot in
the literatiu-e. This character is most useful for
separating very small A^. macropterus and E.
lineatus since both have a black dorsal fin and
they resemble each other closely in botly shape
until they attain a length greater than 15 mm.

Dermal pigmentation on a 10.5-mm. Neothunnus
macropterus is restricted to a thin strip along the
first dorsal fin insertion, a patch on the tip of the
snout and the heavily pigmented first dorsal fin.
Subcutaneous pigmentation occurs over the brain
and in the peritoneum overlying the dorsal third
of the viscera. In an 11-mm. specimen, the thin
strip along the first dorsal insertion extends
posteriorly to the base of the third ray of the
second dorsal fin; by the 12-mm. stage it lines the
upper margin of the body from the operculum to
the terminal rays of the second dorsal. Those two
specimens show a faint strip along the postcro-
ventral margin of the orbit. From this size up to

124

FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE

33 mm., the largest yellowfin examined, the color
pattern follows closely the description published
by Schaefer and Marr (1948b).

A 12-mm. yellowfin displays three prominent
spines at the angle of the preoperculum. Anterior
to these are thi'ee lesser spines, and thiee others
protrude from the preoperculum above the lai'ge
spines. With increasing length of fish, all spines
become more and more reduced in relation to the
size of the head. They are apparently overgrown
by the superficial layers of the preopercular bone.
In fish of 26 mm., the only spines discernible are
those at the angle of the preoperculum, and even
these are noticeably less evident. There appears
to be little, if any, growth in these spines over the
size range of the fish in my collections.

AUXIS THAZARD (Lacepede)

This species is the most numerous in the night
collections. Young stages are present in 12 of the
14 collections. The 157 specimens taken range
from 10 to 49 mm. in length. In addition to the
collections listed in table 1, two larger Auxis, 79
and 117 mm. fork length, were taken from the
stomach of a large yellowfin caught on May 6 at
11°40' N. latitude, 91°00' W. longitude. These

two fish, both broken and with the skin and fins
digested away, can be recognized as members of
the genus Auxis by the elongated right lobe of the
liver, the total vertebral count (39), and the struc-
ture of the individual vertebrae as described by
Kishinouye (1923: 460). The gill-raker counts,^
10-f- 1-1-32 and lO-f- 14-33, approximate the counts
made by Schaefer and Marr (1948a) on most of
their juveniles. In a recent paper. Wade (1949)
separates the Philippine species, Auxis (hazard
and A. tapeinosoma, on the basis of characters
among which only the gill-raker count is apphcable
to the young stages.^ He also points out, as
Schaefer and Marr (1948a) suggested, that there
are probably two species of Auxis in Central Amer-
ican waters. If we assume that there are two
species and that they can be separated by charac-
ters applicable to the Philippine species, my two
juveniles, as well as the postlarvae large enough to
show a definitive gill-raker count, are A. thazard.
The giU-raker counts of 10 specimens are given in

2 The method used in counting and recording gill rakers is the same as that
used by Wade (1949) in his discussion of the genus Auih.

3 Wade's description of Anns tapeinosoma agrees with that of Bleeker
(1854). However, the pattern and extent of the corselet scales in Bleeker's
figure (18M, pi. 7) of A. tapeinosoma agrees more closely with Wade's figure of
A. thazard.

Figure 2. — Aiais thazard, 11.5 millimeters long.

Figure 3. — Attxis thazard, 18 millimeters long.

POST LARVAL TUNA FROM CEXTRAL AMERICA

125

table 2. The most anterior arch on both right and
left sides was counted. Specimens No. 7 and No.
8 are apparently too small to have a complete set.

Table 2. — Oill-raker coui>ts ' of postlarval and juvenile
Auxis thazard

Specimen

Fork

length, in

millimeters

Right first arch

Left first arch

No. 1

34
34

41
38
42
35
26
30
79
117

9+1+30=40
8+1+30=39
8+1+31=40
9+1+31=41
9+1+32=42
7+1+30=38
5+1+22=28
7+1+28=36
10+1+32=43
10+1+33=44

8+1+30-39

No. 2

8+1+29-38

No. 3 -

8+1 +.30 -39

No. 4..-

7-i-l+32=40

No. 6

9+1+31-41

No. 6 -

6+1+2S-35

No. 7

4+1+22-27

No. 8

7+1+20-34

No. 9

10+1+33-44

No. 10

10+1+33=44

' The method used in counting and recording gill rakers is the same as that
used by Wade (1949) in his discussion of the genus Auxis.

The smallest Auxis in the collections is a dam-
aged 10-nim. specimen. Dermal pigmentation is
confined to narrow strips along the bases of the
second dorsal and anal fins and the dorsal and anal
finlets, along the lateral line from a point below
the posterior end of the second dorsal fin to the
posterior extent of the finlets, along the postero-
ventral margin of the orbit and to a small spot on
the point of the isthmus. The fins are usually
colorless although the first dorsal may bear a few
scattered melanophores. Four small spines occiu-
along the angle of the preoperculum. Each half
of the upper and lower jaws bears about 10 small
teeth. With increasing size of fish, the local centers
of pigmentation expand. On fish of 13 mm. the
dorsal strip of body pigmentation extends from the
operculum to the caudal at its point of least depth,
and a light coloration appears on the snout and
operculum. All areas in the dorsal hall" of the body

of fish larger than 20 mm. bear at least a light
covering of pigment spots. The degree of pig-
mentation varies greatly from specimen to speci-
men in this species. The pattern here described is
that found to be the most common.

EUTHYNNUS LINEATUS Kishinouye

This species is represented in the collections by
27 specimens, ranging from 7.5 imn. to 23.5 mm.
in length. Two fish were cleared and stained
and each was found to have a vertebral count of
37, the first caudal vertebra in each case being
the twenty-fii'st. As is the case with Neothunnus
macrophrus and Auxis thazard, the viscera of the
smallest specimens cannot be studied adequately
unless specimens are sectioned. Schaefer and
Marr (1948a, 1948b) describe the viscera in speci-
mens of Euthynnus lineatus more than 15 mm.
long. The first dorsal, point of the isthmus,
anterior half of the lower jaw, tip of the snout,
posteroventral margin of the orbit, and operculum
of the smallest specimen (7.5 mm.) bear scattered
melanophores. Subcutaneous pigmentation cov-
ers the brain and the dorsal margin of the peri-
toneum. The only dermal pigmentation evident
on the body of this specimen is a pau- of light
spots at the posterior end of the anal fin insertion.
At 10.5 mm. in length, light pigmentation appears
at the base of the first and second dorsals. Body
pigmentation is still confined to the bases of the
anal and the two dorsal fins. By 14 mm., the
pigment has spread anteriorly from the base of
the first dorsal to the area overlying the brain.
Coloration along the lateral line first appears m a
16-mm. specimen as a few faint spots. On this fish

Figure 4. — Eutlii/iniii.'! lineatus, 14 millimeters long.

126

FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE

the dorsal body pigmentation extends posteriorly
from the operculum to the end of the second
dorsal. In the region of the second dorsal these
spots form a faint line a half millimeter from the
dorsal margin of the body. Above this line,
along the insertion of the fin itself, is the horizontal
bar of dark pigment characteristic of smaller speci-
mens. By 17.5 mm., the lateral pigmentation
has extended as far back along the Ime of the
vertebral column as the posterior end of the second
dorsal and anal fins. Coloration along the anal
insertion is stUl restricted to the few patches
characteristic of the smallest E. lineatus. The
posterior half of the orbit is dark. Coloration
of snout, jaws, and operculum is more dense.
At 22 nam., coloration fii-st appears over the

terminal segments of the vertebral colmnn and
on the extreme base of the median caudal rays.
The dorsal half of the body is dark as far back as
the caudal peduncle.

Preopercular spines are longer and slenderer
than those of A'^. macropterus. The angle of the
preoperculum bears the three largest spines.
Above these is a pair of small spines; anterior to
them are three others. With increasuig length
of fish, all become overgTO^vn to a certain extent.
At 18 mm., the most dorsal and anterior spines
are no longer visible without the use of special
techniques. The remainder ai-e visible, although
less distinct, m the largest E. lineatus in the
collections.

Figure 5. — Euihynnus lineatus, 22 millimeters long.

LITERATURE CITED

Bleeker, Pieter.

1854. Fauna ichthyologicae japonicae species novae.
Natuurkundig Tijdschrift voor Nederlandsch-Indie
uitgegeven door de Naturkundige Vereenigining in
Netherlandsch-Indie, vol. 6, pp. 395-426.
1854-57. Nieuwe nalezingen op de ichthyologie van
Japan. Verhandelingen van het Bataviaasch
Genootschap van Kunsten en Wetenschap, vol.
26, pp. 1-132, 8 pis.
EcKLEs, Howard H.

1949. Observations on juvenile skipjack (Katsu-
wonus pelamis) from Hawaiian waters and sierra
mackerel {Scomberomorus sierra) from the Eastern
Pacific. U. S. Fish and Wildlife Service, Fish.
Bull., No. 48, vol. 51, pp. 245-250.
Ehrenbaum, E.

1924. Scombriformes. Rept. Danish Oceanog. Exped.
1908-1910 to the Mediterranean and Adjacent
Seas, vol. 2 (Biology), No. 8, A. 11, pp. 1-42.
HoLLisTER, Gloria.

1934. Clearing and dyeing fish for bone study.
Zoologica (N. Y.), vol. 12, No. 10, pp. 89-101.

KiSHlNOUYE, KaMAKICHI.

1919. The larval and juvenile stages of the Plecostei.
Suisan Gakkai Ho, vol. 3, no. 2. (U. S. Fish and
Wildlife Service, Pacific Oceanic Fishery Investi-
gations, Translation No. 20 by W. G. Van Campen;
hectographed.)

1923. Contributions to the comparative study of the
so-called scombroid fishes. Jour. Coll. Agric,
Tokyo Imp. Univ., vol. 8, No. 3, pp. 293-475, 22 pis.

1926. An outline of the studies of the Plecostei
(tuna and skipjack) in 1925. Suisan Gakkai Ho,
vol. 4, no. 3, 1 pi. (U. S. Fi.sh and Wildlife Service'
Pacific Oceanic Fishery Investigations, Transla-
tion No. 18 by W. G. Van Campen; hectographed.)

LDtken, Ch. Frederik.

1880. Spolia Atlantica. Bidrag til Kundskab om
Formforandringer hos Fiske under deres Vaext og
Udvikling, saerlight hos nogle af Atlanterhavets
H0js0fiske. Vidensk. Selsk.Skr.,5. Raekke, natur-
videnskabelig og mathemetisk Afd., vol. 12, No. 6,
pp. 413-613.

POST LARVAL TUNA FROM CENTRAL AMERICA

127

Meek, Seth E., and Hii.debrand, Samuel F.

1923. The marine fishes of Panama. Pub. Field
Mus. Nat. Hist., Zool. ser. 15, part 1, pp. 1-330,
24 pis.

SCHAEFER, MlLNER B., AND MaRR, JoHN C.

1948a. Juvenile Euthynnus lineatus and Auxis
thazard from the Pacific Ocean ofi' Central America.
Pacific Science, vol. 2, No. 4, pp. 262-271.

1948b. Spawning of yeUowfln tuna (Neolhunnus

macropterus) and skipjack (Katsvwoniis pelamis) in
the Pacific Ocean off Central America, with
description of juveniles. U. S. Fish and Wildlife
Service, Fish. BuU., No. 44, vol. 51, pp. 187-196.
Wade, Charles B.

1949. Notes on the Philippine frigate mackerels,
family Thunnidae, genus Auxis. V. S. Fish and
Wildlife Service, Fish. Bull., No. 46, vol. 51,
pp. 229-240.

o

UNITED STATES DEPARTMENT OF THE INTERIOR, Oscar L. Chapman, Secretary
FISH AND WILDLIFE SERVICE, Albert M. Day, Director

JUVENILE OCEANIC SKIPJACK

FROM THE

PHOENIX ISLANDS

By Bell M. Shimada

FISHERY BULLETIN 64

From Fishery Bulletin of the Fish and Wildlife Service

VOLUME 52

UNITED STATES GOVERNMENT PRINTING OFFICE • WASHINGTON : 1951

For sale by the Superintendent of Documents, U. S. Government Printing Office, Washington 25, D. C.

Price 10 cents

JUVENILE OCEANIC SKIPJACK FROM THE PHOENIX ISLANDS

By Bell M. Shimada, Fishery Research Biologist

Studies by various investigators have added
substantially to oiu- hitherto hinited knowledge of
the spawTiiag of oceanic skipjack {Katsuwonus
pelamis Linnaeus 1758) ui the Pacific Ocean.
From evidence based on the examination of
gonads or the capture of juveniles (see table),
spawning grounds have been indicated in waters
ofi' Central America (Schaefer and Marr 1948),
the Hawaiian Islands (Eckles 1949), the northern
Marshall Islands (Marr 1948), the Ti'uk Islands
(Inanami 1942), the Phihppine Islands (Wade
1950), and the northern Ryukyu Islands (Kish-
inouye 1923). The existence of additional spawn-
ing grounds near the PhoenLx Islands in the south
central Pacific is demonstrated by the captm-e of
juveniles incidental to biological, oceanographical,
and exploratory-fishing studies conducted in this
locality during the summer of 1950 by the Pacific
Oceanic Fishery Investigations of the U. S. Fish
and Wildlife Service, Honolulu, Hawaii.

During a regular hydrographic cruise of the
Pacific Oceanic Fishery Investigations research
vessel Hugh M. Smith, between Hawaii and the
Phoenix Islands, two juvenile scombroids were
collected on July 18, 1950, at 3°50.5' S. and
171°48.5' W. by collaborating scientist V. E.
Brock,' and subsequently identified as oceanic
skipjack, Katsuwonus pelamis. These young fish,
measiu-mg 35 mm. and 48 mm. m total length,-
were captui-ed by dipnet under a night light while
the vessel was adrift.

On August 5, 1950, a sister ship, Hem-y O'Mal-
ley, visited the Phoenix Islands for exploratory
fishing. Wliile night-light collectuig from this
vessel at a position approximately 400 yards ofi'
the west end of Hull Island (4°30' S., 172°11' W.),
K. Yee,' caught thi-ee additional specimens of
juvenile K. pelamis. Total lengths of these fish
were 20 mm., 22 mm., and 36 mm.

Director, Division of Fish and Game, Territory of Hawaii.

3 Defined as the distance from the tip of the snout to the tip of the shortest
median caudal ray.

s Fishery Methods and Eriuipment Specialist, Pacific Oceanic Fishery
Investigations, U. S. Fish and Wildlife Service.

953184—51

All five specimens exhibit body contours typical
of juvenile oceanic skipjack and possess a very
slightly pigmented first dorsal fin and a colorless
second dorsal fin, which are characteristic of young
fish of this species (Schaefer and Marr 1948, Wade
1950). The 48-mm. juvenile of the Smith col-
lection was stained with alizarin red S and found
to have a "trellis" and a total of 41 vertebrae,
m'ostyle included. The 20-nun. specimen of the
O'Malley collection was stained and cleared after
HoUister's (1934) method and was found to have
a vertebral count of 20-1-21. These characteristics
are definitive of Katsuwonus pelamis as shown by
Kishmouye (1923), Frade and de Buen (1932),
and Godsil and Byers (1944).

The 35-mm. specimen is colored with light-
brown pigmentation except for the belly, which is
colorless, and the head. Pigmentation is more
concentrated dorsally and along the sides of the
body where it outlines a narrow band along the
midline. Scattered melanophores on the peri-
toneum are visible tlnough the thin body wall and
extend caudally to the anus. The top of the
head forward of the nape is brown in color with
subcutaneous melanophores on the underlying
brain covering. The upper portion of the oper-
culum, the posterior and inferior orbit, as well
as the sides of the upper and lower jaw, are lightly
pigmented with brown. The membrane between
the first and second dorsal spme is irregularly
marked witli black spots from the Inise to tlie
distal ends of the spines; the membrane comiecting
the remaining dorsal spines is similarly marked
but only near the tips of the spines, the basal
half beuig colorless. The second dorsal is with-
out color. Black pigment spots are present along
the upper pectoral raj's and along the upper base
of the fin. Similar spots are present along the
insertion of the median fins and finlots.

The first dorsal fin is composed of 16 spines of
which the second is the longest. Fouileen rays
are present in the second dorsal fin. There are
8 dorsal fuilets and 7 anal finlets. An interradial

129

130

FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE

membrane is present in both series of finlets and
joins individual finlets at a point midway between
the insertion and the tip. The anal fin has 15
soft rays, the pectoral 27 rays, and the pelvic 6
rays. The tip of one large spme and outlines of
two additional spines are visible at the angle of
the preopercle.

The two smallest specimens, of 20 mm. and 22
mm., agree in general with the description pre-
viously given for oceanic skipjack of this size by
Schaefer and Marr (1948), but differ in a few
respects from the larger juveniles. Body colora-
tion is lighter dorsaUy, and pigmentation is more
intense on the peritoneimi. The snout appears to
be more sharply pomted, possibly because the

upper jaw noticeably overlaps the lower jaw.
Two conspicuous spines are present at the bend
of the preopercle^ and the tip of one additional
spine is visible on the inferior margm. Pigmen-
tation of the first dorsal fin is linuted to distal
ends of the fin membrane between the first and
seventh or eighth spine. This is also true of
larger specimens, but in the latter coloration ex-
tends to the base of the first few anterior spines
as well. The basal portion of the pectoral fin is
colorless, and the dorsal and anal finlets are
joined at the tips by interradial membranes.

The capture of these small juveniles is definite
evidence that oceanic skipjack spawn in the
Phoenix Islands area.

Published records oj juvenile oceanic skipjack (Katsuwonus pelamis Linnaeus) from the Pacific Ocean

Date of capture

August 1916.
July 1923---

Do

August 1923- _
Apr. 14, 1924.

May 16, 1924-
May 19, 1924.

Do

May 21, 1924-

Do

Do

May-June 1924.

Do

June 1924

Do.
Do.

Apr. 23, 1939.
May 3, 1940..
Jan. 28, 1947-

Mar. 29, 1947.
July 24, 1947.

Do

May 7, 1948-

July 13, 1948.
Sept. 3, 1948-

Locality

Ryukyu Islands (Oki-
nawa) .
Ryukyu Islands

do

do

Ryukvu Islands (29°47'

N-i29°25' E.)
Ryukvu Islands (28° 10'

"N-i29°15' E.)
Rvukvu Islands (29°51'

N-i29°52' E.)
do

Ryukvu Islands (29°47'

N-i29°25' E.)
do

.do.

Ryukvu Islands (28°31'
N-i29°, 131° E.)

do

Ryukyu Islands

.do-
.do-

Truk Islands

do

Costa Rica (9°22.5' N.-

85°47.5' W.)
Costa Rica (9° 10' N-

85°20' W.)
Marshall Islands (Bikini

Atoll).
do

Philippine Islands

(6°37.2' N-121°31' E.)
Hawaiian Islands (20°30'

N- 158° 45' W.)
Hawaiian Islands (19°33'

N-156°00' W.)

Size

Num-

of

ber

speci-

of

men

speci-

(mm.)

mens

210

1

105

1

125

1

210

1

26

1

58

1

60

1

80

1

63

1

83

1

85

1

3

2

4

3

120

1

153

1

100 to

3

140

198

1

45

1

21

1

44

1

45

1

50

1

13 to

6

27

113 to

6

118

183

1

How collected

Pole and line (?)

From skipjack or yellow-
fin tuna stomach.

do

do

From skipjack stomach.

From skipjack or yellow

fin tuna stomach.
do

do

do

do

do

Plankton net

do

From skipjack or yellow-
fin tuna stomach.

do

Dipnet

Pole-and-line fishing

From skipjack stomach.
Dipnet

do

Regurgitated by skip-
jack.

do

Dipnet

Regurgitated by skip-
jack.
From skipjack stomach-

Reference

Kishinouye (1923, p. 388).

Kishinouye (1924, pp. 88-
89).

Do.

Do.
Kishinouye (1926, p. 128).

Kishinouye (1924, pp. 88-
89).
Do.

Do.

Do.

Do.
. Do.
Kishinouye (1926, p. 128).'

Do.i
Kishinouye (1924, pp. 88-
89).

Do.
Kishinouye (1926, p. 128).

Inanami (1942, p. 524).

Do.'
Schaefer and Marr (1948,
p. 193).

Do.

Marr (1948, p. 202).

Do.
Wade (1950, p. 399).

Eckles (1949, p. 245).

Do.

' Identification reported as doubtful.

SKIPJACK FROM THE PHOENIX ISLANDS

131

LITEIL\TURE CITED

EcKLEs, Howard H.

1949. Observations on juvenile oceanic skipjack
(Katsuwonus pelaniis) from Hawaiian waters
and Sierra mackerel {Scomberomorus sierra)
from the eastern Pacific. U. S. Fish and Wild-
life Service, Fishery Bulletin No. 48, pp. 245-
250, 3 figs.

Fr.\de, Fkrn.^ndo, and Fernando de Buen.

1932. Poissons scomberiforraes (excepte la famille
Scombridae) . Clef de classification principale-
ment d'apres la morphologie interne. Comm.
Int. pour I'Expl. Sci. de la M6diterrande,
Rapp. et Proc. Verb,, vol. 7, annexe A, pp.
69-70.

GoDsiL, Harry C, and Robert D. Byers.

1944. A systematic study of the Pacific tunas. Calif.
Div. Fish and Game, Fish Bulletin 60, 131
pp., 18 tables, 76 figs.

HoLLisTER, Gloria.

1934. Clearing and dyeing fish for bone study. Zool-
ogica, vol. 12, Xo. 10, pp. 89-101, figs. 18-21.

InaNAMI, YOSHIYUKI.

1942. Small skipjack captured at Truk. South Sea
Fish. News [Nanyo Suisau Joho], vol. 6, No.
1, p. 524.

KiSHINOUYE, KaMAKICHI.

1923. Contributions to the comparative study of the
so-called scombroid fishes. Jour. Coll. Agric.
Imp. Univ., Tokyo, vol. 8, No. 3, pp. 293-475,
26 figs., 22 pis.

KiSHINOUYE, KaMAKICHI.

1924. Observations on the skipjack fishing grounds.

Proc. Sci. Fish. Assn. [Suisan Gakkai Ho],

vol. 4, No. 2, pp. 87-92.
1926. An outline of studies of the Plecostei (tuna and

skipjack) in 1925. Proc. Sci. Fish A.ssn.

[Suisan Gakkai Ho], vol. 4, No. 3, pp. 125-137,

Ipl.

Marr, John C.

1948. Observations on the spawning of oceanic skip-
jack (Katsuwonus pelamis) and yellowfin tuna
(Neolhunnus macropterus) in the northern
Marshall Islands. U. S. Fish and Wildlife
Service, Fishery Bulletin No. 44, pp. 201-206,
2 tables, 1 fig.

Schaefer, Milner B., and John C. Marr.

1948. Spawning of yellowfin tuna (Neothunnus ma-
cropterus) and skipjack [Katsuwonus pelamis)
in the Pacific Ocean off Central America, with
descriptions of juveniles. U. S. Fish and Wild-
life Service, Fishery Bulletin No. 44, pp. 187-
196, 5 figs.

Wade, Charles B.

1950. Juvenile forms of Neothunnus macropterus,
Katsuwonus pelamis and Euthynnus yaito from
Philippine seas. U. S. Fish and Wildlife
Service, Fishery Bulletin No. 53, pp. 395-404,
13 figs.

o

UNITED STATES DEPARTMENT OF THE INTERIOR, Oscar L. Chapman, Secretary
FISH AND WILDLIFE SERVICE, Albert M. Day, Director

ESTIMATION OF AGE AND GROWTH

OF YELLOWFIN TUNA (NEOTHUNNUS

MACROPTERUS) IN HAWAIIAN WATERS

BY SIZE FREQUENCIES

By Harvey L. Moore

FISHERY BULLETIN 65

From Fishery Bulletin of the Fish and Wildlife Service

VOLUME 52

UNITED STATES GOVERNMENT PRINTING OFFICE — WASHINGTON : 19 5 1

For sale by the Superintendent of Documents, U. S. Government Printing Office
Washington 25, D. C. — Price_,15 cents

CONTENTS

Page

Sources of data and methods of collection 134

Analysis of weight frequency data 135

Discussion 141

Conclusions 145

Literature cited 145

Appendix 146

II

ESTIMATION OF AGE AND GROWTH OF YELLOWFIN TUNA (NEOTHUN-
NUS MACROPTERUS) IN HAWAIIAN WATERS BY SIZE FREQUENCIES

By Harvey L. Moore, Fishery Research Biologist

With a commercially important species, such as
tlie yellowfin tuna (A'eothunnes macropterus Tem-
niinck and Schlcgel), knowledge of age and growth
is essential in both the management and develop-
ment of a fishery. To be able to assign ages and
to determine the rate of growth makes it possible
to determine the number and strength of the year
classes that comprise the fishable stock. A
fishery dependent on a few age groups or year
classes is greatly affected by the marked success
or failure of the brood produced in any one year.
The reduction or increase in numbers is strongly
evident in the total catch when that particular
year class enters the commercial fishery. If,
however, the fishery is composed of many age
groups, the success or failure of spawning in any
one year will have little effect on the total stock.
It is only when there are several consecutive years
of marked failure or success that any appreciable
differences in numbers are evident.

The vital statistics necessary for quantitative
study of fish populations are based on knowledge
of the age composition of the stock. It would be
difficult indeed to determine such statistics as
rates of increase, decrease, fishing, and natural
mortality without some knowledge of age and
growth. These vital statistics are fundamental in
the management of a fish stock.

The age and growth rate of tunas may also be of
value in the study of migrations, since it seems
logical to expect, in general, that short-lived, fast-
growing fish travel shorter distances than fish
which are long lived and slow growing.

Since Petersen's first application of the method
of size-frequency study to age and growth de-
termination of plaice (1922) many such studies of
different species have been made. Much im-
provement in the original method has been made,
and the application of mathematical formulae to
describe the growth of fishes has contributed much
toward its refinement.

Application of length- or weight-frequency
analysis to study of growth of tunas has been
limited. Kimura (1932) calculated growth curves
for bluefin (Thunnus orientalis) and yellowfin
(Neothunnus macropterus) from weight frequencies
of fish taken in Japanese waters from 1924 to 1931.
Although the data were collected over a long
period of time, those for yellowfin were based on a
few specimens if all data were included in the
graphs. An examination of the data, as presented,
shows that the values plotted in the graphs are
based on a few specimens of yellowfin.

Westman and Gilbert (1941) employed length-
frequency distributions in their study of the
Atlantic bluefin (Thunnus fhynnus). The ages of
bluefin as determined by this work were based
primarilj' on scale readings although the conclu-
sions were correlated with the results of the length
frequencies. Westman and Xeville (1942), in
another study of the Atlantic bluefin tuna, used
length frequencies of tuna samples from chum-
ming and trolling catches made during August and
September 1941. The results of this study were
also correlated with scale readings. Brock (1944)
applied the method of length frequencies in a
study of albacore (Oerino alalunga) taken in the
North Pacific and was able to demonstrate the
growth of size groups through the albacore season.
Partlo (1950) has produced weight-frequency dis-
tributions of albacore {ThunnuN alalunga) taken
in the waters of British Columbia during 1949.
Sampling was not sufficient to show changes in
length throughout the albacore season, but the
frequency distributions show the definite size
groups which make up the fishery. Okamoto
(1940) apphed Petersen's method to weight data
of skipjack (Katsuwonus vagans) taken in Japanese
waters. It was possible to follow definite modal
groups through 5 montlis of the fishing season.
The question whether modes represented age
groups or whether they represented different

133

134

FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE

strains of skipjack was raised. The conclusion
was in favor of age groups.

There has been httle study of age and growth
determination of Hawaiian tunas. Some measure-
ments of the skipjack {Katsuwonus pelamis) were
collected by Bonham (1946) in 1944 and 1945,
and length frequencies were plotted from these
data. Bonham suggested the possibility that
two successive year classes were present, but
recognized the limitations of his data and did not
attempt to assign ages. Brock (ms.) made a
rather detailed study of size frequencies of skip-
jack. He was able to identify modal groups in
the catches of successive years and to demon-
strate progression of the modes during the year,
whence he concludes they are year classes. No
previous studies have been made of the Hawaiian
yellowfin tuna.

SOURCES OF DATA AND METHODS OF
COLLECTION

The data for this study were obtained from two
different types of fishery, the long-line or flag-line
fishery, ami the pole or live-bait fishery. The
long-line fishery in Hawaii is carried on through-
out the year in most of the waters around the
main Hawaiian Islands. The catch from this
fishery is sold primarily to the fresh-fish markets
by auction. The live-bait fishei-y, on the other
hand, is more seasonal and the catch is primarily
for the cannery, although some of the fish are
sold on the fresh-fish market, especially when
the cannery is not operating during the slack
season.

The long-line fishery is conducted by means of
setlines made up of units of gear known as baskets.
The term "basket" is derived from woven bamboo
baskets in which the units of gear are stowed. A
vessel fishes a long-line composed of about 30
baskets, each of which is from 140 to 203 fathoms
in length and has 4 to 6 brancii lines with hooks.
When the baskets are fastened together and the
long-line is set, the hooks fish from 30 to 50
fathoms in depth (June 1950).

Long-lines are set in the early morning and are
fished only during the daylight hours. LTsually
a few tunas are taken each day, and the catches
may also contain several marlin, swordfish, and
sharks. Fish taken by this method are generally
large in comparison with those taken in the live-

bait fishery. Yellowfin tuna caught by this
method average about 140 pounds in weight, and
the big-eyed tuna {Parathunnus sibi) are heavier.
The total landings, by months, vary considerably
in both the numbers and the species of fish caught.
The yellowfin is the most abundant species taken
during the summer months, and the big-eyed tuna
dominates the winter catch. Albacore also are
caught on the long-lines during the winter months,
but the numbers are small in comparison with
either of the other two species. Although the
tunas are definitely seasonal in availability, some
fish of all three species usually are taken during
the entire year.

The second source of data was the live-bait
fishery. This fishery is seasonal; most of the
catch is taken during the summer months. The
fisheiy is dependent on small live fishes which are
used as chum to lure the tunas within reach of the
feather lures or live bait on hooks on the poles of
the fishermen. The fish caught by this method are
much smaller than those taken by the long-line
method; the largest weigh near 25 pounds. The
fact that no large fish are caught on the surface by
the pole or live-bait fishery and no small fish are
caught at depths fished by the long-line gear indi-
cates that there may be a possible vertical migra-
tion downward of yellowfin tuna during the early
years of life.

Although this fishery is primarily for the skip-
jack, mixed schools of skipjack and yellowfin or
skipjack and big-eyed tuna are sometimes found.
Approximately 12 to 15 catches from mixed schools
are landed at the cannery each season. It was
from schools such as these that tlie data on small
yellowfin were collected for this study. Schools
of tuna, whether a pure school of skipjack or
mixed with either yellowfin or big-eyed tuna,
tend to contain fishes with little range in size.
Brock (ms.) says of skipjack schools, "no indivi-
dual school of fish sampled contained fish differing
by more than 20 centimeters in length and usually
much less." Differences in sizes of fish from dif-
ferent schools, however, were as much as 50
centimeters.

Weight and length frequencies of the long-line
catch were taken from fish sold at auction by the
Kyodo Fishing Co., Ltd., Honolulu. The officials
of this company were kind enough to allow measur-
ing of the fish on the auction floor before the

AGE AND GROWTH OF YELLOWFIN TUNA

135

bidding had begun. As the fish are sohl indi-
vidually, it is necessary for the company to keep
accurate records of the weight of each fish sold.
AYeights as determined by the auction company
were taken from the auction records whi<'h were
available beginning vvith November 1947. Weights
of tunas caught by the live-bait fishery during 1949
were recorded by Fish and Wildlife Service
scientists at the cannery of Hawaiian Tuna
Packers, Ltd. This study includes only the data
of 1948 and 1949.

The data for the 2 years consist of 4,793 indi-
vidual weights of yellovvfin tuna ranging from 5
to 265 pountls. Of the total number of weights
taken, 124 are of small fish most of which were
representative of four mixed schools caught by
live-bait methods. A few of this group were taken
incidentally by trolling or hand-lining. The re-
mainder of the data were obtained from the auc-
tion records.

Since small yellowfin and big-eyed tuna are
likely to be confused, a check of the reliability of
species determination by the auction company was
made during October 1949. During this period
95 yellowfin and 272 big-eyed tuna were identi-
fied by various Fish and Wildlife Service scientists.
In no case was there found to be an auction record
in disagreement with our identifications. It was
concluded that the assignment of species as shown
by the auction records was accurate.

The auction records provided an excellent source
of weight-frequency data for several reasons. Be-
cause Honolulu is the center of population in the
Hawaiian Islands, most of the long-line catch is
landed there, and most of this long-line catch
passes through the auction of the Kyodo Fishing
Co., which supplied the auction records. Fish
taken by long-line gear are generally few in num-
ber per day's fishing, which would suggest that
either the fish tend to be solitary in habit or, if
they are schooled, only a few fish from several to
many schools are caught during a fishing trip.
Since tunas tend to school by size (Brock, in un-
published ms.; Schaefer 1948), samples of this
sort which are composed of a few fish from each
of many schools will tend to be more nearly
representative than large samples drawn from
only a few schools as are the samples from the
cannery.

Weights of fish in the round, that is, the entire

uncleaned fish as landed at the dock, were weighed
on the auction company's scales or on those of the
Hawaiian Tuna Packers. Weights were recorded
to the nearest pound for long-line fish and to the
nearest quarter pound for small fish taken by
live-bait fishing.

ANALYSIS OF WEIGHT FREQUENCY DATA

The initial step in processing the raw data (see
the appendix) was to plot the weights of individual
fish as frequency distributions for monthly
periods. A class interval of 10 pounds was arbi-
trarily chosen, with midpoint values of 4.5, 14.5,
and so on. Because the monthly catches varied
considerably in numbers of fish, they were made
comparable by converting the class frequencies
into percentages of the total for the month. The
average frequency distribution for each year was
calculated by averaging the 12 monthly -percentage
curves. The results are plotted in figures 1 and
2 for 1948 and 1949. In order to show more
clearly the presence of modes, positive de^nations
from the mean curve for the year are shaded on
the graph for each month. The scale at the
bottom of each graph is in terms of both weight
in pounds and length in centimeters. The length
scale was derived from the equation log L=
1.45660 + 0.33290 log IF which was calculated from
a sample of 200 length-weight measurements of
yellowfin tmia collected during 1949 by Fish and
Wildlife Service scientists.

Because there were many irregularities evident
in the frequency curves of each month's catch in
both 1948 and 1949, and because the 2 years were
similar in monthly frequency distributions, it was
convenient to combine the 1948 and 1949 data.
The combination of the data for the 2 years was
then treated in the same manner as that of the
the individual years with the exception of a process
of first smoothing the data by the formula

-7 1 where a, b, and c, are actual values for

consecutive class intervals. After smoothing, the
data were transformed into percentages of montlily
catch. The resulting monthly distribution curves
of the combined data with the superimposed
mean-percentage curve for the 2 yeai-s calculated
in the same manner as for individual years is
shown in figure 3.

136

SEPTEMBER

FISHERY BULLETIN OF

I I I I l .,l I I J I I I I I II

THE FISH AND WILDLIFE SERVICE

LENGTH IN
CENTIMETERS

FiGt'RE 1. — Weight-freqiK'iicy (iistributions (in percentage)
of long-line catches of yellowfin tuna landed at Honolulu,
1948. Monthly frequency distributions are shown by
fine line, and mean monthly frequency distributions by
heavy line. Positive deviations from the mean are
shaded.

FEBRUARY

AUGUST 5

SEPTEMBER 5

OCTOBER 5

ooooooooot^oooooooogjoooooo

I'll I I — 1 1 1 1 1—

Figure 2. — Weight-frequency distributions (in percentage)
of long- line catches of yellowfin tuna landed at Honolulu,
1949. Monthly frequency distributions are shown by
fine line, and mean monthly frequency distributions by
heavy line. Positive deviations from the mean are
shaded.

AGE AND r.ROWTH OF YELLOWFIX TUNA

137

Figure 3. — Weight-frequency distributions (in pereentagej
of long-line anrl live-bait catches of yellowfin tuna
landed at Honolulu. Smoothed data of 1948 and 1949.
Monthly frequenc}' distributions are shown by fine line,
and mean monthly frequency distributions by heavy
line. Po.sitive deviations from the mean are shaded.

Initial examination of the plotted data in
figures 1 and 2 shows the presence of a modal
group of fishes which can be followed through most
months of both 1948 and 1949. The group was
designated .V for reference. In the 1948 data the
progression of the modes representing this group
indicates gradual growth until June, followed by
a 5-month period in which no growth is indicated.
Following this there appears to be a short period

of rapid growth from October through December.
From January through December, modal group A^
shows a gain in weight from 75 to i;}5 pounds, a
gain of 60 pounds in 1 year. Also present in the
plotted data is a smaller size group which becomes
evident in the long-line fishery in October 1948
and in December 1 949. This suggests the entrance
of a modal group 1 year younger than group A'^.

The 1949 data (fig. 2) presented a similar trend
in modal progression, except for the last 3 months
of the year where rather erratic modal peaks were
evident. Because the catches for these months
were not large in comparison to catches of the
summer months (table 1) any unusual distribu-
tions of weights of fish landed would cause erratic
modal peaks to appear in the percentage frequency
distributions.

Table 1. — Xumbers of yellowfin liina taken by long-line
fishing and auctioned at the Kyodo Fishing Company,
Ltd., Honolulu, in 1948 and 1949

Month

January

February...

March

April

May

June

July

August

September.

October

November.
December..

Total

1948

2,488

1»49

40

39

fil

73

45

20

60

67

97

158

3fi2

514

530

M5

M2

400

381

165

179

102

99

31

92

67

2,181

For a more detailed study of the combined data
of the 2 years, a criterion was set up to determine
what should be designated a mode and to designate
its position. . Modal peaks of positive deviations,
evident in the combined 2-ycar data, when plotted
as deviations from the mean curve (fig. 4) which
met either of the two following conditions were
treated as modes in this study:

(1) Any positive deviation of a class which
shows a difference of 0.5 or more from values of
both adjacent classes (fig. 5-A).

(2) Wlum the difl'erence between frequency
values of positive deviations of two adjacent
classes is less than 0.5, and when the frequency
values of the classes above and below these two
adjacent values are at least 0.5 less than the
adjacent values, the intersection of the extrapola-
tion of the lines connecting the two classes with
the adjacent classes was considered the position
of the mode (fig. 5-B).

138

FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE

This was done by the "transformation" method
of Walford (1946). This is a graphic method of
describing the growth of animals above the point
of inflection, the self-inliibiting phase of growth.

5.0

150 160 170 180
A

190 200

Figure 4. — Deviations of monthly frequency distribution
from the mean monthly frequency distribution (in per-
centage) for combined and smoothed 1948 and 1949 data. 4,0

Using the above criterion, values of modes were
selected as shown in figure 6. Each mode has
been labeled with the age group to which it was
presumed to belong. In order to plot modal
positions against successive months, January of
group A'^ was arbitrarily assumed to occur in
month 37. Thus the mode of group .A^ in Feb-
ruary, March, April, and so on, was plotted in
figure 5 against 38, 39, 40, and so on. Modes
corresponding to groups which are presumed to be
a year younger or older were then plotted 12
months above or below the month value corre-
sponding to group A'^.

Assuming group A'^— I to be 1 year younger than
A'^ and group 7V+I to be 1 year older, A^+II 2
years older, and so on, we proceeded to determine
whether a regular growth curve fitted the data.

200

B

FiGllRB

5.— Theoretical conditions demonstrating the
criterion used in selection of modes.

AGE AND GROWTH OF YELLOWFIN TUNA

139

Size of fisli in fi^curc (i was plotted in tcfnis of
l('i\<rlli nitlicr than wi'i^'-ht since tliis method of
filtin<x a fiiowth cui've is applicable to sizes above
the inflection point. It was obvious from a plot
in terms of wei<rhts ((i>r. 9) that the inflection
I)oint is within the ranfje of our data, whereas our
data in terms of length appear to be above the
inflection point.

P'or the growth of a number of species of animals,
Walford's graphic transformation method gives a
straight line when the lengths at age 1, 2, H, 4,
. . . 7i, reiiresented on the a: axis, are plotteil
against the lengths at age 2, :i, 4, 5, . . . n+1,
on the ?/ axis. This method assumes the growth
during each period to be of constant ratio to that
of the previous period. It has already been noted
that the modes make all their progress during half
the year and none in the remainder. This should
and does show as a stepwise or sinuous deviation
from the straight line. Also, this method requires
length values for each consecutive unit of time, in
this case for each month. Within the limits of
our data (fig. 6) there w-ere 28 months for which no
modal values were evident in the plotted data.
To furnish estimates of the missing values, linear
interpolations were made between observed
monthly values.

200

ISO

The series of actual values and interpolated
values was then smoothed twice by a running
average of three and resulting values of length at
age I) were [)lotted agairLst lengths at age n+1
where age is in months. The plotted data are
well fitted by the least-squares line }'=7.04 —
0.96.336 A^, where )' is length at age n + l, and X
is length at age /( (fig. 7). From this straight line
the upper limit of growth or the upper as\^mptote
can be derived according to Walford's method by
taking the point of intersection of the line fitted
to the plotted data and the line of no growth
represented by a line of slope 45° through the
zero point (fig. 7). In the case of the yellowfin tuna
data used herein, the value in length at the point
of intersection of the two lines is at 190.0 centi-
meters, which in terms of weight is equal to 294.9
pounds. A maximum weight of this magnitude
is within reason for this species; several specimens
approaching this limit have been taken in the local
flag-line fishery. The largest specimens included
in this study, however, were between 260 and 269
pounds.

Because the plot of n against '(+ 1 is a constant-
percentage rate' and not actual-length values, it is
possible to choose the point through which the
curve should be passed. As the period from

X

100

50

1 1

1

1

•

-1 o
o

3

«
•
••

1

1

•oo«

1

N +n
,00000000 •

N-

N -I

1

I

c

• •

o
o

•

1

1

1

1

1

1

10

15

20

25

30

35

40

45

50

55

60

65

70

MONTHS

FiGCRK 0. — Actual aiifi interpolated values in Iciintli plollcd against iiiontlis and sliowinn assisuod modal groups. Solid
points arc actual values and circles arc interpolated values. F'Votu coinhiricd and sniootlied 1948 and 1919 data.

953183 O - 51 - 2

140

FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE

-r

ZOO

LENGTH IN CMS AT AGE N

Figure 7. — Combined 1948 and 1949 length data are plotted by the method of VValford (1946) and fitted with a straight
line. The intersect of the straight line and the line at 45° through the zero point indicates the upper asymptote
of the yellowfin tuna. Points mariied by O are observed vahies.

month 37 through month 47 is the time group N
and is most evident in the plotted data, the mean
month and mean length of fish occurring in this
period were used as the initial point for computing
the relation between fish length and time.

The reconstructed growth curve of length on
time and the plotted values of the original modes
are shown in figure 8. Since figures 7 and 8
indicate that the position of plotted mode values
are well fitted oy the calculated growth curve,
this serves as verification of the assumption
that modal group N—1 is a year younger than

N, group N+I is a year older than N, and so on,
is correct. Since the original data were in terms
of weight, the calculated curve was also trans-
formed back to those terms. The growth curve
of weight on time is shown in figure 9.

From the results of figures 8 and 9, it is possible
to determine approximate age of fishes. Ex-
trapolation of the curves downward suggests the
origin of the fish to be in year A'^— III. Ex-
amination of the gonads of yellowfin taken in
local waters indicates the spawning period to be
centered about the summer months. Assuming

AGE AND GROWTH OF YELLOWFIN TUNA

141

tills to be true, the month of June may be selected
to represent the mean spawning period; thus,
the period from Juno A'— III to June A"— II
represents age group 0, or fish in their first year
of life, June A^— II to June N — I, age group I,
and so on. Owing to possible error in extrapolat-
ing the curves downward to the origin, the ages
thus assigned may not be quite correct. It is
felt, however, that ages through group IV cannot
be more than 1 year in error.

Sella (1929) states that bluefin tuna hatched in
June weigh 300 to 500 grams by September. This
is a weight of approximately 1 pound and would
fall very close to our growth curve as calculated.
Kishinouye (1923) says of the common tunny
{Thunnus orientalis), "such small individuals are
found in August and in September. Some of them
grow to a length of 30 cm. or more. By next spring
they grow to a length of ca 60 cm. When 2 years
old they are about 1 meter in length and 1 1 kg.
in weight." These values when plotted on our
curve are not much in disagreement. Specimens
of yellowfin tuna have been taken during the
month of December in Hawaiian waters weighing

2 pounds; these weights when plotted, also fail
very close to the curve of figure 9. Lengths and
weights by age groups may also be assigned from
figures 8 and 9 as has been done in table 2.

Table 2. — Lengths and weights hy age groups of yellowfin
tuna taken in Hawaiian waters determined hy the method
of growth analysis of Walford (1946)

.\ge group

Length in centimeters

Weight in pounds

I

54-103 .. ..

7-46.

II

103-136

46-108.

Ill

136-155 -..-

108-163.

IV

155-168

163-208.

DISCUSSION

In fairly close agreement with this study are the
observations of Schacfer (1948) of the yellowfin in
the waters off Central America, where modes in
length-frequency distributions were observed at
approximately 60 cm., 85 cm., and 115 cm. These
modes, when plotted against the assumed age and
the month at which the fish were taken, showed a
close similarity to the age-length curve of the
Hawaiian yellowfin (fig. 10). The conclusion of

AGE GROUP

200

150

X

o

-J

100

L_„

5 10

-m —

20

N-n-

25

30 35 40

MONTHS

N-I ! N

MODAL GROUPS

45

50 55 60
N+I L

65 70
N + H

Figure 8.-

-Cirowth curve of yellowfin tuna taken in Hawaiian waters fitted to lengths witli actual modal values in

length superimposed.

142

FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE

AGE GROUP

250

200

w 150

Q

■z.

o

a.

; 100

UJ

50

I

IT

m

IS

•

•

^

• •• •

/

1

i_- n-»«

• 1

•

1 1 1

1 1

1 1

1 1

10

N-m-

15

20

25

N-It-

30 35 40

MONTHS

N-L— L

45

50

N -

MODAL GROUPS

55

N+I

60

G5

70

N+tt

Figure 9. — Growth curve of yellowfin tuna taken in Hawaiian waters fitted to lengths and transformed into terms

of weight. Actual modal values in weight are superimposed.

150 I-

u 100

50

AGE GROUP
I 1

18 24

MONTHS

30

36

42

Figure 10. — Lengths of dominant size groups of yellowfin
taken in waters off Central America by Schaefer (1948)
plotted against calculated growth curve of Hawaiian
yellowfin.

Schaefer that the 60-cin. fish probably are 1 year
old and the 85-cm. fish a year older is also in close
agreement.

Our growth curve indicates that the yellowfin
tuna grows rapidly during at least the earher years
of life. Group N demonstrates a gain in weight
of approximately 60 pounds in 1 year. Aikawa
and Kato (1938) and Kimura (1932) have studied
age and growth of the yellowfin tuna in Japanese
waters. Aikawa and Kato assigned ages by the
study of marks on vertebral centra which they
considered to be annuli. The resulting age-weight
relation is shown in figure 11. In plotting these
data, which are from table 3, it was assumed that
the ma.ximum values were representative of the
end of the year of life because the length and
weight values for age group O were maximum
values. As the month of June has been used in
our study as being the approximate center of the

AGE AND GROWTH OF YELLOWFIN TUNA

143

AGE GROUP

Figure 11. — Growth in weight plotted against age for
Hawaiian yellowfin as compared to growth curves
calculated by Aikawa and Kate (1938) and Kimura
(1932).

spawning period, the maximum values as given by
Aikawa and Kato have been plotted for the
month of June, the assumed last month for any
age group. Regardless of the month of the year
these values are plotted against, the valu's for
any given age group differ greatly from the values
resultin£,- from our study of the Hawaiian yellowfin.

T,\BLE 3. — Age, length, and weight range of yellowfin
tuna from Japanese waters, from Aikaioa and Kato
(1938)

Age group

Length in
centimeters

Weight in
kilograms

Weight in
pounds

Less than 38

38 to 54

Le.ss than 1.5

l.S to 4.3

I...

3 3 to 9 5

H

54 to 70

70 to 85

4.3 to 8.6. . . .

9.5 to 19

in

8.6 to 14.0

19 to 30 9

IV

85 to 100

14.0 to 21.4

21.4 to 34.0

34.0 to 44.0

44.0 to 57.5

57.5 to 75.0

.10 9 to 47 2

V

100 to 115

VI .

115 to 130

7S to 07

VII

130 to 145

VIII

145 to 160

The results of Kimura's (1932) age-weight study
also are shown in figure 11. This study is based
on a few specimens taken over a long period with
no defined method of determining modal values
in frequency distributions. The presentation of
Kimura's data is based on values of weight taken
directly from his growth curve shown in figure 12.
Values were converted to pounds for comparison
with our data. This growth curve demonstrates
more rapid growth than the curve of Aikawa and
Kato hut still does not agree with the present
Hawaiian study.

Figure 13 gives growth curves of other species

of tuna taken from various areas in the world
compared to the growth curve of Hawaiian yellow-
fin. We have plotted these from the published
data. This graph shows no other tunas as having
a growth rate as rapid as that of the yellowfin tuna
of Hawaiian waters. The curve of bluefin tuna
of the Mediterranean Sea (Sella 1929) is based on
more than 1,500 vertebrae samples. This growth
curve, like the growth curve of yellowfin based on
vertebra-centra analysis (Aikawa and Kato 1938),
shows a very slow growth rate and infers a very
long-hved fish, for most of the plotted data are
below the point of inflection.

BODY WEIGHT
KG.

50

20

A-

V

A

/

J^

J'

^

n< Mtnni

IMllMUM

\iinmill

I a m IS T Tcr

AGE GROUP

FiatjRF. 12. — Growth curve of yellowfin tuna in Japanese
waters from Kimura (1932). Circles show average
weight of a large number of fish of roughly equal
weight taken at one time. Solid dots are weights of
single fish.

Aikawa and Kato (1938), in addition to their
study of the yellowfin, determined ages and growth
of the black tuna {Thunnus orientalis), the bonito
or skipjack {Katsuwonus vagans), and the albacore
(Germo germo) by vertebral-centra analysis. Be-
cause the skipjack and albacore are smaller species
of tuna not comparable to the yellowfin, they have"
not been included in the graph. The growth
curve of the black tuna, a species more comparable
in size, indicates a more rapid growth rate but the
curve has only the slightest suggestion of an in-
flection point. The growth curve of bluefin tuna
(bl^ck tuna of Aikawa and Kato, Thunnus orien-
talis) by Kimura (1932) from weight frequencies

144

FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE

350

300

o

z
=)
o

•± 150

100

50

^

BLACK TUNA

/

HAWAIIAN
YELLOWFIN /

/ /

m^

1 /^

/ /

/^SELLA
/^ BLUEFIN

/ KIMURAjf/ /
/ BLUEFIN / /

*yy^

r

1

^^i^

•^ — ^^

* BLACK TUNAOF AIKAWA
1

ni

AGE GROUP

■2L

■m

Figure 13. — Age-weight curves of tunas from waters off Japan and Mediterranean Sea compared to curve of Hawaiian

vellowfin.

demonstrates the most rapid growth but shows no
semblance of a point of inflection. As the curves
have been fitted to the data by eye, there may be
errors in the interpretation, but the curves show
the great variation in results of age and growth
studies of tunas.

Westman and Neville (1942), in a study of 751
length frequencies of bluefin tuna (Thunnus thyn-
nus) taken in waters off New York by both the
troll and chum fisheries, show the catch to be
made up of three distinct age groups. Ages were
assigned by scale readings. A comparison of size
of fish by ages with the Hawaiian -yellowfin study
shows more similarity than the curves indicate in
figure 13. Even so, the growth rate of the Atlantic
bluefin as shown by plotted data (fig. 14) is not
so rapid as yellowfin growth during the early years
of life.

150 r

100

50

AGE GROUP

18 24

MONTHS

30

36

42

Figure 14.— Lengths of dominant size groups of bluefin
tuna taken off Long Island, New York, by Westman
and Neville (1942), plotted against the calculated growth
curve of Hawaiian yellowfin.

AGE AND GROWTH OF YELLOWFIN TtTNA

145

In general, the results of our study of weight
frequencies of Hawaiian yeliowfin tend to disagree
with results of some studies of other species of
tuna and even with comparable yeliowfin studies.
Group A^, present in the Hawaiian long-line catches
of both 1948 and 1949, is with little doubt an age
group demonstrating a weight gain of about 60
pounds in the calendar year. Wliether or not our
conclusions about age are correct in other respects,
the yeliowfin tuna of Hawaiian waters undoubt-
edly is a rapid-growing species.

CONCLUSIONS

1 . The yeUowfin tuna {Neothunnus macropterus)
in Hawaiian waters is a rapid-growing fish demon-
strating at least during part of its life a growth of
approximately 60 pounds in one calendar year.

2. Positions of modes of size frequencies are
well fitted by a growth curve calculated by Wal-
ford's graphic transformation method, having an
upper asymptote at 294.9 pounds.

3. Extrapolation of the calculated curve down-
ward shows the spawning period in reference to
mode A^ to be in year A'^— III. If this interpreta-
tion is valid, mode TV is composed of fish which
were completing their third year of life and enter-
ing their fourth in the middle of the calendar year
of observation.

Using the customary designation of age groups
according to completed years of life, they would
be designated age group II until the middle
of the spawning season which occurs in the mid-
dle of the calendar year, and then become age
group III.

LITERATURE CITED

AiKAWA, HiROAKi and M. Kato.

1938. Age determination of fish (Preliminary Rept. 1).
Bull. Jap. Soc. Sci. Fi.sh., vol, 7, No. 1, pp. 79-88,
8 figs. In Japanese with English summary. Transla-
tion from the Japanese by W. G. Van Campen.

BONHAM, KeI.SHAW.

1946. Measurements of some pelagic commercial fishes
of Hawaii. Copeia, 1946, No. 2, pp. 81-84, 2 figs.
Brock, Vernon E.

1944. Contribution to the biology of the albacore
(Oermo alalunga) of the Oregon coa.st and other parts
of the North Pacific. Stanford Ichth. Bull., vol. 2,
No. 7, pp. 19-248, 19 figs.
JcNE, Fred C.

1950. Preliminary fisheries survey of the Hawaiian-
Line Islands area: Part I — The Hawaiian long-line
fishery. U. S. Fish and Wildlife Service, Comm. Fish.
Review, vol. 12, No. 1, pp. 1-23, 18 figs.

KiMURA, KiNOSUKE.

1932. Growth curves of the blue-fin tuna and yellow-
fin tuna based on the catches near Sigedera, on the
west coast of Prov. Izu. Bull. Jap. Soc. Sci. Fish.,
vol. 1, No. 1, pp. 1-4, 5 figs. In Japanese with
English summary. Translated from the Japanese by
W. G. Van Campen.

KlSHINOUYE, KaMAKICHI.

1923. Contributions to the comparative study of the

so-called scombroid fishes. Jour. College of Agric,

Imperial Univ. Tokyo, vol. 8, No. 3, pp. 293-475,

26 figs.
Okamoto, Gokozo.

1940. On the weight composition of skipjack schools

in the northeastern sea area. Bull. Jap. Soc. Sci.

Fish., vol. 9, No. 3, pp. 100-102, 2 figs. In

Japanese with English synopsis. Translation from

the Japanese by W. G. Van Campen.
Partlo, J. M.

1950. A report on the 1949 albacore fishery (Thunnus

alalunga). Fish. Res. Bd. Canada, Pac. Biol. Sta.,

Cir. 20, pp. 1-37.
Petersen, C. G. J.

1922. On the stock of plaice and the plaice fisheries in

different waters. A survey. Rept. Danish Biol.

Sta., vol. 29, pp. 1-36, Copenhagen.

SCHAEFER, MiLNER B.

1948. Size composition of catches of yeliowfin tuna
(Neothunnus macropterus) from central America, and
their significance in the determination of growth, age,
and schooling habits. U. S. Fish and Wildlife Service,
Fish. BuU., No. 44, vol. 51, pp. 197-200, 4 figs.
Sella, M.

1929. Migrazioni e habitat del tonno (Thunnus thynnus
L.) studiati col metodo degli ami, con osservazioni
su I'accrescimento sul regime delle tonnare, ecc. R.
Comit. Talasso. Ital. Memoir 156, pp. 1-24, 2 figs.

>

v>

146

FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE

Snedecor, Georoe W.

1946. Statistical methods. Iowa State College Press,
Ames, Iowa. 4th Ed., xvi + 485.
Walford, Lionel A.

1946. A new graphic method of describing the growth
of animals. Biol. Bull., vol. 90, No. 1, pp. 141-147,
4 figs.
Westman, J. R. and P. W. Gilbert.

1941. Notes on age determination and growth of the
Atlantic bluefin tuna, Thunnus ihynnus (Linnaeus).
Copeia, 1941, No. 2, pp. 70-72, 3 figs.

Westman, J. R. and W. C. Neville.

1942. The tuna fishery of Long Island, New York.
Pp. 1-31, 12 figs. Board of Supervisors, Nassau
County, Long Island, New York.

APPENDIX

The following tables of data on yellowfin tuna
are those on which the figures and calculations in
the text are based.

Table A. — Weight frequencies of yellowfin tuna taken by
long-line fishing and landed at Honolulu during November
and December 1947

Class interval

70 to 79 pounds.. -
80 to 89 pounds.. -
90 to 99 pounds...
100 to 109 pounds.
110 to 119 pounds.
120 to 129 pounds.
130 to 139 pounds.
140 to 149 pounds.
150 to 159 pounds.
ItiO to 169 pounds.
170 to 179 pounds.
180 to 189 pounds.
190 to 199 pounds.
200 to 209 pounds.
210 to 219 pounds.
220 to 229 pounds.
2.30 to 239 pounds.
240 to 249 pounds.
250 to 259 pounds.
260 to 269 pounds -

Total.

November

December

Number of

tuna

landed

2

2

2

2

3

12

13

10

18

20

17

6

9

5

2

3

1
133

Table B. — Weight frequencies of yellowfin

tuna taken by long-li

ne fishing and

landed

at Honolulu d

iring 194S

Class interval

January

Febru-
ary

March

April

May

June

July

August

Septem-
ber

October

Novem-
ber

Decem-
ber

Number
of tuna
landed

1
1
2
2
5
6
9
2
I
8
3
11
8
7
5
5
6
5
4
1

1

1

1
1

3

6

1

1

5

2

2

6

31

55

45

39

25

37

44

19

25

19

16

8

1
2
3
2
3
3

10
8

18

10
8
5
6

10
4
2
2

6

1
7
4
2
4

4
1
1
4
3
3
3
1
1

1
3
8
4
3
2
3
6
5
8
6
5
2
4
1

1

1

2

4
4

7

20

34

24

18

17

11

12

5

8

7

1

3

21

2
4
7
3
4
1
4
6
5
4

2
3

8
19

15
9
6
3
8
9
3
1
2
4
3

I

16

80

90

60

25

40

30

51

34

29

30

18

15

3

2

2

1

31

6
13
54
68
45
29
30
24
24
24

9
13
17

3

3

3
10
41
71
59
53
46
49
49
40
46
37
21
11

3

45

90 to 99 pounds

1

9
3
11

8

8

4
3
2
2

79

268

110 to 119 pounds

361

272

130 to 139 pounds

218

140 to 149 pounds

199

198

160 to 169 pounds

216

170 to 179 pounds

147

1
1

142

190 to 199 pounds _

125

200 to 209 pounds

85

46

1

10

2

4

1

1
1

4

2

260 to 269 pounds....

1

1

Total

40

61

45

60

97

362

530

542

381

179

99

92

2,488

AGE AND GROWTH OF YELLOWFIN TXINA 147

Table C. — Weight frequencies of yellowfin tuna taken by long-line fishing and landed at Honolulu, 19/i9

Class interval

January

Febru-
ary

March

April

May

June

July

Auftust

Septem-

October

Novem-
ber

Decem-
ber

Number
o( tuna
landed

1

1

I

1

I

1

2

1
4

12
5

I
2

,1
7
4
1
4
8
3
6
5
5
3

1

1

2

6

1
2
2

5

1
1

3'

1
3

3
1
2
24
23
11
16
20
18

12
5
4
2
5
3
2

4
2
10
9
7
6
3
4
4
4
3
4
3
2

14

3
16
52
77
68
65
42
51
47
42
28
17
21
9
4
1

1

6

2

10

23

23

19

12

16

12

9

8

5

13

4

2

4

6

8

4

10

11

12

10

7

7

6

3

6

2

4

1

30

2

9
11
8
14
9
4
1
2
4
1
1

2
20
62
51
52
60
56
63
43
33
15
17
18
13
5
3

4

7
39
58
37
46
39
37
31
30
17
20
20
10
2
1

57

90 to 99 pounds ...

2
2
2
9

1

3

1
4

I

2"

109

2
1

I
4
1
1
2
2

217

110 to 119 pounds

249
238

130 to 139 Dounds

251

140 to 149 pounds

150 to 159 pounds

191
199
ISS

170 to 179 Dounds

144

180 to 189 pounds

1

84

190 to 199 DOunds

7C

1

82

1

1

45

1
1

1

17

6

1

2

1

1

Total

39

73

20

67

158

514

545

400

165

102

31

67

2,181

Table D. — Weight frequ

incies of yellowfin tuna taken by long-line fishing and landed

at Honolulu, 1948 and 1949 combined

Class interval

January

Febru-
ary

March

April

May

June

July

August

Septem-

October

Novem-
ber

Decem-
ber

Number
of tuna
landed

I

1

1

3

2

9

8

19

11

8

14

6

15

12

11

8

9

9

7

4

2

2

1

2

1
1
I
4
6
12
4
5
1

7
8
4

I

3

8

1
5
19
9
2
6
2
5
5
2
5
5
5
3
1
2

1
3
10
23
11
7
3

14

8
14
11
10
5
4
1
1

1

3

3

5

32

42

28

25

26

21

15

21

g

5

4

9

6

2

1

1

2
2

1

5

3

8

8

41

78

68

58

37

53

56

28

33

24

29

12

2

2

1

2

3

2

5

5

12

17

19

11

11

6

10

11

4

4

2

1

1

2

1

12

1
1
2
10
20
11
25
17
12
8
6

3
3

4

8

7

15

24

44

35

30

27

18

19

11

11

13

3

7

1

35

2

6

32

132

167

128

90

82

81

98

76

57

47

39

24

7

3

2

1

61

80 to 89 pounds

8

33

116

119

97

89

86

87

67

57

24

30

35

16

8

3

7

17

80

129

96

99

85

86

80

70

63

57

41

21

5

1

1

102

188

100 to 109

485

610

120 to 129 pounds

510

130 to 139 pounds

469

390

150 to 159 pounds

397

160 to 169 pounds

381

170 to 179 pounds

291

180 to 189 pounds

2
1

226

195

167

210 to 219 DOunds

91

1

27

10

1

6

1

3

260 to 269 pounds

1

1

Total -. -

79

134

65

127

255

876

1.075

942

546

281

130

159

4.669

Table E. — Weight frequencies

f yellow

fin tuna taken by live-bait fishing and trolling and landed at Honol

ulu during 1949

Class interval

January

Febru-
ary

Marcb

April

May

June

July

August

Septem-

October

Novem-
ber

Decem-
ber

Number
of tuna
landed

22
1
1

15

54
1

76

6
1

3

1

12

1

I
13

4

30 to 39 pounds

2

i

1

32

Total

7

3

1

14

39

57

1

2

124

148

FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE

Table F. — Weight frequencies of yellow fin tuna taken by long-line and live-bait fishing and landed at Honolulu during I948

and 1949

Class interval

to 9 pounds

10 to 19 pounds

20 to 29 pounds- --
30 to 39 pounds.-.
40 to 49 pounds...

50 to 59 pounds

60 to 69 pounds...
70 to 79 pounds...
80 to 90 pounds...
90 to 99 pounds...
100 to 109 pounds.
110 to 119 pounds.
120 to 129 pounds.
130 to 139 pounds.,
140 to 149 pounds..
150 to 159 pounds.
160 to 169 pounds..
170 to 179 pounds..
180 to 189 pounds.
190 to 199 pounds..
200 to 209 pounds..
210 to 219 pounds..
220 to 229 pounds..
230 to 239 pounds..
240 to 249 pounds. -
250 to 259 pounds..
260 to 269 pounds..

Total

January

Febru-
ary

137

March

66

April

May

1
294

8
33
116
119
97

933

July

32

132

167

128

90

82

81

98

76

57

47

39

24

7

3

2

1

1,076

August

7

17

80

129

96

99

85

86

80

70

63

57

41

21

5

1

1

944

Septem-
ber

October

Novem-
ber

130

Decem-
ber

Number
of tuna
landed

76
12

12

35

61

102

188

485

610

510

469

390

397

381

291

226

195

167