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 

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 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. 



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