JflN FEB MAR APR MAY JUr^E JOLl" AUG SEPT OCT rjOV DEC 



Figure 4. — Apparent seasonal abundance of juvenile al- 



bacore in Hawaiian waters, llHi^-C-j. 



SPAWNING 



Yoshida (1965) re.portecl that juvenile albacore 

 occur near the Hawaiian Islands and tacitly as- 

 sumed that albacore spawned in these waters. 

 The most direct method of determining the 

 sj^awning habits of fishes is to observe the spawn- 

 ing activity, where possible. Another method is to 

 determine the seasonal and areal distribution of 

 freshly fertilized ova and newly hatched larvae. 

 Because these observations are not available, how- 

 ever, inferences on spawning must be made on 

 indirect evidence. 



Otsu and Uchida (1959), who examined alba- 

 core ovaries, indicated that albacore in the central 

 and eastern North Pacific (between lat. 30° to 

 50° N. and t.he ISOth meridian to the U.S. west 

 coast) were either sexually immature fish or were 

 adults that did not show signs of being near 

 spawning. Adult albacore caught near Hawaii, 

 however, showed evidence of active spawning dur- 

 ing the summer. Furthermore, the northern limits 

 of the distribution of all tuna larvae in tlie longi- 

 tudes of the Hawaiian Islands are lat. 30° N. in 

 the summer and 25° N. in the winter (Walter M. 

 Matsumoto, personal cormnunication). Finally, 

 the wide size range of the juveniles around Hawaii 

 suggests that they probably do not move great 

 distances. I conclude, therefore, that albacore do 

 spawn in Hawaiian waters and that the resulting 

 juveniles spend at least part of their early life 

 in these waters. 



As noted earlier, the growth curve provided 



an estimate of early May as the time albacore 

 larvae hatched. For all practical jDurposes the 

 hatching and spawning periods can be consideretl 

 coincident; Matsumoto (1958) estimated that the 

 incubation (period of fertilized tuna ova was not 

 more than 4 days. The 5-percent confidence limits 

 for the extrapolated hatching cLate suggest that 

 albacore may spawn from March to September. I 

 can conclude that, albacore spawning around 

 Hawaii peaks in May and may extend from ]\Iarch 

 to September. These observations are not unlike 

 that of Otsu and Uchida (1959), who postulated 

 sununer siiawning for albacore in Hawaiian 

 waters. 



ACKNOWLEDGMENTS 



Glenn A. Flittner, Bureau of Commercial 

 Fisheries Fishery-Oceanography Center, La JoUa, 

 Calif., critically reviewed the manuscript and 

 made many helpful suggestions. Robert R. Bell 

 and William L. Craig, California Department of 

 Fish and Game, also read the manuscri2:)t. 



LITERATURE CITED 



AiKAWA, HiROAKi, and Masuo Kato. 



103S. Age determination of fish (preliminary report 



1). [U.S.] Fish Wildl. Serv., Sr>ec. Sei. Kep. Fish. 



21, 22 pp. (1050). Translated from Bull. Jap. Soc. 



Sci. Fish. 7(1) : 70-88. 

 ASANO, Masahiro. 



10(>4. Young albacore talicn from the northeastern 



sea area of Japan in August and September, 1963. 



Bull. Tohoku Reg. Fish. Res. Lab. 24: 20-27. [In 



Japanese with English summary and title.] 

 Bell. Robert R. 



1962. Age determination of the Pacific albacore of 

 the California coast. Calif. Fish Game 48 : 39^8. 



Clemens, Harold B. 



1961. The migration, age, and growth of Pacific 

 albacore ( Thv nnns ffermo), 1951-195S. Calif. Dep. 

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 Marr, John C, and Milner B. Schaefer. 



1949. Definitions of body dimensions used in describ- 

 ing tunas. [U.S.] Fish Wild!. Serv., Fish. Bull. 

 51: 241-244. 

 Matsumoto, W.m.ter M. 



1958. Description and distribution of larvae of four 

 .si)ecies of tuna in central Pacific waters. U.S. 

 Fish Wildl. Serv., Fish. Bull. 58 : 31-72. 



19<i2. Identification of larvae of four species of tuna 

 from the Indo-Pacific region I. Carlsberg Foun- 

 dation's Oceanographical Expedition round the 

 world 1928-30 and previous "Dana"-Expeditions. 

 Dana Rep. 55. 16pp. 



1963. Unique shape of the first elongate haemal spine 

 of albacore. Thiiniviis alalunga (Bonnaterre). 

 Copeia 1963: 460-462. 



210 



U.S. FISH AND WILDLIFE SERVICE 



