was postulated that the 52-cm. size group would 

 consist of 1-year-old fish (14 months), the 65 cm. 

 size group 2-year-old fish, etc. 



Regarding spawning of the albacore, it 

 appears that first maturity may be reached by 

 some of the larger fish in the 85 -cm. size group 

 (4-year-olds), since examination of fish caught 

 near Guadalupe Island during July and August 

 1953 revealed that those in the 93- and 100-cm. 

 size groups had recently spawned. Apparently 

 these large albacore had spawned prior to their 

 coastward migration from the mid-Pacific, 

 which i s in progress primarily from June to 

 September for large fish and from May to August 

 for smaller ones. This means that albacore 

 spawning may occur in the west-central Pacific 

 during the period preceding an annual coastward 

 migration, for it seems unlikely that they would 

 spawn en route. Based on the reported capture 

 of small albacore, 23 cm. long, about 500 miles 

 west of Midway Island from January to May 1937, 

 139 albacore from 30 to 37 cm. long in the Japa- 

 nese coastal fishery in June 1951, and young 

 albacore 18.8 and 12.4 cm. long caught in May 

 1949 and June 1952, it is believed that spawning 

 probably takes place during the winter or spring. 

 Most of the albacore comprising the California 

 fishery originate between the longitude of Japan 

 and the Hawaiian Islands (probably nearer the 

 Islands) and migrate into the West Coast fishing 

 grounds during the first season they become 

 strong enough to school and endure along mi- 

 gration. 



Collette, Bruce B. 



A preliminary review of the tunas of the 

 Genus Thunnus . /Conference Paper 

 VI - 17 



This is a first step in a proposed revi- 

 sion of the large tunas of the world. The arti - 

 ficiality of splitting the Scombridae into the 

 families Thunnidae, Cybiidae, and Katsuwonidae 

 and placing the Thunnidae and Katsuwonidae in a 

 separate order, the Plecostei, has been shown 

 by a number of workers. The differences be- 

 tween Thunnus South, Parathunnus and Neo - 

 thunnus Kishinouye , Germo Jordan, and 

 Kishinoella Jordan and Hubbs are specific, not 

 generic. The species of Thunnus have been 

 greatly split as a result of using even smaller 

 differences as specific differences, since spe- 

 cific differences were used to separate genera. 



Although further and more detailed study 

 is necessary, present evidence indicates that 

 there are only six species of great tunas in the 

 world: albacore (T. alalunga), yellowfin (T. 

 albacares), blackfin (T. atlanticus), bigeye (T. 

 obesus), bluefin (T. thynnus), and longtail (T. 

 tonggol ). 



Synonymies are presented a s tentative 

 allocations of the many names that have been 

 applied to the tunas, both generic and specific. 

 The generic names Thynnus Cuvier, Orcynus 

 Cuvier, Orcynus Cooper, Albacora Jordan, 

 Germo Jordan, Parathunnus Kishinouye, Neo- 

 thunnus Kishinouye, Kishinoella Jordan and 

 Hubbs, and Semathunnus Fowler are placed as 

 synonyms of Thunnus Suuth. The six species 

 are designated as above with the recognition of 

 two subspecies of bluefins, T. thynnus thynnus 

 from the Atlantic and T. thynnus orientalis from 

 the Pacific, on the basis of gill raker counts. 



Fujii, Yutaka; Koichi Mimoto, and 

 Shichiro Higasa 



Biochemical studies on the races of tuna. 

 Base composition of testi s deoxy- 

 ribonucleic acid (DNA). /Conference 

 Paper III - 3.7 ( See also Fujii, Yutaka 

 et al. Biochemical studies on the races 

 of tuna. Report of Nankai Regional 

 Fisheries Research Laboratory no. 9, 

 p. 136-142 (1958); no. 11, p. 1-6 (1959); 

 no. 12, p. 14-22, 23-32 (I960).) 



Studies of the relative proportion of the 

 bases adenine (a), thymine (t), guanine (g) , 

 cytosine (c), extracted from tuna testis deoxy- 

 ribonucleic acid have shown that characteristic 

 values of the ratio of (a+t) / (g+c) may be ob- 

 tained for bigeye, yellowfin, Indo-maguro, and 

 Goshu-maguro tunas. 



A study to relate these values to sub - 

 populations within each species is being carried 

 out. There is some evidence that the ratio of 

 bases in the testis DNA is different for the same 

 species collected from different areas. 



Hiyama, Yoshio, and Kenji Kurogane 



Morphometrical comparisons of tuna 

 from areas in the Pacific and I n d i a n 

 Oceans. /Conference Paper III -77 



Morphometric and meristic studies 

 were made of albacore, yellowfin, and bigeye 

 tunas. Five hundred ninety-six albacore were 

 examined, including 288 from the northwest 



24 



