bv the existence of a dominant size group. With 

 the occurrence of one dominant size group, good 

 catches can be expected for the following 2 or 3 

 years. 



Index-P (formula explained in author's 

 previous report), used as a measure of the pop- 

 ulation size of each year class, showed similar 

 annual change in both species. 



As both index-S and index-P in both 

 species show similar changes, it is suggested 

 that the changes in year class size of albacore 

 and bigeye are caused by intraspecific and inter- 

 specific fac tor s. Since the patterns of distribu- 

 tion and population structures of the two species 

 are rather similar, some changes in environ- 

 mental conditions may cause similar changes in 

 the two populations. 



Suzuki, Akimi 



Blood types in tuna. /Conference Paper 

 III -2. J (See also Suzuki, Akimi et al. 

 Serological studies of the races of 

 tuna, I, II, III, IV and V. Report of 

 Nankai Regional Fisheries Research 

 Laboratory no. 8, p. 104-116 (1958) ; 

 no. 11, p. 17-23, 165-172 (1959); no. 12, 

 p. 1-13 (1960); no. 13, p. 53-67 (1961).) 



Investigation of the erythrocyte antigens 

 of albacore, bigeye, and yellowfin tunas by 

 means of normal and immune sera has shown a 

 variety of antigenic differences. 



In the albacore, the Tgl and Tg2 antigens 

 are recognized by rabbit immune sera. These 

 two antigens form a blood group system with 

 four phenotypes Tgl; Tg2; Tgl Tg2; and O (the 

 absence of Tgl or Tg2). In the bigeye, three 

 antigens are recognized, two of them very simi- 

 lar to Tgl and Tg2 of albacore. The antigen 

 bigeye-3also occurs in albacore taken from the 

 North Atlantic. Yellowfin appear to have antigen 

 y similar to Tg2 of albacore and bigeye. 



An investigation of the agglutinins in tuna 

 sera revealed that there area variety of "serum 

 types" reactive with human Aand/or B erythro- 

 cytes. 



Uchida, Richard N. , and Tamio Otsu 



Analysis of sizes of albacore occurring 

 in various Pacific Fisheries -A pre- 

 liminary report. /Conference Paper 

 VII - llj 



Published and u n p u b 1 i s h e d albacore 

 length frequency data from foreign and domestic 

 sources were analyzed to determine the general 

 age structure of the species and the contributions 

 of the several age classes to the major albacore 

 fisheries in the Pacific Ocean. 



Of the three major albacore fisheries in 

 the North Pacific, the U. S. West Coast fishery, 

 the Japanese winter longline fishery, and the Ja- 

 panese spring live-bait fishery, the last normally 

 accounts for the largest percentage of the total 

 catch. 



The 3-year-olds compose roughly 70 per- 

 cent of the American albacore landings, while 

 the 4- and 5-year-olds constitute a large part of 

 the Japanese landings. 



Australia and Chile have albacore fish- 

 eries, but they catch only a small portion ofthe 

 albacore landed in the South Pacific. The 

 smallest albacore are taken in waters around 

 Australia and New Zealand, and these are esti- 

 mated to be about 2- and 3-year-olds. In the 

 small coastal fishery of Chile, the 3-year-olds 

 predominate, making up roughly 71 percent of 

 the catch. 



The only major fishery for albacore in 

 the South Pacific is the Japanese tropical long- 

 line fishery. Fishing is concentrated in an area 

 between the Equator and latitude 30° S. , and 

 the predominant age group taken is the 6-year- 

 olds, which compose 42 percent of the total 

 landings. 



Tagging results have shown that the alba- 

 core of the temperate North Pacific belong to a 

 single population, but the relationship between 

 the North and South Pacific albacore has not 

 been determined. Evidence indicates, however, 

 that the stocks in the North and South Pacific 

 are independent of each other. 



Comparison of North and South Pacific 

 albacore landings indicates that 93 percent ofthe 

 fish taken in the North Pacific fisheries are im- 

 mature fish under 5 years old, while only 35 per- 

 cent of the South Pacific fish were estimated to 

 be under 5 years old. 



A commercial longline fishery compara- 

 ble to that found in the tropical South Pacific is 

 nonexistent in the tropical North Pacific. It is 

 hypothesized that one of the causes for this ab- 

 sence of a longline fishery in tropical waters of 

 the Northern Hemisphere is the fishing effort 

 expended on the immature stock (3- to 5-year- 

 olds) during its migration in temperate North 

 Pacific waters, with consequent reduction in the 



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