76 



COMMERCIAL FISHERIES REVIEW 



Vol. 28, No. 7 



Japan (Contd.): 



so, from the northwest Pacific to the Indian 

 and Atlantic Oceans, and noted the steady rise 

 in catch from 110,000 metric tons in 1952 to 

 over 530,000 tons in 1962. He pointed out, 

 however, that, despite the rapid expansion 

 in fishing operations, resources in the fish- 

 ing areas began to decline perceptibly, and 

 production, after peaking in 1962, started to 

 fall off. It was also stated that Japanese re- 

 search and investigation lagged far behind the 

 rapid changes occurring in the fishery and 

 resources. 



Yellowfin : Based on Nankai Laboratory's 

 tuna data up to 1962, Uemura noted thatfish- 

 ing intensity continued at a very high level in 

 1962 and that even if efforts were increased 

 beyond the 1962 level, an increase in overall 

 catch could not be expected. Systematic re- 

 search and investigation of the tuna resources 

 in the eastern Pacific, conducted by the In- 

 ter-American Tropical Tuna Commission, 

 indicate that maximum sustainable yield in 

 the eastern Pacific is around 80,000 tons a 

 year. This quantity was reported to be some- 

 what more than the total yearly Japanese 

 long-line catch of yellowfin for the entire Pa- 

 cific Ocean. Mimura noted a marked decline 

 in hook rate in the Indian Ocean since the be- 

 ginning of operations in that ocean. Nakagome 

 reported that hook rate in the Atlantic Ocean 

 showed a marked decline since the com- 

 mencement of Japanese Atlantic operations. 

 Reproduction, mortality, and hook rates es - 

 timated by Tetsu for the years 1957 to 1963 

 brought out that increased fishing effort be- 

 yond the 1963 level could not be expected to 

 increase production. Catch statistics by 

 fishing grounds, prepared by Shiozawa and 

 his colleagues, show that since 1961 catch 

 has declined considerably despite increased 

 fishing effort. 



Big-eyed : Research on this species so 

 far has been confined to the Pacific Ocean. 

 Data compiled by Suda, Nakagome, and Kume 

 on the annual variation in hook rate for the 

 eastern Pacific, where big-eyed distribution 

 is heavy, show a marked decline since 1961. 

 Suda's study clearly shows evidence of a de- 

 clining trend from 1961 when Japanese fish- 

 ing operations began to expand to the eastern 

 Pacific off the American continent. Analysis 

 of resource trends based on data up to 1962 

 indicate that the fishing effort in 1960-61 ap- 

 proached the level of maxim^um yield. Thus, 

 caution was expressed with regard to in- 



creasing the fishing intensity beyond the 1961- 

 62 level. 



Albacore: Several papers on the mecha- 

 nisms of yearly change in the Pacific alba- 

 core population in the Northern Hamisphere, 

 contributed by Suda, showed wide changes in 

 fishing effort and population size. However, 

 over the entire period of fishing operations, 

 a stabilized situation was observed and the 

 yearly change in population size was primar- 

 ily attributed to changes in the occurrence of 

 recruitment. The survival rate of albacore 

 was estimated to be around 70 percent but 

 fishing intensity was believed not to have 

 reached a very high level. Otsu, in explain- 

 ing the albacore population off the U, S. coast, 

 stated that it was difficult to believe that fish- 

 ing has had any significant effect on the re- 

 source inasmuch as no declining trend has 

 been observed. 



Bluefin: Nakamura, Yamagami, and Ito, 

 in their report on the state of the bluefin re- 

 source off Japan, noted a prolonged cyclical 

 change in fishing conditions, which was be- 

 lieved to be due to environm.ental factors. 

 Research by Nakamura and Yamanaka into 

 the yearly changes in the length frequency of 

 bluefin indicated a possible close correlation 

 between change in fishing conditions and ap- 

 pearance of a dominant year-class group. 

 (Katsuo Maguro Tsushin, April 8, 11, & 13, 

 1966.) 



Note: See Commercial Fisheries Review , April 1966 p. 61. 

 ***** 



EXPORTS OF FROZEN TUNA TO U. S. AND 



CANADA, APRIL 1965 -MARCH 1966: 



Data released by the Japan Frozen Foods 

 Exporters Association show that in business 

 year 1965 (April 1965-March 1966) frozen 

 tuna (round, gilled and gutted, dressed with- 

 out tail, fillets and loins) approved for ex- 

 port to the United States and Canada from 

 Japan proper totaled 66,223 short tons valued 

 at US$25.7 million as compared to BY 1964 

 exports of 57,324 tons valued at $21 million. 

 Transshipments from overseas bases to the 

 United States and Canada totaled 50,180 short 

 tons valued at $14.4 million as compared to 

 BY 1964 exports of 36,334 tons valued at $10.5 

 million. The increase in transshipments of 

 13,846 tons was primarily accounted for by 

 albacore, which showed an 11,148-ton gain. 



Exports of frozen tuna to countries other 

 than the United States and Canada totaled 



