Table 1 Summary of catch and effort in the Japanese Atlantic longllne fishery, 1956-65 



[Estimates, adjusted for the whole fleet on the basis of sample in each year. Symbol p represents 500 fish or less.] 



^ Includes striped marlin 



2 Includes spearflsh and sallfish 



Rank correlation between fishing effort and 

 catch rates for 1965 shows that the fishermen 

 directed their effort efficiently with respect 

 to the total abundance of all species and to 

 yellowfin tuna and albacore combined, but in- 

 efficiently with respect either to yellowfin tuna 

 or to albacore. This relation is consistent with 

 the partial move in fishing effort back to 

 yellowfin tuna areas in 1965 after the distinct 

 shift in 1964 to albacore areas. 



Catches of yellowfin tuna and albacore by 

 area are given in tables 3 and 4. Catch rates 

 for yellowfin tuna, albacore, bigeye tuna, and 

 blue marlin over the 10 years are shown in 

 figure 2. 



Mean catch rates, 1956-65, for yellowfin 

 tuna, albacore, and blue marlin for the II 

 areas are presented in tables 5 to 7, (Only 

 these three species show clear declines in 

 apparent abundance.) The mean rate was de- 

 termined by adding the rates for all the months 

 in which the area was fished and dividing by 

 the number of months. The rate of decline in 

 apparent abundance for each species in each 

 area was calculated as the slope of a straight 

 line fitted to logarithms of monthly catch 

 rates, beginning with the first month of fish- 

 ing in the best year. If the correlation coeffi- 

 cient (r) was significant at P = 0.05 level or 

 less, the decline was accepted as real--other- 

 wise it was rejected. 



Declines are apparent for yellowfin tuna in 

 all 11 areas, for albacore in 5 of the 11 areas, 

 and for blue marlin in 7 of the 11 areas. The 

 nunnber of areas showing declines increased 

 over the 1956-64 period (Wise, 1968), which 



itself showed an increased number of declines 

 over the 1956-63 period (Wise and Le Guen, in 

 press). In addition to the increased number of 

 areas which show declines, the rates of de- 

 cline themselves appear to be increasing for 

 yellowfin tuna and blue marlin. We compared 

 the decline rates calculated over 10 years of 

 the fishery with the decline rates calculated 

 over the first 8 years. Of the 20 comparisons 

 possible for yellowfin tuna and blue marlin 

 (fishing was negligible in the Gulf of Mexico 

 before 1963), 11 show increases in declines 

 or declines where none previously existed, 

 3 show no decline or equal decline, and only 

 6 have a decrease in rate of decline. In other 

 words, the decline rates appear to be accele- 

 rating for these two species. 



Le Guen and Wise (1967) estimated that an 

 annual equilibrium yield of about 550,000 

 yellowfin tuna could be taken from the Gulf of 

 Guinea, Guianas, North Oceanic (East), Cape 

 Verde, Caribbean, and North Oceanic (West) 

 areas (the best yellowfin tuna areas), with a 

 total annual fishing effort of about 12 million 

 hooks. They also estimated an annual equi- 

 librium yield of about 165,000 yellowfin tuna 

 from the rest of the Atlantic with an effort of 

 about 3 million hooks. 



The catch of yellowfin tuna in the best 

 yellowfin tuna areas in 1965 was some 720,000 

 fish taken with almost 56 million hooks. These 

 figures represent a yield only 31 percent over, 

 despite a fishing effort more than 360 percent 

 over, the estimated equilibrium figure. 



The catch of yellowfin tuna in the rest of the 

 Atlantic was about 213,000 fish in 1965, 29 



