Table 2. — Distribution of fishing effort in the Japanese Atlantic longline fishery by year and area, 1956-64 



Notes: 1. A new area, the Gulf of Mexico (GM) had 2,556,000 hooks in 1964, and 433,000 hooks in 1963. 

 2. This table embodies certain corrections of Wise and Le Guen's (in press) table 3. 



Table 3. — Catch rates and rates of decline for yellowfin 

 tuna, Japanese Atlantic longline fishery, 1956-64 



Table 4. — Catch rates and rates of decline for albacore, 

 Japanese Atlantic longline fishery, 1956-64 



Rate of decline calculated as slope of a straight 

 line (shown here as absolute value) fitted to logarithms 

 of monthly catch rates, beginning with the first month 

 of fishing in the best year. 



2 Highly significant (P = 0.01, or less). 



rates for all the months in which fishing 

 occurred in the area and dividing by the number 

 of months. The rate of decline in apparent 

 abundance for yellowfin tuna for each area is 

 also shown. This rate is calculated as the slope 

 of a straight line fitted to logarithms of monthly 

 catch rates, beginning with the first month of 

 fishing in the best year. If the correlation 

 coefficient (r) was significant at the P = 0.05 

 or less, the decline was accepted as real-- 

 otherwise it was rejected. 



When this table is compared with Wise and 

 Le Guen's table showing comparable values 

 for the 1956-63 period, it is apparent that catch 

 rates of yellowfin tuna continued to decline in 

 the seven areas of highest abundance, and that 

 the declines continued at about the same rates 

 as over the preceding several years. 



Evidently, by 1964 the level of yellowfin 

 abundance had fallen to the point where it was 

 more economical to concentrate on albacore, 

 as evidenced by the increased concentration of 

 fishing in albacore areas and the actual 



Rate of decline calculated as slope of straight line 

 (shown here as absolute value) fitted to logarithms of 

 monthly catch rates, beginning with the first month of 

 fishing in the best year. 



2 Highly significant (P a 0.01 or less). 



3 Significant (P - 0.05 or less). 



decrease in effort (in face of a general increase) 

 in the prime yellowfin tuna area, the Gulf 

 of Guinea (table 2). 



The reason for the decline in catch rates of 

 yellowfin tuna has been described by Le Guen 

 and Wise, 1967. They estimated that an 

 equilibrium yield of about 550,000 yellowfin 

 tuna could be taken annually from the best 

 yellowfin tuna areas --Gulf of Guinea, Guianas, 

 North Oceanic (East), Cape Verde, Caribbean, 

 and North Oceanic (West)--with a total fishing 

 effort of about 12 million hooks per year in 

 these areas. The annual equilibrium yield of 

 yellowfin tuna was predicted as some 715,000 

 fish, with an effort of about 15 million hooks 

 for the whole Atlantic (exclusive of the Gulf of 

 Mexico, where there was little or no fishing 

 before 1963). 



