500 

 00*) 

 400- 



3 



3 300 



5 200 



Z 



§ 



100 



PACIFIC 



1962 



Japanese longline fishery from 1962 to 1970 is 

 shown in Figures 14, 15, and 16. 



Figure 13. — Annual fishing effort (number of hooks), by 

 ocean, of the Japanese tuna longline fishery, 1962-70. 



bluefin tuna in the higher latitudinal waters where 

 billfishes are generally not found. 



The general leveling of the yield of billfishes fol- 

 lowing the full coverage of the billfish distributional 

 range by the longline fishery may be indicative, as in 

 the case of the larger tunas, that some of these 

 species are already being fished near the level of 

 maximum sustainable yield. 



The relationship between catch and effort for the 

 various species, based on Japanese longline data 

 (Fisheries Agency of Japan, 1972), is next examined. 

 The annual Japanese longline fishing effort in terms 

 of numbers of hooks fished, for the years 1962-70, is 

 shown in Figure 13. The total fishing effort for all 

 oceans remained relatively stable at around 450 mil- 

 lion hooks. This is the result of the Japanese fishery 

 policy (in effect since 1963) of controlling fleet size in 

 order to effect the rational utilization of the tuna 

 resources and to maintain the tuna fishing industry 

 on a sound foundation. 



Of the total 450 million hooks, roughly two-thirds 

 of the effort, or 300 million hooks, was expended in 

 the Pacific Ocean. This level of effort has remained 

 relatively steady in the Pacific since 1964. 



The fishing effort was about the same in the Indian 

 and Atlantic Oceans in 1963, but became slightly 

 greater in the Atlantic in 1964-65. Since 1965 it has 

 been considerably greater in the Indian Ocean. This 

 shift in effort was due to a decrease in catch in the 

 Atlantic Ocean and the subsequent movement of 

 vessels into the southern bluefin tuna grounds of the 

 Indian Ocean. Since 1968 there appeared to be a 

 trend toward decreasing effort in the Indian Ocean 

 and increasing effort in the Atlantic Ocean. 



The catch of billfishes. by species, by the 



(10*) 



Figure 14. — Annual catch, in numbers, of the four major 

 billfish species in the Pacific Ocean. 1962-70 (from Kume, 

 in press). EPR, SPR, and NPR denote eastern Pacific 

 region (east of long. 1 30°W), South Pacific region (south of 

 lat. 5°N, west of long. 130°W), respectively. 



Pacific Ocean 



The Pacific Ocean was subdivided into the follow- 

 ing three regions (Fig. 14): the eastern Pacific region 

 (east of long. 130 C W), the North Pacific region (north 

 of lat. 5°N, west of long. 130°W), and the South 

 Pacific region (south of lat. 5°N, west of long. 

 130°W). 



Swordfish — The yearly catches of swordfish var- 

 ied little, numbering about 200,000 per year on a 

 Pacific-wide basis. However, taken by regions, a 

 slight decrease was noted in the North Pacific re- 

 gion, particularly after 1967. The catch in the eastern 

 Pacific region increased after 1968 as a result of 

 fishing in swordfish waters of Baja California and 

 Ecuador. 



Striped martin — Since 1963 the eastern Pacific re- 

 gion has been the most productive of striped marlin 



