a 







7 







e! s 







z 



f 4 



1/ Vl/7 \ S~^\ \ll\ / ^^ U / flLL SPECIES COMBINED 

 ALL TUNAS COMBINED' A/A A , 





= 3 



n/^*\\ / V /\/~\ F\^ 





s 







X £ 



r sVa~^v- 





' 



ALL B1LLFISHES COMBINED / vA/v W \ 



^x>C 



Figure 5. — Annual average catch per 100 hooks of tunas 

 and billfishes by Japanese longline vessels in the eastern 

 Pacific. 



It is interesting to note in Figure 5 that the total 

 catch rate, which leveled off in about 1964, is com- 

 prised of about half tunas and half billfish. It is 

 pointed out here that both the catch figures and the 

 catch per effort figures are expressed in terms of 

 number of fish rather than weight. If statistics based 

 on weight were available these trends would be 

 somewhat different. It should also be mentioned 

 that Figures 4 and 5 do not include data for the 

 Korean and Chinese catches and effort. However 

 since their catches are rather minor relative to those 

 of the Japanese, this fact should not alter the results 

 very much. 



The total annual catches of billfish and tuna taken 

 by Japanese longliners in the eastern Pacific are 

 shown by species, in Figure 6. In the billfish cate- 

 gory, sailfish and shortbill spearfish are combined 

 in one histogram for the reasons noted earlier and 

 they represent the greatest catches in terms of 

 numbers. The numbers of striped marlin caught fol- 

 low closely behind sailfish and shortbill spearfish 

 and in terms of weight far exceed them. The catches 

 of the other species, swordfish, blue marlin and 

 black marlin. are much less. All of the species ex- 

 cept swordfish showed a rapid increase to some 

 maximum, followed by a great deal of variability at 

 a somewhat lower average level. 



With respect to tunas, bigeye was the most abun- 

 dant species in the catch, followed by yellowfin, 

 albacore. skipjack, and bluefin. The catches of skip- 

 jack and bluefin are extremely low and can be con- 

 sidered incidental. 



Figure 6. — Total annual catch by species of tunas and 

 marlins captured by Japanese longline vessels in the east- 

 ern Pacific. 



250 



^ 200 



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