200,000 tons. Yellowfin tuna, which became the most impor- 

 tant element in the fishery in 1928, continued to dominate 

 the catch. Some years in the 1960's have seen catches of 

 100,000 tons of yellowfin tuna alone — as much as all species 

 combined a generation ago. Except for the catch of the 

 Japanese longline fleet, which has extended its operations 

 to the eastern Pacific within the decade, all of the tunas in 

 the eastern Pacific are taken at the surface and mostly by 

 nets (fig. 9). 



The statistics on the total catch tend to mask important 

 trends that become apparent only when the catch of each 

 species is examined. Scientists of the Inter-American 

 Tropical Tuna Commission have used catch statistics to 

 estimate the impact of the fishery on the yellowfin tuna 

 stock. Reviewing the record of the catch for the past several 

 decades, they have concluded that the yellowfin tuna popula- 

 tion is below the level at which maximum yield can be sus- 

 tained. They recommended a limitation of the catch to 

 79,300 tons in 1966. Similar studies on the companion 

 species, skipjack tuna, failed to show a corresponding link 

 between increased fishing pressure and the size of the stock. 

 Several years ago the scientists suggested that the skipjack 

 tuna stock could withstand a much higher level of fishing 

 effort and greater catches. 



In the past, albacore was one of the chief elements of the 

 eastern Pacific fish catch. It ceased to be so in the 19.30's 

 and has never yielded the tonnage that yellowfin and skip- 

 jack tuna do now. In 1963, the albacore catch was at its 

 peak figure, about 30,000 tons. Most of the albacore are 

 caught off' the coast of California, Oregon, and Washington. 

 The season usually lasts from June through October. 



Fishing for albacore begins off Baja California and moves 

 northward as the season progresses. The catch is subject to 

 drastic fluctuations, Matsumoto says. In 1926, it plummeted 

 to a tenth of its 1925 total of 11,000 tons and remained at 

 well under 1,000 tons for a decade, rising abruptly to its 



FIGURE 9. There is a Japonese soying; "Net — rich mon; pole and 

 line — beggor." The development of purse seining in the eostern 

 Pacific Ocean resulted in greatly increased cotches. 



17 



