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DESCRIPTION OF THE FISHERY 



Bigeye tuna are distributed throughout the Atlantic Ocean between 50 

 N and 40° S latitudes (Figure 1). Catches in the north Atlantic are 

 concentrated in the west at 40° N latitude and in the east at 20° N 

 latitude. South Atlantic catches are concentrated in the west at 30° S 

 latitude and in the east at 10° S latitude. 



I. A. History of the Fishery 



The Atlantic fishery for bigeye tuna began in 1956 when the 

 Japanese longline fleet expanded operations from the Pacific into the 

 Atlantic Ocean, Longline continues to be the principal gear capturing 

 bigeye. However, in recent years surface gears (purse seine and baitboat) 

 have taken a greater proportion of the catch (from 17% in 1972 to 37% in 

 1978). The surface fishery for bigeye tuna is a multi-species fishery 

 which also takes yellowfin and skipjack. 



The major participants in the north Atlantic fishery are the 

 Japanese, Korean, Spanish, and Portuguese fleets. These fleets together 

 caught 80% of the average north Atlantic bigeye catch during the period 

 1975 to 1979 (Figure 2a). 



The major participants in the south Atlantic fishery for bigeye 

 tuna are the fleets of Japan, Korea, Russia, and Taiwan. These fleets 

 caught 74% of the south Atlantic catch of bigeye during the period 1975 to 

 1979 (Figure 2b). 



I.B. Trends in Catch and Effort 



I.B.I. North Atlantic Fishery 



Catches for the north Atlantic longline fishery peaked in 

 1974 at 26,000 mt and decreased to approximately 10,000 mt in 1979 (Figure 

 3a). Catches for the surface fishery also peaked in 1974 at 13,000 mt and 

 averaged 10,000 mt during the 1975 to 1979 period. The provisional 1980 

 north Atlantic longline and surface fishery catch is 21,400 mt. 



Fishing effort (in number of hooks) for bigeye tuna in 

 the north Atlantic reached a peak of 165 million hooks in 1975, then 

 decreased to 85 million hooks in 1977 (Figure 4a). Effort for the Canary 

 Island baitboat fleet however, remained relatively constant (10,000 days at 

 sea) during the 1975 to 1978 period (Figure 4b). 



