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STATUS REPORT: ATLANTIC BIGEYE TUNA 



by 



Atilio L. Coan, Jr. and Wesley Parks 



Southwest Fisheries Center 



Oceanic Fisheries Resources Division 



La Jon a, California 



ABSTRACT 



Recent total annual Atlantic catches of bigeye tuna have averaged 

 41,000 mt. Major participants in the fishery include Japan, Korea, Spain, 

 and the USSR. The U.S. takes bigeye along with yellowfin and skipjack tuna 

 in its eastern Atlantic tropical tuna purse seine fleet. Recent U.S. 

 catches have been less than 500 mt. 



The stock structure of bigeye tuna in the Atlantic is uncertain. 

 Hypotheses include a single Atlantic-wide stock and separate north and 

 south stocks. Catch-per-unit-effort shows slight decreasing trends. 



Production model analysis estimates MSY in the range of 52,000-123,000 

 mt. Recent catches are below MSY. Recent estimated effort levels are 25 

 to 50% less than optimum effort. Analyses suggest that with current 

 fishing patterns, increasing age-at- first-capture would slightly increase 

 equil ibrium yield- per-recruit. 



The International Commission for the Conservation of Atlantic Tunas 

 adopted a minimum size limit of 3.2 kg for bigeye tuna in 1979. The 

 regulation, intended to increase yield-per-recruit, has not been in effect 

 long enough for its effectiveness to be assessed. 



