-143- 



STATUS REPORT: EASTERN TROPICAL PACIFIC YELLOWFIN TUNA 



by 



Samuel F. Herrick, Jr. 



Southwest Fisheries Center 



Oceanic Fisheries Resources Division 



La Jon a, Cal ifornia 



ABSTRACT 



The status of eastern Pacific yellowfin tuna has been evaluated using 

 general production models and age- structured models. Results of the 

 production model analyses indicate that the eastern Pacific yellowfin 

 fishery is currently operating at levels above maximum sustainable yield. 

 The age- structured analyses raise concerns over the increased dependency of 

 the fishery on age-1 fish. Recent increases in age-1 catches could lead to 

 a decrease in yield-per-recruit and a diminished potential yield. Heavy 

 fishing on a succession of poor recruit classes could reduce the adult 

 population such that recruitment failure occurs. Efforts to reverse these 

 trends in the near future are complicated by a failure to reach agreement 

 on a mechanism for implementing an eastern Pacific yellowfin conservation 

 program in 1980. 



