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3) Fecundity of yellowfin tuna off southern Brazil (ICCAT). 



4) Relationsip between occurrences of yellowfin tuna and sea 

 surface temperature (SWFC). 



5) Techniques to estimate economic value of the eastern Atlantic 

 surface fishery (SWFC). 



6) Status of stocks: production models, yield-per-recruit 



(SWFC). 



7) Management problems, alternative management schemes, sampling 

 problems (SWFC). 



IV. C. Future Research Needs 



Future research on Atlantic yellowfin tuna should center on the 

 following activities: 



1) Refining and extending studies of alternate management 

 schemes. Discrepancies in the data sets and procedures used in initial 

 analyses should be resolved. Effects of different management schemes on 

 multispecies catches, yield-per-recruit, economics, etc., should be 

 considered. 



2) Investigating the relationships between environmental 

 parameters and abundance, availability, and/or vulnerability of stocks. 



3) Investigating the interaction between surface and longline 

 gear. 



IV.C.l. Suggested Approach and Methods 



1) U.S. single-set data should be evaluated for possible 

 use in improving knowledge of species composition and fish size composition 

 of schools. A model should be developed to predict movements of the fishery 

 due to different management alternatives and to predict benefits to the 

 fishery, yield-per-recruit, undersize catches, and multispecies catches, 

 based on fishery, economic, and environmental assumptions. 



2) Data sets from other geographical regions, or 

 utilizing other species, could be used to test the technique of using sea 

 surface temperature to separate effort by species, for example. 



IV. D. Status of SWFC Data Base 



Data on Atlantic yellowfin tuna at the Southwest Fisheries Center 

 are currently considered adequate for population assessments. There are 



