-209- 



III. B. 5. Results of Other Analyses/Simulations 

 None available. 



1 1 I.e. Current Evaluation of Stocks and the Fishery 



Although the condition of the western Pacific yellowfin tuna 

 stock(s) is not certain, it appears that the stock is capable of sustaining 

 the current level of fishing, or perhaps more. It was estimated that the 

 MSY for the Pacific longline fishery for yellowfin tuna was around 80,000 

 to 90,000 mt and that increased longline fishing effort was unlikely to 

 result in a significant increase in sustained catch. 



IV. STATUS OF CURRENT RESEARCH NEEDS AND EFFORTS 

 IV. A. Major Research Problems 



The following factors need to be determined: 



1) Growth parameters of western Pacific yellowfin tuna. 



2) The relation and the extent of mixing of fish available to 

 surface gear and longline gear. 



3) Yield-per-recruit estimates: It has been pointed out that the 

 surface fisheries in the Philippines may be making substantial catches of 

 small yellowfin tuna, which is not good from a yield-per-recruit 

 standpoint. 



In addition, production model analysis incorporting surface catch 

 and effort data should be undertaken. 



IV. B. Current Research Efforts 



A background paper on a preliminary assessment of western Pacific 

 yellowfin tuna exploited by the longline fishery (Honma and Suzuki, see 

 footnote 2) was presented at the tuna and bill fish stock assessment 

 workshop held at Shimizu, Japan, in June 1979. Since that time there has 

 been no concerted effort to continue these studies. 



