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surface fishery increased, the gains were not enough to offset the 

 decreases in Y/R for the longline and North American surface fisheries. 

 The analyses predicted that gains in Y/R were possible through increased 

 effort on larger fish. Y/R isopleths for the Japanese surface, Japanese 

 longline, and North American surface fishery are shown in Figures 7, 8, and 

 9, respectively. 



III.B.4. Results of Spawner/Recruitment Analysis 



No satisfactory spawner/recruit relationship has been 

 established. Previous analyses have failed to develop appropriate indices 

 of spawner and recruit abundance. 



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



Additional analyses have shown very poor correlation 

 between indices of abundance among the three major fisheries, even when 

 annual age specific catch rates were used. 



III.C. Current Evaluation of Stocks and the Fishery 



At present North Pacific albacore are being fished at effort levels 

 below those that permit harvest at MSAY. Modest gains in Y/R are possible 

 through increased effort on older fish, but substantial increases are 

 unlikely given the present patterns of fishing. There is currently no 

 evidence to indicate a depletion of the adult (spawner) stock. 



IV. STATUS OF CURRENT RESEARCH NEEDS AND EFFORT 

 IV. A. Major Research Problems 



The most immediate research needs include: 1) Development of non- 

 effort based assessment methods to augment the existing analytical models; 

 2) validation of currently accepted growth rate of North Pacific albacore, 

 which are determined from daily otolith increments using a newly developed 

 fin ray technique; 3) re-examination of the population dynamics of the 

 stock in the light of recent and future improvements in parameter 

 estimation; 4) investigation of stock structure through differences in 

 bio-chemical information among fish from different areas, through the study 

 of oceanic phenomena that might explain stock separation and through the 

 development of a model to test various stock structure hypotheses; and 5) 

 the identification and quantification of environmental variables for input 

 into an environmental simulation model designed to explain variability in 

 catch levels and catch rates, among and within the major fisheries. 



