HANAN: BLUEFIN TUNA FISHERY 

 2.80 



2.10 



UJ 



Q. 

 O 



1.40 



0.70 



1960 1964 



1968 1972 

 YEAR 



1976 1980 



FIGURE 19.— Annual Japanese catch per unit effort (metric 

 tons/boat-day) from long-line catches of northern bluefin tuna 

 for the years 1962-79. 



Although those data (Anonymous 1981; Yama- 

 naka and Staff 1963) represent only a portion oi 

 the fishing effort in the western Pacific, they in- 

 dicate a need for more extensive and explicit 

 data from that area. With improved data, mathe- 

 matical models for estimating sustainable yields 

 can be used to describe the status of the bluefin 

 resource throughout the North Pacific Ocean. 



Based on strong evidence of declining stock 

 abundance, the bluefin tuna fisheries in the Pa- 

 cific Ocean should receive an extensive analyti- 

 cal review, and nations fishing bluefin, especially 

 Japan, Mexico, and the United States, should 

 consider needed actions. If management to con- 

 serve this valuable resource is to be taken, it 

 should be soon, so that the resource can return to 

 an optimal level of abundance. 



ACKNOWLEDGMENTS 



I sincerely thank Alec MacCall (CFG) for his 

 help and recommendations during this study. 

 Norman Bartoo (NMFS) provided valuable ad- 

 vice in the preparation of the manuscript. The 

 editorial reviewers, especially Harold Clemens 

 (CFG) and William Bayliff (IATTC), are thanked 

 for their comments and suggestions. Funds for 

 the study were provided by contract to the South- 

 west Fisheries Center, NMFS. 



LITERATURE CITED 



Anonymous. 



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 Bayliff, W. H. 



1980. Synopsis of biological data on the northern bluefin 

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 261-294. 

 Bayliff, W. H., and T. P. Calkins. 



1979. Information pertinent to stock assessment of north- 

 ern bluefin tuna, Thunnus thynnus, in the Pacific Ocean. 

 Inter-Am. Trop. Tuna Comm., Intern. Rep. 12, 78 p. 

 Beauchamp, J. J., and J. S. Olson. 



1973. Corrections for bias in regression estimates after 

 logarithmic transformation. Ecology 54:1403-1407. 

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1965. An analysis of California's albacore fishery. Calif. 

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1969. Bluefin tuna migrate across the Pacific Ocean. 

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GULLAND, J. A. 



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 experiments. Int. Comm. Northwest Atl. Fish., Spec. 

 Publ. 4:218-227. 

 PELLA, J. J., AND C. T. PSAROPULOS. 



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 RlCKER, W. E. 



1975. Computation and interpretation of biological sta- 

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SCHULTZE, D. L., AND R. A. COLLINS. 



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 Whitehead, S. S. 



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