FISHERY BULLETIN: VOL. 70, NO. 3 



of fish schools based on numerical integration 

 can be verified by drifting buoys and by follow- 

 ing fish tagged with a sonic device. 



The experimental approach will also aid to 

 answer such questions as the following: Why 

 is there little evidence of spawning between the 

 eastern North Pacific and long 140° W? Why are 

 skipjack schools not evident at the sea surface? 

 Is the productivity of the water adequate to sup- 

 port the skipjack schools with a slow net move- 

 ment? What is the eflFect of varying forage 

 abundance on the search pattern and therefore 

 the dispersion of skipjack schools? 



The implications of an experimental, numeri- 

 cal approach to the skipjack distribution problem 

 are far-reaching. The principal results of the 

 simple drift model used in this paper will hold 

 in a more sophisticated model where observed 

 rather than climatic boundary conditions are 

 used. The results indicate that the probable 

 drift path and concentration of skipjack schools 

 is predictable. Such predictions will increase 

 the harvest efficiency of the skipjack resource. 

 The insight gained into the life history of skip- 

 jack, particularly if the survival mechanisms 

 of early life stages are included in the model, 

 will permit elegant management of the skipjack 

 resource. 



ACKNOWLEDGMENTS 



I wish to thank Kevin Rabe, Naval Environ- 

 mental Prediction Research Facility, for pro- 

 gramming the drift model, and Drs. Taivo Lae- 

 vastu, Naval Environmental Prediction Re- 

 search Facility, and F. Williams, Scripps Insti- 

 tution of Oceanography, for reviewing the man- 

 uscript. 



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