554 



Fishery Bulletin 97(3), 1999 



erage out" and thus would vary less than the range 

 of capture rates for schools. On the other hand, dif- 

 ferences between schools in factors other than size 

 could lead to short-term individual capture rates that 

 are even higher than our estimates. 



Acknowledgments 



^ We thank M, Hall, M. Garcia, C. Lennert, and M. 

 Scott of the Inter- American Tropical Tuna Commis- 

 sion, and W. Armstrong, J. Barlow, R. Holt, A. Jack- 

 son, R. Rasmussen, and K. Wallace of the SWFSC, 

 for the benefit of their field experience and their tech- 

 nical knowledge of the tuna vessel obser\'er program, 

 the NMFS research cruises, and the related data- 

 bases. Special thanks to T. Gerrodette of the SWFSC 

 and D. Palka of the NEFSC for theoretical and prac- 

 tical advice on the bivariate hazard rate model. We 

 also thank J. Barlow, B. Curry, T Gerrodette, M. Hall, 

 P. Kleiber, and two anonymous reviewers for their 

 comments on draft versions. Finally, we gratefully 

 acknowledge all of the scientists, observers, NOAA 

 officers and crew, and fishermen who participated in 

 the collection of the research vessel observer data 

 and the tuna vessel observer data. 



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