Winship and Trites: Prey consumption of Eumetopias /ubatus 



161 



siderable uncertainty associated with them. Thus, the 

 management apphcations of our findings are limited by 

 the quahty of data currently available for Steller sea lions. 

 Nevertheless, our estimates of consumption shed light on 

 the trophic relationships between Steller sea lions and 

 their prey and provide insights into possible relation- 

 ships between food consumption and differential rates of 

 population decline in different regions of Alaska. As more 

 detailed diet information becomes available for Steller sea 

 lions in Alaska, our model can be used to provide more 

 refined estimates of prey consumption that can be incor- 

 porated in prey stock assessments and management deci- 

 sions (e.g. Hollowed et al., 2000). 



Acknowledgments 



We thank D. A. S. Rosen for sharing his data on digestive 

 efficiency and heat increment of feeding with us. We also 

 thank I. L. Boyd, V. Christensen, S. Cox, W. K. Milsom, D. 

 Pauly, D. A. S. Rosen, D. J. Tollit, and C. J. Walters for helpful 

 comments and criticism on the study and earlier drafts of 

 this manuscript. We appreciate the constructive comments 

 and suggestions of M. K. Alonso and an anonymous jour- 

 nal reviewer which improved our manuscript. We are also 

 grateful for the administrative support of Pamela Rosen- 

 baum. Financial support was provided to the North Pacific 

 Universities Marine Mammal Research Consortium by the 

 U.S. National Oceanographic and Atmospheric Adminis- 

 tration through the North Pacific Marine Science Founda- 

 tion. Financial support also was provided by the Natural 

 Sciences and Engineering Research Council (Canada) in 

 the form of a postgraduate scholarship to AJW. 



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