Goebel et al Diving patterns and foraging locations of female Callorhmus ursinus 



179 



Before the advent of dive-recording instruments, one 

 of the most important measurements used to assess 

 changes in prey availability for pinnipeds and sea birds 

 was the length of foraging trips. Foraging trips, how- 

 ever, may be useful only in documenting large-scale 

 changes in prey availability (e.g., El Nino events). Dive- 

 recorder instruments provide the opportunity to 

 measure changes in the foraging environment on a 

 finer scale. This work underscores the importance of 

 quantifying dive patterns in elucidating differences in 

 foraging strategies and in changes in the foraging 

 environment. 



Acknowledgments 



We wish to thank the following people for their gen- 

 erous assistance in the field: P. Dawson, H. Kajimura, 

 R. Merrick, Y. Nomura, and K. Yoshida. Special thanks 

 are extended to R. Merrick, who was instrumental dur- 

 ing the aerial tracking of animals at sea, and C. Fish, 

 the pilot during aerial surveys. We thank the follow- 

 ing for their valuable comments on the manuscript: 

 G. Antonelis, H. Huber, L. Jones, W. Roberts, E. Sin- 

 clair, and A. York. 



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