FISHERY BULLETIN: VOL. 84, NO. 4 



used in analyses of pelagic data for northern fur 

 seals. The subregions were selected to compare diet 

 between inshore (neritic) and offshore (oceanic) 

 areas and to indicate diet in certain localities where 

 collection effort was relatively high. Inshore areas 

 were defined as those generally occurring on the 

 continental shelf (depths up to 100 fathoms) and off- 

 shore areas as those beyond the continental shelf. 



RESULTS 



The cruise tracks (Fig. 2) taken by research 

 vessels of the United States and Canada for the col- 

 lection of northern fur seals during 1958-74 indicate 

 the relative distribution of research effort. Most col- 

 lections were made in the coastal areas between 

 California and British Columbia, off Kodiak Island, 

 and in the eastern Bering Sea between Unimak Pass 

 and the Pribilof Islands. Few specimens were taken 

 more than 160 km from shore. 



Diet by Region and Month 



An examination of the number of prey species that 

 made up the diet indicates that at least nine species 

 may be consumed within any one subregion. How- 

 ever, typically only three prey species made up about 

 80% of the diet (Fig. 3). Thus, relatively few species 

 of food are of primary importance in any one local- 

 ity. As will be made clear in the following regional 

 and subregional accounts, the primary food species 

 can change among localities. 



Our interpretation of Figures 4-11 which follow 

 requires clarification. These figures show modified 

 volume values only for those individual species that 

 we felt were important and that had sufficient 

 sample sizes to be reliable. Thus, we arbitrarily pre- 

 sented only those species that were of >5% in im- 

 portance for samples with at least 20 stomachs con- 

 taining food. Species of less importance were pooled 

 either as miscellaneous fishes or squids. Also, be- 



62° N 



175° W 155° 135° 115° 



Figure 2.— Cruise tracks of northern fur seal research vessels from the United States and Canada during 1958-74. 



960 



