1970 and 1972 (Marine Mammal Biological Laboratory 1971*; 

 Fiscus et al. 1973 7 ). This information does not show in pooled 

 data (combined years) because these data are generally con- 

 cealed by the more abundant (dominant) species over the com- 

 bined years of collection. 



Because of such circumstances, the locality and time of col- 

 lection dictate to a great degree the occurrence of certain prey 

 species in the stomachs of fur seals. Consequently knowledge 

 of the oceanographic conditions in the collection area, as 

 related to time and seasonal movements of prey, is needed as 

 an aid in understanding the feeding habits of fur seals. The 

 dominant food of fur seals collected seaward of the continen- 

 tal shelf over deep water is usually oceanic squids (squids and 

 deepsea smelt in the Bering Sea) while nearshore collections 

 made over the shelf indicate fish as the primary food — the ex- 

 ception being the neritic market squid, Loligo opalescens, 

 which is usually found over the continental shelf and in coastal 

 waters and seldom over deep water. Some principal prey spe- 



cies that are important during yearly collections are not evident 

 when samples are combined over many years of collection. 

 Caution must be exercised in examining data on stomach 

 contents of fur seals during the early years of pelagic research 

 (1958-63). During these years an annual and relatively high 

 quota for the collection of fur seals was in effect which more 

 or less dictated intensive sampling in areas where seals concen- 

 trated. As a result, when concentrations of seals were encoun- 

 tered, as many animals as possible were collected to achieve 

 annual research quotas. Examination of stomach contents 

 usually revealed that seals from one locality were feeding on 

 the same prey. Collections of large numbers of seals from one 

 area may thus bias the importance of a particular prey species 

 in that area (i.e., off California) for the season. It must be 

 recognized that the time spent collecting samples in one local- 

 ity precluded collecting seals on predetermined random tran- 

 sects to obtain representative samples. The locations of fur 

 seals collected off California and in the eastern Bering Sea are 

 shown in Figures 4 and 5. 



'Marine Mammal Biological Laboratory. 1971. Fur seal investigations. 1970. 

 Unpubl. manuscr., 155 p. Natl. Mar. Mammal Lab., Northwest and Alaska Fish. 

 Cent., Natl. Mar. Fish. Serv., NOAA, 7600 Sand Point Way NE., Seattle, WA 

 98115. 



'Fiscus, C. H., H. Kajimura, and A. A. Wolman. 1973. Part II. Pelagic fur seal 

 investigations, 1972. In Marine Mammal Division, Fur seal investigations, 1972, p. 

 29^7, 67-91. Unpubl. rep. U.S. Dep. Commer., NOAA, Natl. Mar. Fish. Serv., 

 Northwest Fish. Cent., Seattle, Wash. (Avail. Natl. Mar. Mammal Lab., North- 

 west and Alaska Fish. Cent., Natl. Mar. Fish. Serv., NOAA, 7600 Sand Point Way 

 NE., Seattle. WA 981 15.) 



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Figure 4. — Locations off California where 3,613 northern fur seals were collected, 

 1958-66. 



167 165 



Figure 5. — Locations in the eastern Bering Sea where 4,659 northern fur seals were 

 collected, 1958-74. 



FISHERY RESOURCES SIGNIFICANT 

 TO FUR SEALS 



Figure 6 illustrates the seven areas into which the eastern 

 North Pacific region was divided for the purpose of conduc- 

 ting the dietary studies reported here. For the areas shown in 

 Figure 6, the boundaries (in parentheses) are as follows: Cali- 

 fornia (lat. 32° to 42°N); Oregon (lat. 42° to 46°N); Washing- 

 ton (lat. 46° to 49°N); British Columbia (lat. 49° to 54°30 'N, 

 long. 146 °W); Gulf of Alaska (lat. 54°30 'N to coast and long. 

 158°W, and lat. 49° to 54°30'N between long. 146° and 

 158°W); western Alaska (west of long. 158°W and north of 

 lat. 49°N, and north to the Alaska Peninsula and Aleutian Is- 

 lands); eastern Bering Sea (north of the Alaska Peninsula and 

 Aleutian Islands). 



The list of fishes and squids consumed by fur seals through- 

 out their range in the eastern North Pacific Ocean and in the 

 eastern Bering Sea is shown in Tables 1 and 2. The principal 

 prey species of fur seals in each of these areas as based on 



