The leading four prey species consumed by fur seals during 

 the six collection years off California contributed 82 to 99% of 

 the total stomach content volume. From a total of 26 species 

 of fish and 8 species of squid identified in stomachs of fur seals 

 taken off California, only 6 species of fish and 2 species of 

 squid are considered the principal prey of fur seals in this area. 

 These principal forage species included northern anchovy, 

 Pacific whiting, the market squid, Pacific saury, jack mack- 

 erel, rockfishes, sablefish, and the oceanic squid, Onychoteu- 

 this sp. The first three species were among the four leading for- 

 age species during every monthly collection off California. 



Similarly for the Bering Sea, the principal prey species con- 

 tributed 75 to 99% of the total stomach content volume during 

 the seven collection years. From a total of 23 species of fish 

 and 3 species of squid identified in stomachs of fur seals taken 

 in the Bering Sea, only 5 species of fish and the 3 species of 

 squid were considered the principal prey of fur seals in this 

 area. These principal forage species included walleye pollock; 

 capelin; Atka mackerel; oceanic squids Gonatus spp., Berry- 

 teuthis magister, and Gonatopsis borealis; and Pacific herring. 

 Deepsea smelt of the family Bathylagidae and salmon were 

 among the principal forage species during annual collections 

 but not when all years' data were combined by month for the 

 Bering Sea. Salmon occurred among the principal forage food 

 of fur seals in 1960 and deepsea smelt in 1963, 1968, 1973, and 

 1974. Greenland turbot was important in 1973. 



Off Oregon, the collections of fur seals were relatively small 

 as seals were collected while vessels were enroute between 

 Washington and California. Of the 14 species of fish and 7 

 species of squid identified in stomachs of fur seals taken in this 

 area, Pacific whiting, rockfish, northern anchovy, and squids 

 were the principal foods. 



Off Washington, the principal forage species contributed 64 

 to 99% of the total food volume. From a total of 33 species of 

 fish and 10 species of squid identified in stomachs of fur seals 

 taken in this area, only 8 species of fish and 1 species of oce- 

 anic squid were considered the principal prey of fur seals. The 

 principal prey species included Pacific herring, rockfish, 

 northern anchovy, capelin, eulachon, salmon, Pacific whiting, 

 sablefish, and squid, Onychoteuthis sp. 



Off British Columbia, the principal prey species contributed 

 66 to 95% of the total food volume. From a total of 15 species 

 of fish and 4 species of squid identified in stomachs of fur seals 

 taken in this area, 9 species of fish, the market squid, and the 

 oceanic squid were considered the principal prey of fur seals 

 off British Columbia. The principal forage species included 

 Pacific herring; eulachon; salmon; squids, Loligo opalescens 

 and O. borealijaponicus; sablefish; rockfish; walleye pollock; 

 Pacific cod; Pacific whiting; and Pacific saury. 



In the Gulf of Alaska, the principal prey species contributed 

 89 to 99% of the total food volume. From a total of 21 species 

 of fish and 5 species of squid identified in stomachs of fur seals 

 taken in this area, 7 species of fish including Pacific sand 

 lance, capelin, Pacific herring, walleye pollock, Atka mack- 

 erel, rockfish, and salmon were the principal fishes while 

 Gonatus spp. and B. magister were the principal squids. 



In the western Alaska region, principal prey species contrib- 

 uted 77 to 99% of the total food volume. From the 19 species 

 of fish and 3 species of squid identified in stomachs of fur seals 

 taken in this area, 7 species of fish and 1 species of squid 

 ranked as principal prey. The principal forage species included 



Pacific sand lance; capelin; squid, B. magister, Atka mackerel; 

 walleye pollock; Pacific salmon; Pacific herring; and sablefish. 



The major fish-squid resources as related to the principal 

 forage species of fur seals off California and in the Bering Sea 

 were discussed and included the known distribution, abun- 

 dance, and migratory movements for each prey species as an 

 aid in understanding the feeding habits of fur seals. In addi- 

 tion the principal forage species of fur seals off Washington, 

 British Columbia, the Gulf of Alaska, and western Alaska 

 were briefly discussed. 



The major fish-squid resources off California (as deter- 

 mined from bottom trawl, midwater hydroacoustical, and 

 CalCOFI surveys) in order of relative abundance are 1) north- 

 ern anchovy, 2) Pacific whiting, 3) rockfishes, 4) jack mack- 

 erel, 5) Pacific saury, and 6) market squid. 



The northern anchovy was the most abundant, and the larg- 

 est fishery resource in the California Current System followed 

 by the Pacific whiting which consistently ranked second to an- 

 chovy in annual estimates of relative abundance in the area 

 surveyed. Although there was no estimate of rockfish biomass, 

 it is known in general terms to be large. The jack mackerel, 

 which is of widespread occurrence off California, was second 

 only to the anchovy in frequency of occurrence in midwater 

 trawl catches. Pacific saury was considered to be the fifth most 

 abundant species as determined from CalCOFI surveys. The 

 market squid, found over the continental shelf, was reported 

 as probably the most abundant squid off the California coast. 



The rank order by frequency of occurrence (%) of the 20 

 most common fish taxa in the eastern Bering Sea trawl catches 

 included four principal forage species of fur seals. In order 

 these are: First, walleye pollock (occurring in 91% of the sta- 

 tions fished); second, Greenland turbot (occurring in 78% of 

 the stations fished); eleventh, Pacific herring (occurring in 

 37% of the stations fished); and seventeenth, capelin (occur- 

 ring in 22% of the stations fished). The principal forage 

 species of fur seals not among the trawl catches included Atka 

 mackerel, Pacific sand lance, deepsea smelt, salmon, and 

 oceanic squids. 



Based on the principal prey species of fur seals (as deter- 

 mined from stomach contents) and the relative abundance of 

 the fish-squid resources off California and the eastern Bering 

 Sea (based on ocean surveys), we must conclude that fur seals 

 are opportunistic feeders, foraging on the most abundant fish- 

 squid species available to fur seals in an area. Opportunistic 

 feeding by fur seals on the most abundant and available spe- 

 cies prevails throughout their range in the eastern North 

 Pacific Ocean and eastern Bering Sea. 



NOTE ADDED IN PRESS 



The 1983 Draft Environmental Impact Statement (DEIS) on 

 the Interim Convention on Conservation of North Pacific Fur 

 Seals 24 shows a decline in the Pribilof and Robben Island pop- 

 ulations of fur seals to 975,000 and 84,000, respectively. The 

 Commander Islands (325,000), Kurile Islands (54,000), and 

 San Miguel Island (4,000) all show population increases. 



"National Marine Fisheries Service. In Prep. Draft Environmental Impact 

 Statement on the Interim Convention on Conservation of North Pacific Fur 

 Seals. U.S. Dep. Commer., NOAA, NMFS, Wash., D.C. 



32 



