Winter A S CALIF 





Seasonal Depth Distribution of Pacific Whiting 



+ "o^*" 



Figure 19.- 



-Seasonal depth distribution of Pacific whiting (from Alverson and 

 Larkins 1969). 



Figure 20. — Locations off California where 326 northern fur seals were collected 

 whose stomachs contained market squid, 1958-66. 



lections made during January, March, April, and June (Fig. 

 7). Its occurrence in stomachs of fur seals is shown in Figure 

 20. Among the eight taxa of squids identified in stomachs of 

 fur seals taken off California, the market squid and oceanic 

 squids, Onychoteuthis sp. and O. borealijaponicus, were iden- 

 tified most frequently. 



The market squid population is considered to be large as are 

 most cephalopod populations in the eastern North Pacific 

 Ocean. Although the life history of the market squid is rela- 

 tively well known (Fields 1965), the life histories of other 

 pelagic cephalopod fauna of the eastern North Pacific Ocean 

 are poorly known. 



Based on CalCOFI surveys, the market squid ranked third 

 among cephalopods in abundance (Okutani and McGowan 

 1969). Squid larvae found in greatest abundance were Abrali- 

 opsis felis and Gonatus fabricii. Abraliopsis sp. and Gonatus 

 spp. were also consumed by fur seals taken off California. 

 These species of squids normally inhabit the epi- and meso- 

 pelagic zones seaward of the continental shelf waters. 



The market squid is neritic, being found over the continental 

 shelf and in coastal waters but very seldom over deep water. 

 The known geographic range of the market squid is from 

 Hecate Strait, British Columbia, into Puget Sound, Washing- 

 ton, and south to Guadalupe Island and Turtle Bay, Mexico 

 (Berry 1912; Okutani and McGowan 1969). A few occurrences 

 of this species have been identified in stomachs of fur seals 

 taken in the Gulf of Alaska in 1958 and 1962. 



Studies of the feeding habits of the market squid in Mon- 

 terey Bay show changes in diet with location and depth but 

 with no changes with respect to size of squid or sex. Squids 

 were found to be feeding primarily on euphausiids, copepods, 

 megalops larvae, mysids, and amphipods as well as on fish and 

 other cephalopods (Karpov and Cailliet 1979). Cannibalism is 

 common among squids in the pelagic environment and the 

 mature squids probably feed exclusively on fishes and cephalo- 

 pods. 



Most pelagic marine mammals feed to varying degrees on 

 squids which are available in the epi- and mesopelagic zones 

 whereas some of the deep diving mammals, such as the sperm 

 whales, have diets which consist of 90% squids from the 

 greater ocean depths. Laevastu and Fiscus (1978)" conserva- 

 tively estimated the annual consumption of squids by the 

 North Pacific sperm whales to be about 30 million tons and 

 estimated 220 million tons of squids being consumed annually 

 by all predators in the North Pacific marine ecosystem. Clarke 

 (1977) estimated the worldwide squid consumption by sperm 

 whales to be about 320 million tons. Okutani (1977) reported 

 worldwide squid species (including cuttlefish) numbering be- 

 tween 450 to 500 species belonging to 30 families. 



"Laevastu, T., and C. H. Fiscus. 1978. Review of cephalopod resources in the 

 eastern North Pacific. Processed rep., 15 p. Northwest and Alaska Fish. Cent., 

 Natl. Mar. Fish. Serv., NOAA, 2725 Montlake Blvd. E., Seattle, WA 98112. 



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