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Nor/hern Subpopulotioo 



Central Subpopulot/on 



WINTER 

 S 



SPRING 



WINTER . 



a 



SPRING 













ANCHOVY BIOMASS 





1/1 









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1955 1960 1965 



Figure 17.— The distribution of anchovy subpopulations (from Huppert et al. 

 1980) and total spawning biomass (from Vrooman and Smith 1971). 



chovies at the surface and, when approached, fur seals or 

 other marine mammals were usually found. Pacific whiteside 

 dolphins and Dall's porpoise, Phocoenoides dalli, collected 

 off California were also feeding on anchovy, Pacific whiting, 

 Pacific saury, and a variety of squids (Kajimura et al. 1980). 

 Rice (1977) reported northern anchovy as the dominant food 

 of sei whales, Balaenoptera borealis, off California during 

 June, July, and August. Rice also reported that anchovies oc- 

 curred in 7% of the stomachs of fin whales, Balaenoptera 

 physalus, and 60% of the stomachs of humpback whales, 

 Megaptera novaeangliae. Although sperm whales, Physeter 

 macrocephalus, are year-round residents off California, they 

 apparently do not feed on anchovies as large forage species ap- 

 pear to be more to their liking, especially larger oceanic squids 

 (Rice and Wolman 1970'°). 



Pacific whiting. — Pacific whiting has been among the lead- 

 ing forage species consumed by fur seals off California during 

 April and May and second in importance during January, Feb- 

 ruary, and March (Fig. 7). All months combined, whiting was 

 second only to northern anchovy as the leading forage species 

 consumed by fur seals off California. The geographic occur- 

 rence of whiting in stomachs of fur seals is shown in Figure 18. 



Pacific whiting is a schooling fish that is distributed over the 

 continental shelf and slope from the Gulf of California to the 

 Gulf of Alaska. Egg and larval studies by CalCOFI also indi- 

 cate that whiting is consistently ranked second to anchovy in 

 annual estimates of relative abundance in the survey area (Ahl- 

 strom 1969). Spawning occurs primarily during winter and 

 early spring (December to April) in deepwater areas along the 

 coasts of southern California and Baja California, Mexico. 

 The whiting undertakes an annual migration northward in the 

 spring and summer and southward beginning in autumn (Fig. 



l0 Rice, D. W., and A. A. Wolman. 1970. Sperm whales in the eastern North 

 Pacific: Progress report on research, 1959-69. Submitted to Scientific Committee, 

 sperm whale biology and stock assessment meeting, Honolulu, Hawaii, Doc. 

 Sp/3., 18 p. (Avail. Natl. Mar. Mammal Lab., Northwest and Alaska Fish. Cent., 

 Natl. Mar. Fish. Serv., NOAA, 7600 Sand Point Way NE., Seattle, WA 98115.) 



•t I 





1 1 \ 





Jft •TEurvV.i 





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* V 



£■• 



* * * V. 



V 





< 







* 1 



O 





•s- 



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-9 



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S San Francisco 



fjl 





**/*.♦ ♦♦ 







+** ** 



> ; * X 



• +** 



* *** >l 



< 







.. .*»* V 









+ + * +* * L. Pi. Conception 





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♦♦ ***. -o^ 





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Figure 18.— Locations off California where 658 northern fur seals were collected 

 whose stomachs contained Pacific whiting, 1958-66. 



19). It is during this period, when feeding fish are over the con- 

 tinental shelf and slope, that the whiting is subjected to the 

 foreign fishery. Although there is no major U.S. fishery for 

 whiting off the western coast of North America, the species 

 has been the subject of an intensive foreign fishery in this area 

 since 1966. Dark et al. (1980) estimated the total whiting bio- 

 mass at about 1.2 million tons (average annual foreign commer- 

 cial catch of 167,000 tons) based on bottom trawl and midwater 

 hydroacoustical trawl surveys conducted during July-September 

 1977. This survey also indicated the whiting biomass is nearly 

 evenly distributed over fishing areas known as the Vancouver, 

 Columbia, and Eureka grounds and less abundant to the south 

 over the Monterey and Conception grounds. 



Pacific whiting, which are cannibalistic, make pronounced 

 diel vertical migrations to feed on anchovy, rockfish, and 

 market squid. Fiscus (1979) summarized the known or sus- 

 pected marine mammals and other predators which forage on 

 whiting. 



Market squid. — The market squid is an important forage 

 food of many fishes, seabirds, and marine mammals and is an 

 important link between zooplankton and the higher trophic 

 levels in the pelagic environment of the California Current Sys- 

 tem (Fig. 15). Young (1972) reported that the market squid is 

 probably the most abundant squid off the California coast. 

 The market squid (a schooling species) is one of the leading 

 forage species of the fur seal off California as evidenced in col- 



16 



