Title: The Eastern Bering Sea Shelf : oceanography and resources / edited by Donald W. Hood and John A. Calder
Identifier: easternberings00hood (find matches)
Year: 1981 (1980s)
Authors: Hood, D. W. (Donald Wilbur), 1918-; Calder, John A; United States. Office of Marine Pollution Assessment; United States. Bureau of Land Management
Subjects: Oceanography Bering Sea.
Publisher: (Rockville, Md. ?) : U. S. Dept. of Commerce, National Oceanic and Atmospheric Administration, Office of Marine Pollution Assessment ; Seattle, Wash. : Distributed by the University of Washington Press
Contributing Library: Penn State University
Digitizing Sponsor: LYRASIS Members and Sloan Foundation

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510 Fisheries oceanography observed in the frequencies of eight genes (S. Grant, Northwest and Alaska Fisheries Center, Seattle, Washington, personal communication). Svetovidov (1952) believes that Pacific herring arrived from the Atlantic some time between the Pliocene and the "post-glacial 'transgression' " via the Asian Arctic. Pacific herring also differ from Atlantic herring in spawning and migrational behavior: the former are spring spaviTiers, whereas the latter may be spring, winter, summer, or autumn spawners. Pacific herring spawn between the intertidal zone and about 20 m and deposit eggs on vegetation, whereas Atlantic herring spawn in deep water on a gravel bottom. Pacific herring generally remain near the spawning ground the year round and do not make extensive seasonal migrations as many Atlantic stocks do. In the North Pacific Ocean, herring are distributed along the Asiatic and North American continental shelves (Fig. 32-1); in Asia they range from Taksi Bay, near the mouth of the Lena River, to the Yellow Sea (Andriyashev 1954), and in North America from Cape Bathurst in the Beaufort Sea to San Diego Bay, California (Hart 1973). Herring are an important part of the eastern Bering Sea food web. They are pelagic planktivores, highly adapted with large mouths and numerous fine giU rakes for efficient utilization of euphausiids, cope- pods, and other zooplankton. In turn, herring are important prey for marine mammals, birds, and roundfish. Mathematical simulations of the eco- system in this area by Laevastu and Favorite (1978) indicate that annual total mortality amounts to one half of herring biomass production and that 95 percent of total mortality is by predation. Given this level of mortality, it is understandable that herring stocks exhibit strong fluctuations in abundance with apparently small changes in fishing or environmental factors. The abundance of herring declined sharply in the early 1970's and only recently has an increase be- come apparent. Although several hypotheses could be advanced to explain the strong population fluctua- tions observed, data are insufficient to conclusively establish a cause. Since rapid, marked changes in abundance are expected to occur in the future, it will be necessary to be able to identify the causes and predict their occurrence and magnitude. Present knowledge is rudimentary and inferences
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Figure 32-1. Geographic range of Pacific herring (Clupea harenguspallasi) in the North Pacific Ocean.

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