. The Eastern Bering Sea Shelf : oceanography and resources / edited by Donald W. Hood and John A. Calder . Copepods Figure 33-18. Apparent food web based upon pollock in the eastern Bering Sea. Dotted lines indicate pollock ontogeny. Solid lines show important feeding relationships, with arrowheads and line weights indicating the direction and relative magnitude of carbon flows. dominant long-term mean circulation is an extremely slow (1 cm/sec) drift to the northwest approximately parallel to the bathymetry (Coachman 1979). If spawning occurs predominantly along the southeast outer shelf, th
. The Eastern Bering Sea Shelf : oceanography and resources / edited by Donald W. Hood and John A. Calder . Copepods Figure 33-18. Apparent food web based upon pollock in the eastern Bering Sea. Dotted lines indicate pollock ontogeny. Solid lines show important feeding relationships, with arrowheads and line weights indicating the direction and relative magnitude of carbon flows. dominant long-term mean circulation is an extremely slow (1 cm/sec) drift to the northwest approximately parallel to the bathymetry (Coachman 1979). If spawning occurs predominantly along the southeast outer shelf, then several months of north- west drift would carry larvae to the vicinity of the Pribilof Islands. In fact, during NMFS Crab-Ground- fish trawl surveys conducted from June to mid- August, 0-group pollock (approximately two to four months old, and 35-80 mm fork length) have been observed over a large area of the northwestern outer shelf (Fig. 33-16). Highest concentrations of 0-group juveniles, showing as dense mid water or near-bottom layers, have been noted directly west of the Pribilof Islands. Inspections of the stomach contents of demersal fish species throughout the eastern conti- nental shelf region have found 0-group pollock (lengths 50-80 mm) to occur as an abundant food item only in this same area. By one year of age, pollock are broadly distri- buted over the entire central and outer continental shelf, completely overlapping and extending inshore beyond the adult range (Fig. 33-17). By two years of age, pollock remain more restricted to deep water, and with growth, begin to recruit to the trawl fisher- ies. FOOD-WEB RELATIONSHIPS One of the most striking features of the eastern Bering Sea food web is the extent to which pollock are represented in feeding relationships and overall energy exchange (Fig. 33-18). During different life history stages, pollock feed upon a broad spec- trum of prey (Takahashi and Yamaguchi 1972, Mito 1974, Clarke 1978, Feder 1978, Smith et al
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