. The Eastern Bering Sea Shelf : oceanography and resources / edited by Donald W. Hood and John A. Calder . Figure 33-6. Temperature and salinity ciiaracteristics of the environment of walleye pollock in the eastern Bering Sea (shaded area). Pollock T-S data replotted from Kihara and Uda (1969); North Pacific Ocean water mass data are from Sverdrup et al. (1946). in the eastern Bering Sea, then, is a broad section of the outer continental shelf and slope primarily within the 100-300 m depth range. The bottom morphology of the continental shelf in most of this region is featureless and level, w
. The Eastern Bering Sea Shelf : oceanography and resources / edited by Donald W. Hood and John A. Calder . Figure 33-6. Temperature and salinity ciiaracteristics of the environment of walleye pollock in the eastern Bering Sea (shaded area). Pollock T-S data replotted from Kihara and Uda (1969); North Pacific Ocean water mass data are from Sverdrup et al. (1946). in the eastern Bering Sea, then, is a broad section of the outer continental shelf and slope primarily within the 100-300 m depth range. The bottom morphology of the continental shelf in most of this region is featureless and level, with sand and silt surface sediments (Sharma 1974). In deeper water, the continental margin is steep and cut by large sub- marine canyons that substantially affect the flow and mixing of water currents along the shelf edge (Kinder etal. 1975). In comparison to temperature and salinity charac- teristics of water masses in other regions of the North Pacific Ocean, pollock occur within a relatively extreme seawater environment in the eastern Bering Sea (Fig. 33-6). These distinctive conditions—cold and low salinity—result from mixing of shelf and oceanic waters within apparently broad zones of interaction along and over the eastern continental shelf (Takenouti and Ohtani 1974, Coachman and Charnell 1979). Source waters, mixing characteris- tics, and associated hydrographic features must all be important in determining the composition of both pollock prey and predators. Stock size Seven well-documented estimates of the absolute Bering Sea pollock are A confusing feature of bulk biomass of eastern summarized in Table 33-1 these results is the use of different, and sometimes unspecified, geographical boundaries among the different analyses. In addition, because all of the estimates are based upon selective sampling (namely, demersal trawl nets, and in the case of estimates based upon commercial data, targeted fisheries), the relationships between statistical populations included i
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