. The Eastern Bering Sea Shelf : oceanography and resources / edited by Donald W. Hood and John A. Calder. Oceanography Bering 516 Fisheries oceanography Akimova (1972) found that juvenile herring con- sumed small and medium forms of zooplankton (chaetognaths, copepods, tunicates) and bentho- plankton (mysids). Euphausiids, amphipods, mol- lusks, and other organisms were found rarely, and usually in small quantities. In the demersal zone, herring stomachs contained quantities of tubes of polychaete worms, bivalve moUusks, amphipods, copepods, juvenile fish, and detritus. In the eastern B
. The Eastern Bering Sea Shelf : oceanography and resources / edited by Donald W. Hood and John A. Calder. Oceanography Bering 516 Fisheries oceanography Akimova (1972) found that juvenile herring con- sumed small and medium forms of zooplankton (chaetognaths, copepods, tunicates) and bentho- plankton (mysids). Euphausiids, amphipods, mol- lusks, and other organisms were found rarely, and usually in small quantities. In the demersal zone, herring stomachs contained quantities of tubes of polychaete worms, bivalve moUusks, amphipods, copepods, juvenile fish, and detritus. In the eastern Bering Sea, stomachs in August were 84 percent filled with euphausiids, 8 percent with fish fry, 6 percent with calanoids, and 2 percent with gammarids (Rumyantsev and Darda 1970). Fish fry, in order of importance, were walleye pollock, smelt, capelin, and sand lance. In spring, food was mainly Themisto (Amphipoda) and Sagitta (Chaetognatha). After spawning, the main diet was euphausiids, Calanus spp., and Sagitta spp. (Dudnik and Usoltsev 1964). Nearly 75 percent of herring stomachs examined in the spring from Bristol Bay to Norton Sound either were empty or contained only traces of food (Barton 1978). Only 25 percent of the stomachs examined were at least 25 percent or more full, and only percent were completely full. Major food items were cladocerans, flatworms (Platyhelminthes), copepods, and cirripeds. DISTRIBUTION Stock distribution Three major herring wintering grounds have been identified within the Bering Sea: northwest of the Pribilof Islands, in the Gulf of Olyutorski (Prokhorov 1968), and near Cape Navarin (N. Fadeev, TINRO, Vladivostok, , personal communication) (Fig. 32-7). Differences in the pattern of migration be- tween the coast and the outer continental shelf have effectively isolated Asian and North American herring in the Bering Sea. The different grovi^h and matura- tion rates and dissimilar age structures reported by Kachina (1978) of those win
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