Some Processes Affecting Mortality of Juvenile Fishes During the Spring Bloom in Prince William Sound, Alaska

Some Processes Affecting Mortality of Juvenile Fishes During the Spring Bloom in Prince William Sound, Alaska

T. Mark Willette, Ted Cooney, and Karen Hyer

Some Processes Affecting Mortality of Juvenile Fishes During the Spring Bloom in Prince William Sound, AlaskaThis is part of Ecosystem Approaches for Fisheries Management
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Description

Piscivory among herring (Clupea pallasi) and walleye pollock (Theragra chalcogramma) during the spring bloom in Prince William Sound, Alaska, was examined using field data. A midwater wing trawl equipped with a net sounder was used to sample adult pollock (>30 cm). Herring, immature pollock (<30 cm), and various juvenile fishes were sampled with smallmesh purse seines and variable-mesh gillnets. The diet composition of herring and pollock was estimated from specimens collected in 1994 (n = 4,106), 1995 (n = 7,342), and 1996 (n = 3,958). Herring, immature pollock, and adult pollock diets were generally dominated by large calanoid copepods (mostly Neocalanus) during the bloom of these copepods in May, but both fish species switched to alternative prey in June (Willette et al. 1999).

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