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FBE Focal Species - Walleye Pollock

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Walleye pollock, Theragra chalcogramma, is a member of the cod family and represents one of the most important fishery resources in the world with an annual catch rate of nearly 2 million metric tons in Alaska waters, and a value to the fishing community of 2 billion dollars per year. Walleye pollock are distributed from California through the Bering and Chukchi Seas to Japan, but the largest fisheries occur between the Gulf of Alaska and Bering Sea. The vast majority of pollock are captured with trawl gear and processed for frozen fish products and surimi.

arrow to eggs Pollock eggs (1.3 mm). arrow to larvae
Adult pollock (50 cm).

Pollock Life Cycle (click pix to enlarge)

Pollock larvae (6 mm).
arrow to adults Juvenile pollock (50 mm). arrow to juvenile

Walleye pollock are schooling, midwater to bottom-dwelling fish, living anywhere between shallow, nearshore waters to 1000 m. Most occur between 100-300 m depth. Generally, the fish move inshore during summer and offshore for winter, occupying greater depths during the cold months. Pollock may live up to 17 years and reach a length of 100 cm. Males and females are externally indistinguishable and typically begin to reproduce at 3-4 years of age. Spawning occurs at different seasons depending upon location; in Alaska between March and May. Females spawn in several batches over a few weeks, producing up to 2 million small eggs. The eggs hatch in 1-3 weeks at the depth of spawning (usually 100-250 m), and larvae develop in shallow water (<30 m). Young-of-the-year juveniles feed on plankton near the surface at night and descend during the day. Older fish consume copepods, shrimp, euphausiids, and fish. Walleye pollock are an important prey for a wide range of piscivorous fishes and marine mammals.

For details comparing pollock product value and catch percentages against other types of commercial groundfish in Alaska, see the AFSC pages on Walleye Pollock Research.

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Last updated 27 March, 2009

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