Distribution of Juvenile Pacific Halibut (Hippoglossus stenolepis) in the North Pacific Ocean and Bering Sea

The distribution of adult Pacific halibut (Hippoglossus stenolepis) is well monitored off the coast of North America through various sampling programs. The distribution of younger halibut is less well-known, but can be estimated from the results of National Marine Fisheries Service surveys. Larval halibut are transported by major ocean currents to the north and west from the spawning grounds and, as one year olds are found primarily in the western Gulf of Alaska (GOA) and southeastern Bering Sea in Bristol Bay shallow nursery areas. By age two, halibut begin a counter-migration to the east and south in the GOA, and to the west and south toward the Aleutian Islands in the Bering Sea. Juvenile distribution expands as the fish age and halibut cohorts are widely distributed coastwide by about five years of age. Survival of young halibut depends on many factors including favorable currents for larval transport to inshore nursery areas, ocean temperature, intensity of predation, and availability of prey. Principal component analysis of selected environmental indices suggests a relationship in some years between environmental conditions and the relative success of halibut year classes.