MIGRATION OF ALBACORE, THUNNUS-ALALUNGA, IN THE NORTH PACIFIC-OCEAN IN RELATION TO LARGE OCEANIC PHENOMENA

On the basis of Japanese long-line fishery data during 1970-1988, anti clockwise migration routes of albacore in the North Pacific an newly p roposed. The annual migration route for mature albacore is described a s a closed ellipse with a centre at 20 degrees N and 170 degrees E, an d is wider in El Nino years than non-El Nino years associated with an appearance of a cold-water region in the central and south-western Nor th Pacific. Immature albacore also have an anticlockwise migration rou te in winter which extends from 25 degrees N to 35 degrees N and from 130 degrees E to 180 degrees E, when the Kuroshio has a relatively str aight path. However, the migration does not persist when the Kuroshio takes a large meander path.