Density-Dependent Growth of Sockeye Salmon in the North Pacific Ocean

摘要

Length measurements were obtained for sockeye salmon from several major rivers around the perimeter of the North Pacific Ocean. The salmon from the Kvichak River in Bristol Bay, Alaska exhibit strong cyclic changes in abundance, usually with a period of 5 years. The lengths of salmon show the same cyclic changes but are inversely related to the magnitude of salmon abundance. The same relationship was found for all streams in Bristol Bay. The strength of this association was measured by the correlation coefficients between the same age-classes in other districts. High values were interpreted as occupation of overlapping feeding areas by each age-class during the last year in the ocean before salmon reach full maturity. There was some overlap in feeding areas of salmon from neighboring districts such as the Copper River and the Karluk/Chignik watersheds in Alaska. No association was found between Bristol Bay sockeye salmon and their counterparts in either Russia or the Fraser River, British Columbia, Canada.