Migratory Timing of Upper Copper River Sockeye Salmon Stocks and Its Implications for the Regulation of the Commercial Fishery

Abstract

Abstract Migratory timing of 15 sockeye salmon (Oncorhynchus nerka) stocks in the upper Copper River, Alaska, was determined from a tag and recapture project conducted between 1967 and 1972. Time densities and descriptive statistics were used to estimate mean date of migration upstream, variation about the mean, form, and stability of these measures between years within the geographic reference frame of Wood Canyon. The mean calendar dates of migration through the Copper River commercial fishery district of Prince William Sound also were estimated. River level appeared to have a negative correlation with travel rate and was a source of yearly variation in the mean date of migration. Mean dates of migration varied by stock and were grouped by a Student-Newman-Keuls test into six time spans that significantly differed from one another. Variation in mean migration date increased through time, with earlier migrating stocks demonstrating greater consistency of timing between years than the later migrating stoc...