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Migratory Timing of Upper Copper River Sockeye Salmon Stocks and Its Implications for the Regulation of the Commercial Fishery
Author(s) -
Merritt M. F.,
Roberson K.
Publication year - 1986
Publication title -
north american journal of fisheries management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.587
H-Index - 72
eISSN - 1548-8675
pISSN - 0275-5947
DOI - 10.1577/1548-8659(1986)6<216:mtoucr>2.0.co;2
Subject(s) - stock (firearms) , fishery , oncorhynchus , canyon , geography , environmental science , fish stock , fishing , biology , fish <actinopterygii> , cartography , archaeology
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 stocks. The majority of migratory time densities were positively skewed, platykurtic forms which were relatively stable between years. Migratory timing of upper river stocks overlapped and harvest control of individual stocks within the Copper River District of Prince William Sound may not be feasible. However, management of groups of stocks according to clusters of time‐density means is feasible. Identification of the upper Copper River stock composition within a commercial fishery period can assist the manager in assessing stock abundance and the probable impact of the fishery on groups of stocks.