Northwest Fisheries Science Center

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Document Type: Journal Article
Center: NWFSC
Document ID: 7882
Title: Migration and survival of Redfish Lake, Idaho, sockeye salmon, Oncorhynchus nerka
Author: Ted C. Bjornn, Donovan R. Craddock, D. R. Corley
Publication Year: 1968
Journal: Transactions of the American Fisheries Society
Volume: 97
Issue: 4
Pages: 360-373

Most adult sockeye salmon returning to Redfish Lake had spent 2 years in the ocean.  Survival from smolt to returning adult at the lake ranged 0.14–1.83%.  The sex ratio was nearly even.

Survival of sockeye in the lake from potential egg deposition to smolt migration was usually less than 6%.  In at least one year, smolts originating from kokanee and/or residual sockeye may have comprised a large proportion of the migration.  There was little relationship between egg deposition and smolts produced. 

Sockeye salmon smolts migrated from Redfish Lake primarily from 1800 to 2400.  There was no consistent relationship between seasonal timing of the migration, lake ice cover, temperatures, or flow of the outlet stream.  The role of photoperiod in timing of the migration and the parr–smolt transformation is unclear. 

Growth of juvenile sockeye in the lake was inversely related to population density, and age at migration was dependent upon first–year growth in the lake.  More than one–half the fish of a year class migrated as yearlings when their mean length was more than 85 mm.  When the mean length of yearlings was less than 85 mm, less than one–half the fish of a year class migrated as yearlings.

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