Migration of Salmon In Hood Canal

Migration is a fundamental component of the life history and ecology of many species, but the extent and duration of specific migrations can vary depending on species and environment. Chinook salmon, Oncorhynchus tshawytscha, are characterized by a spectrum of life history types having different migrations and distributions. The objective of this study was to quantify the movements of yearling Chinook salmon smolts during their initial summer in Hood Canal, a long, narrow fjord in western Puget Sound, Washington. Fifty eight yearling hatchery-reared smolts were tagged with acoustic transmitters and tracked from May through August 2008 using a network of 50 receivers placed throughout Hood Canal. A total of 41 fish were detected during the study period, and 18 were still detected in Hood Canal after 100 d. Fish initially congregated near the release site and gradually dispersed during summer, with individual movement rates ranging between 0.44 and 1.52 body lengths/s. Fish movement occurred both with and against tidal currents, and nearly all fish showed some period of inactivity, especially as recorded on receivers near estuaries and tidal deltas. Very few fish were detected leaving Hood Canal during the study, and all but one that left returned to Hood Canal. The extended use of Hood Canal as rearing habitat during the initial migratory period indicated the importance of such environments beyond their role as migratory corridors.