Effects of natal origin on localized distributions of Chinook salmon, Oncorhynchus tshawytscha, in the marine waters of Puget Sound, Washington

The inland marine waters of Puget Sound, Washington, and the Strait of Georgia and associated waters of British Columbia (the Salish Sea) have long been recognized as alternative rearing habitat to the continental shelf for Chinook and coho salmon. Recent analyses have indicated that these fish (termed residents) comprise a substantial fraction of the Chinook salmon populations originating from Puget Sound rivers. However, the extent to which these resident salmon remain within their natal region or move within Puget Sound has not been studied. Analysis of two decades of coded-wire tagging data revealed several clear patterns. First, the salmon showed spatial distributions that varied systematically with area of origin. In general, they were caught in the vicinity of their origin, indicating limited net movement during several years at large; however this pattern was not universal. Second, recovery distributions were highly influenced by marine age and showed region specific spatial patterns, with the largest differences between the youngest (marine age 1) and oldest (marine age 4) individuals.