Identification of Columbia Basin Sockeye Salmon Stocks Using Scale Pattern Analyses in 2001
In 2001, samples of adult Columbia Basin sockeye salmon (Oncorhynchus nerka) were collected at Bonneville Dam as well as at Tumwater Dam on the Wenatchee River and Wells Dam in the mid-Columbia River downstream of the Okanogan River. Tumwater and Wells dams were chosen to provide samples of sockeye salmon from the two principle stocks of Columbia Basin sockeye salmon, which originate from the Wenatchee and Okanogan basins. Additional samples were collected from the Zone 1-5 commercial fishery located in the Columbia River downstream of Bonneville Dam, the Zone 6 commercial fishery located between Bonneville and McNary dams, as well as the Wanapum tribal fishery just downstream of Priest Rapids Dam. Age composition was estimated from the sampled sockeye salmon passing the three dams, as well as for the sockeye salmon captured in the three fisheries. Four-year-old fish were estimated to comprise 81% of the mixed-stock sockeye salmon migrating past Bonneville Dam, 95% of the Okanogan stock migrating past Wells Dam, 54% of the Wenatchee stock migrating past Tumwater Dam, 88% of the Zone 1- 5 fishery, 78% of the Zone 6 fishery and 90% of the Wanapum fishery. Fiveyear- old fish were estimated to comprise 18% of the Bonneville Dam mixedstock, 2% of the Okanogan stock, 46% of the Wenatchee stock, 12% of the Zone 1-5 fishery mixed-stock, 17% of the Zone 6 fishery mixed-stock, and 10% of the Wanapum fishery mixed-stock. Three-year-old fish were estimated to comprise 1% of the Bonneville Dam mixed-stock, 3% of the Okanogan stock, none of the Wenatchee stock, none of the Zone 1-5 or Wanapum fisheries mixed-stock, and 3% of the Zone 6 fishery mixed-stock. Scale pattern analysis techniques were used to estimate that 68% of the Age 1.2 sockeye salmon, and 56% of the entire run, passing Bonneville Dam were of Okanogan stock, with the remaining percentage of Wenatchee stock. Sixty-six percent of the fish caught in the Zone 1-5 commercial fisheries 44% percent of the fish caught in the Zone 6 fishery, and 67% of the fish caught in the Wanapum tribal fishery were estimated to be of Okanogan stock, with the remainder of Wenatchee stock.
Fryer, J.K. and D.A. Kelsey. 2002. Identification of Columbia Basin Sockeye Salmon Stocks Using Scale Pattern Analyses in 2001. Columbia River Inter-Tribal Fish Commission Technical Report 02-02, Portland, Oregon. 42p.