Genetic Stock Identification of Chinook Salmon Mixtures at Bonneville Dam. Final Report to the Pacific Salmon Commission.
The objective of this project was to identify stock composition and run timing of summer and fall Chinook salmon passing Bonneville Dam. Included in this study was an evaluation of the cut-off date that designates the start of the summer run of Chinook salmon. A total of 1163 samples collected at Bonneville Dam from June 1 to October 20, 2005 were genotyped with 13 microsatellite loci. A genetic baseline of 55 populations was utilized to complete genetic stock identification of unknown origin samples from Bonneville Dam. Of the 450 samples collected as summer run Chinook (June 16 to July 19), the majority (90.2%) were from the mid/upper Columbia River reporting unit (Hanford Reach/Methow River) with very minor contribution from Snake River (1.6%) and Klickitat River (1.4%) reporting units. Of the 515 fall run samples collected from September 9 to October 20, a much larger proportion of the mixture was composed of Snake River (21.7%), Klickitat River (3.7%), and Deschutes River (3.0%) reporting units relative to the summer collection. However, the fall mixture was still dominated in composition by the mid/upper Columbia River reporting unit (70.1%). This study demonstrated the utility of GSI methods for evaluating stock composition of Chinook salmon mixtures from Bonneville Dam and potential for managing fisheries with this additional information.
Narum, S.R., D. Hatch, and J. Whiteaker. 2007. Genetic stock identification of Chinook salmon mixtures at Bonneville Dam. Final Report to the Pacific Salmon Commission. Columbia River Inter-Tribal Fish Commission, Portland.