A Genetic Analysis of the Summer Steelhead Stock Composition in the Columbia River and Snake River Tribal and Sport Fisheries from July 1, 2012 to March 31, 2013
We used PBT and GSI to categorize the stock composition of steelhead harvested in tribal and non-tribal fisheries in the Columbia and Snake rivers. This is the second year that we have used genetic technology to parse harvest into stocks. All steelhead used for broodstock in the Snake River basin have been genotyped since BY09, allowing us to identify Snake River hatchery origin fish with PBT. Samples from unclipped adipose fin steelhead that did not assign to a Snake River hatchery stock with PBT were assigned to a reporting group using GSI. We sampled the lower Columbia River sport fishery from July 1 to October 31, 2012 and the Zone 6 tribal fishery from August 1 to November 10, 2012. In 2012, we expanded the area sampled compared to 2011 by sampling sport fisheries in Zone 6 and in the Snake River from its mouth upstream to Lower Granite Dam. The Snake River downstream of Lower Granite Dam was sampled from September 1, 2012 to March 31, 2013. We found that the majority of steelhead sampled came from the Snake River basin in all fisheries. Snake River basin hatchery stocks made up 70% of the lower Columbia sport catch, 85% of the clipped harvest in the tribal Zone 6 fishery, 25% of the unclipped tribal Zone 6 catch, and over 99% of the Snake River catch. Although harvest estimates were unavailable for the sport fisheries we sampled in Zone 6, we estimated that the Snake River basin stock composition was 73% in Washington shore area, 95% in the mouth of the Deschutes River area, and 100% in the John Day Arm.
Byrne, A., J. Hymer, S. Ellis, R. Dick II, K. Keller, C.A. Steele, J.E. Hess, M. Begay, and J.D. Bumgarner. 2014. A genetic analysis of the summer steelhead stock composition in the Columbia River and Snake River Tribal and Sport fisheries from July 1, 2012 to March 31, 2013. Idaho Department of Fish and Game Report No. 14-12. Boise, ID. 77p.