Author: Julie Bednarski

Publisher:

Published: 2022

Total Pages: 0

ISBN-13:

Estimates of the inriver abundance of Taku River sockeye salmon, Oncorhynchus nerka, are needed to assess the achievement of the spawning escapement goal and international harvest sharing arrangements for stocks specified by the U.S./Canada Pacific Salmon Treaty (Treaty). The Taku River capture-recapture project has been conducted annually since 1984 as a joint U.S./Canada program involving the Alaska Department of Fish and Game (ADF&G), Fisheries and Oceans Canada (DFO), and the Taku River Tlingit First Nation (TRTFN). The objectives of the studies are to provide estimates of the inriver abundance of Taku River sockeye salmon and to document biological characteristics (migratory timing, migratory rates, final fates, and age, sex, and size composition) of stocks. Sockeye salmon are captured via fish wheels at Canyon Island on the U.S. side of the border and the recapture consists of sampling (inspecting) sockeye salmon for tags above border in the Canadian commercial and assessment fisheries. Tagged-to-untagged ratios of salmon harvested in the Canadian inriver gillnet fisheries are used to develop the estimates of the inriver abundance of sockeye salmon. Additionally, ADF&G, in cooperation with DFO and TRTFN, will continue a sockeye salmon radiotelemetry study on the Taku River to clarify recent insights into key assumptions of annual Taku River sockeye salmon capture–recapture studies that have potential to influence abundance estimates. An array of fixed towers throughout the drainage and fixed-wing aerial surveys will be used to track radiotagged sockeye salmon to determine final fates in the drainage, to determine annual fish dropout rates (defined as any fish tagged during event one at the Canyon Island fish wheels that did not cross the border and therefore was not available for recapture in event two of the capture–recapture project), and to estimate the proportion of mainstem and lake spawners.