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Genetic (DNA) Stock Composition Estimates for Nass River Sockeye Salmon Returns to the Gitwinksihlkw Fishwheels, 2000–2021, and Preliminary Run Reconstructions of Nass River Sockeye Stocks, 1982–2021

author Alexander, R.F., et al.
published year 2023
document type technical report
species sockeye
location Nisga'a Territory, British Columbia
subjects stock estimate, fishwheel, run reconstruction, DNA
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Genetic (DNA) stock composition estimates were derived from adult Sockeye Salmon (≥ 450 mm nose fork length) sampled at two fishwheels operated in the lower Nass River (Gitwinksihlkw, BC) between 2000 and 2021 for 14 years that were funded for analyses. The Pacific Salmon Commission’s Northern Fund (Vancouver, BC) funded six years of the genetic analyses that totaled 3,366 samples. Other analyzed years were funded by Nisga’a Lisims Government (NLG), Fisheries and Oceans Canada (DFO), and Coast Funds (Vancouver, BC) in 2018 for genetic analyses of 271 radio-tagged Nass Sockeye Salmon.

The primary objectives of the genetic analyses of the Nass River fishwheel Sockeye Salmon samples were to: 1) determine stock proportions of all Nass Sockeye stocks in analyzed years, 2) compare stock proportions to aggregate population and net escapement estimates for Nass Sockeye returns for analyzed years, 3) evaluate the effectiveness of commercial salmon fishing closures in Area 3 from 2011 to 2021 in rebuilding/recovering the Kwinageese River Sockeye Salmon stock that was impacted by an in-river migration barrier (slide) detected and
remediated in 2011, 4) utilize the genetic stock composition estimates for updating the northern boundary Sockeye run reconstruction (NBSRR) model for estimating Nass Sockeye Salmon sub stocks, and 5) review genetic data with DFO and Alaskan Department of Fish and Game (ADFG) to assess baseline stocks that are used for determining the number of Nass Sockeye Salmon caught in commercial marine fisheries in Alaska and BC as part of annual harvest determination in Pacific Salmon Treaty’s Sockeye Salmon fisheries.