Tag Archives: scale pattern analysis

Mixed Stock Analysis of Districts 106, 108 and 111 Sockeye

Sockeye runs from the Stikine and Taku rivers in Southeast Alaska are harvested in Canadian aboriginal, recreational, and commercial gillnet fisheries, and in US subsistence, personal use, and commercial gillnet fisheries. In the US, commercial gillnet fisheries in Districts 106 and 108 harvest wild stocks of sockeye salmon bound for Southeast Alaska island and mainland lakes, and for lakes and tributaries in the Stikine, Nass, and Skeena River drainages, while fisheries in District 111 harvest wild stocks of sockeye primarily bound for systems in the Taku River or to Crescent and Speel lakes in Alaska. Significant numbers of enhanced sockeye salmon bound for release sites in the Stikine and Taku rivers or to Snettisham Hatchery are also caught in these fisheries. Catches of Stikine and Taku river sockeye salmon stocks in Districts 106, 108 and 111 gillnet fisheries and the U.S. Stikine subsistence fishery are subject to a harvest sharing agreement outlined in Annex IV of the Pacific Salmon Treaty, in which the US is allowed 50% of the Total Allowable Catch of Stikine River and a variable proportion of Taku River sockeye salmon depending on the return of enhanced fish. Stock contribution estimates are critical to document compliance with the harvest sharing agreements, reconstruct runs of wild stocks, estimate the return of enhanced fish, forecast upcoming returns, and support sustainable management.
Genetic stock identification (GSI) is the preferred method for estimating stock contributions in fisheries in and near the Stikine and Taku rivers, and has been in use for transboundary management since 2011. GSI has improved estimates compared to past methods (scale pattern analysis), and is less logistically complex, less labor intensive, less expensive, more accurate, and delivers more timely results at a finer resolution.
This project has been conducting GSI analysis on sockeye salmon tissue samples collected from commercial gillnet fisheries in areas in and near the Stikine and Taku rivers in Southeast Alaska since 2012. The analysis will be focused on tissue samples collected in Districts 106, 108, and 111.