Tag Archives: genetic stock analysis

Northern and Transboundary Sockeye Matched Scale-Tissue Sampling

Provisions of the 1999 Pacific Salmon Treaty (PST) specify abundance-based harvest sharing arrangements of Nass and Skeena River sockeye salmon returns for the U.S. and Canada. The United States is allowed to harvest a fixed percentage of the annual allowable harvest of Nass and Skeena sockeye stocks in Alaska’s District 101 gillnet and District 104 purse seine fisheries. Accurate estimates of the stock-specific catch in commercial fisheries of each nation are required to estimate the total return of these stocks and the percentage of each stock caught in treaty-limited fisheries.
Since 1982, scale pattern analysis (SPA), sometimes in conjunction with other biological markers, has been used to survey the weekly catch of Northern Boundary and Transboundary sockeye salmon stocks in Southeast Alaska fisheries. However, problems in accurately estimating stock-specific catches and total returns of sockeye salmon in the early years of the Pacific Salmon Treaty resulted in an extensive investigation, and it was concluded that improved stock identification techniques, such as genetic stock analysis, were needed to accurately evaluate effectiveness and improve, if possible, existing run reconstruction methods. Two blind tests of scale analysis vs. genetic analysis demonstrated that, while both techniques were accurate, the genetic analysis had higher precision and could also often identify many specific stocks, while scale analysis is limited to identifying a few stock-groups. Neither technique can identify enhanced fish where the brood stock came from wild stocks that are also present in the mixed stock fisheries; thus, otoliths are used in annual stock composition estimates and run reconstructions.
ADF&G proposes to continue collecting weekly otolith, tissue, and scale samples of sockeye from the Southeast Alaska commercial harvest in the District 101 gillnet and District 104 purse seine fisheries, among other districts and fisheries for projects that complement this program. Stock identification analysis using age composition, thermal mark presence, and new, more stock-discrete DNA techniques will be conducted at NOAA’s Auke Bay Laboratory. This project also complements the continuing work by DFO in Areas 3, 4 and 5.

N18-I06 Northern & Transboundary Sockeye Salmon Matched Scale-Tissue Sampling Report

N17-I07 Northern & Transboundary Sockeye Salmon Matched Scale-Tissue Sampling Report

N16-I05 Northern & Transboundary Sockeye Matched Scale-Tissue Sampling. Year 9

N15-I08 Northern and Transboundary Sockeye Matched Scale-Tissue Sampling. Year 8

N14-I07 Northern and Transboundary Sockeye Matched Scale-Tissue Sampling. Year 7

N13-I07 Northern and Transboundary Sockeye Matched Scale-Tissue Sampling. Year 6

N12-I05 Northern and Transboundary Sockeye Matched Scale-Tissue Sampling. Year 5

N11-I13 Northern and Transboundary Sockeye Matched Scale-Tissue Sampling. Year 4

N10-I10 Northern and Transboundary Sockeye Matched Scale-Tissue Sampling. Year 3

N08-I12 Northern and Transboundary Sockeye Matched Scale-Tissue Sampling. Year 2

N07-I25 Northern and Transboundary Sockeye Salmon Matched Scale-Tissue Sampling

 

Genetic Stock Identification 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.

N17-I06 Mixed stock analysis of U.S. Districts 106, 108, and 111 sockeye salmon gillnet fisheries Report

N16-I06 Genetic Stock Identification of Districts 106, 108 and 111 Sockeye Report 2016