Tag Archives: transboundary rivers

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

 

Mixed stock analysis of districts 108 and 111 chinook fisheries

The Stikine and Taku rivers in Southeast Alaska (SEAK) support Chinook salmon runs important for various commercial, aboriginal, and recreational fisheries in both the United States (U.S.) and Canada. Included in these are U.S. commercial gillnet fisheries in Alaskan Districts 108 and 111, as well as sport fisheries near Wrangell, Petersburg, and Juneau. U.S. fisheries in these areas harvest stocks of Chinook salmon bound for SEAK and for tributaries in the transboundary Stikine and Taku rivers. Catches of Stikine and Taku river Chinook salmon stocks are subject to a harvest sharing agreement, in which the U.S. and Canada are each given an Allowable Catch specified by the Pacific Salmon Commission, and this relies on catch, escapement, recruitment information, and stock composition estimates to forecast indices of abundance. Until recently, stock composition of harvests was estimated primarily using coded-wire tags, which provided good estimates for marked stocks. However, expansions of these estimates could be uncertain due to a lack of coded-wire tags on all stocks contributing to the fishery, incomplete tagging of index stocks, and in some instances poor estimates of escapement or terminal run size. Genetic stock identification (GSI) provides a complementary set of accurate and reliable stock composition estimates necessary to meet the directives of abundance-based management of Chinook salmon, and is currently used to recalculate actual contributions of above-border Stikine and Taku Chinook salmon to the Districts 108 and 111 sport and commercial fisheries.

N18-VHP01 Mixed stock analysis of districts 108 and 111 chinook fisheries Report 2018

N17-VHP06 Mixed stock analysis of districts 108 and 111 chinook fisheries Report 2017

N16-I59 Mixed stock analysis of districts 108 and 111 chinook fisheries Report 2016