Tag Archives: genetic analysis

Northern Boundary Area Sockeye Salmon Genetic Stock Identification

Provisions of the Pacific Salmon Treaty specify 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. Annual catches over or under the agreed percentage are made up for in subsequent years.

Until recently, the Alaska Department of Fish and Game (ADF&G) used scale pattern analysis successfully to estimate contributions of Nass, Skeena and Southeast Alaska sockeye stocks to fisheries in southern Southeast Alaska. Since  2006, the Auke Bay Laboratories has used genetic analysis for the Northern Boundary sockeye fisheries. Results from comparisons between stock composition using scales and genetic analysis show both methods provide accurate estimates of stock composition, although DNA analysis is able to discriminate stocks at a finer resolution than scales. An additional advantage of the DNA technique is that it does not require annual sampling to re-establish the escapement baseline.

The purpose of this project is to continue the genetic stock identification of the commercial sockeye catch in ADF&G District 101 gillnet fishery and District 104 seine fishery using the baselines developed by the ADF&G.

Exploitation rate estimation for coho salmon in south coast marine fisheries using genetic stock identification

In 2014, an exploitation rate cap on Interior Fraser River (IFR) coho in Canadian fisheries was increased from 3% to 16% in response to improved status and rebuilding of these stocks as well as fishery needs. Pre-season predicted fishery impact on IFR coho was generally determined using historic (1986-97) exploitation and coded wire tag (CWT) recovery rates scaled by current effort, which have changed over time, so current CWT recoveries do not provide a measure of fishery impact. Instead, DNA will be used to estimate the number of ‘wild’ unmarked IFR coho caught in fisheries which would provide an independent estimate of exploitation rate.