Contacts: John Hilsinger at (907) 267-2324 or Charlie Swanton at (907) 465-6184
The Alaska Department of Fish and Game (ADF&G) today released revised escapement goals for Susitna River sockeye salmon and an accompanying Fisheries Technical Manuscript report. Based on extensive research by the department, it became evident that a revision was needed for the existing escapement goal for Yentna River sockeye salmon because the Bendix sonar was substantially undercounting sockeye salmon.
For several years, ADF&G has been operating two types of sonar as well as doing weir counts and mark-recapture experiments to enumerate sockeye salmon returns. Data analysis showed that the older model Bendix sonar was significantly undercounting fish relative to the newer Dual-frequency Identification Sonar (DIDSON) style counter, weirs at major spawning lakes, and the mark-recapture population estimates. Since the escapement goal for the Yentna was based on these Bendix sonar counts, an ADF&G interdivisional team of biologists completed an exhaustive analysis of historical data including weir, sonar, and mark-recapture programs conducted over 25-30 years incorporating various sockeye salmon production models to develop an updated escapement goal. The results of these analyses affirm that replacing the existing Yentna River sustainable escapement goal of 90,000-160,000 sockeye salmon with weir count based escapement goals will provide a more accurate and reliable management target that incorporates escapement into the mainstem Susitna River as well as the Yentna River. For the Yentna River drainage, weir count based escapement goals of 20,000-65,000 fish for Chelatna Lake and 25,000 to 55,000 spawners for Judd Lake will be used. An escapement goal of 15,000-50,000 fish for Larson Lake will be used as a proxy for the Susitna River mainstem.
These goals will be reviewed every three years coinciding with the Alaska Board of Fisheries management cycle. The DIDSON sonar counter (located on the Yentna River six miles upstream from the confluence with the Susitna River) will continue operation, providing indices of sockeye salmon passage throughout the run.
Inseason salmon fisheries management actions will rely on data from the offshore test fishery and catch per unit of effort indices from the drift gillnet and set gillnet fisheries under guidance of the Yentna River sockeye salmon stock of concern action plan. Research activities will be conducted over the next 4-5 years to allow for increased understanding of sockeye salmon production, species apportionment, and total abundance.
