Upper Cook Inlet salmon return timing

A critical aspect in attaining adequate salmon spawning escapement levels for Northern Cook Inlet (including the Mat-Su Valley) is the difference in salmon return timing between Central District stocks (Including Kasilof and Kenai River sockeye ) and Northern District stocks ( including Larson Creek sockeye, Chelatna Lake sockeye, Little Susitna River coho and Deshka River coho salmon).

Kasilof Sockeye

The earliest drift gillnetting in Upper Cook Inlet starts around July 20 as the Kesilof River sockeye salmon returns is building. Sonar counts of Kasilof River sockeye traditionally start on June 15, and on that date this year the Alaska Department of Fish and Game (ADF&G) estimated over 11,000 sockeye passing the Kasilof River sonar counter located near the Sterling Highway — just a few miles above tidewater. On June 30, more than 25% of ADF&G’s 2025 Kasilof River sockeye estimate had already swum past the sonar with a cumulative count on that date of 255,868 sockeye. Even with this early abundance of Kasilof sockeye salmon, however, drift gillnetting time is usually limited to better ensure adequate July escapements of Kenai River sockeye.

The 2025 Kenai River Late-run Sockeye salmon sonar counts started on July 1 with ADF&G estimating passage of 7,312 sockeye past two sonar counter (once again located just a few miles above tidewater). On July 20 more than 25% of ADF&G’s 2025 late-run Kenai River sockeye passage had swum past the department’s Kenai River sonar sites with a cumulative count on that date of 1,087,090 sockeye.

Fish Creek Sockeye In Northern Cook Inlet, Fish Creek provides the earliest sockeye return numbers with daily weir counts usually starting in early July at a weir site a few miles above tidewater. During 2026 the first Fish Creek sockeye (yes - one single fish) was counted on June 30. On July 18 more than 25% of ADF&G’s Fish Creek sockeye return had swum past Fish Creek Weir with a cumulative count on that date of 11,389 sockeye.

Larson Creek Sockeye Data entries on ADF&G’s website appear to indicate that 2025 weir counts at the Larson Lake site started on July 10, however, the first sockeye (yes - one sockeye) was not counted until 11 days later at this location — more than 100 miles upstream from the Susitna River terminus with Cook Inlet. On July 29 more than 25% of ADF&G’s 2025 sockeye total had swum past the weir with a cumulative total of 8,483 sockeye on that date.

Chelatna Lake Sockeye Weir operation appears to have started on July 18 at this location situated at the start of Lake Creek — more than 9 days travel time for sockeye by ADF&G estimate from Cook Inlet saltwater. The first two sockeye were counted on July 19. On July 27 more than 25% of ADF&G’s 2025 Chelatna Lake sockeye count had swum past the weir with a cumulative count of 17,886 sockeye on that date.

Deshka River Coho During 2025 Deshka River Weir was installed to start counting Chinook and other salmon on June 13, however the first 10 coho were counted passing the weir on July 26. The department counted some coho passing the weir every day for the next 33 days until the weir was flooded on August 29. On August 19 more than 25% of ADF&G’s 2025 Deshka coho total had swum past the weir with a cumulative total of 1,016 coho on August 19. Deshka Weir is located approximately 35 miles upstream from saltwater and in addition coho salmon migration is often sporadic and return timing can vary significantly between different seasons.

Little Susitna River Coho Little Susitna River Weir was relocated in 2025 to a site approximately 40 miles upstream from saltwater. Little Susitna River coho have been documented with migration timing that can be up to 3 weeks between tidal water and weir passage. In 2025 the weir was installed on July 23 with the first 10 coho counted passing the weir on July 29. On August 5 more than 25% of ADF&G’s 2025 Little Susitna River coho salmon passage occurred with a cumulative count of 1,197 coho through that date.

Management Implications for Varied Run Timings

In the Central District Kasilof Sockeye were atbove 25% of total sonar estimate on June 30. Kenai was above 25% on July 20. In the Northern District Fish Creek sockeye was above 25% on July 18, Larson Lake sockeye was above 25% on July 29, Chelatna Lake sockeye was above 25% on July 27, Little Susitna River coho was above 25% on August 6, and Deshia River coho did not top 25% until August 19. Since overall run timing is significantly later for the Northern Cook Inlet stocks the Department uses to judge commercial effort, and since both Keasilof and Kenai River sockeye stocks return in much higher numbers it is imperative that ADF&G manage the drift fishery, in particular, in a manner that historically has provided for adequate spawning escapement and season long harvest opportunities for Northern Cook Inlet user groups. After all, those two items — adequate salmon spawning escapements and harvestable surpluses for Northern Cook Inlet user groups — are the Board of Fisheries adopted purpose for the Central District Drift Gillnet Fishery Management Plan. Although the plan may allow ADF&G opportunity to fish the drift gillnet fleet in an excessively large portion of the Central District or may allow nearly unlimited weekly hours of drift gillnet fishing opportunity during specific portions of July and early August. ADF&G is clearly responsible for meeting the purpose of the plan. Since the past three years show a clear pattern of ADF&G allowing overfishing by the Central District drift gillnet fishery as measured by the purpose of the plan perhaps dirt gillnetting time and area within the plan should be more limited — in a precautionary manner — to what has historically allowed achievement of the plans purpose. See proposal 186: https://www.adfg.alaska.gov/static/regulations/regprocess/fisheriesboard/pdfs/2025-2026/proposals/186.pdf

Andy Couch is a member of the Matanuska - Susitna Borough Fish and Wildlife Commission and the Matanuska Valley Fish and Game Advisory Committee the thoughts and opinions expressed in this column are his own - unless noted otherwise.