Idaho's Steelhead Fishery Update, September 2, 2025

Hi everybody. With Idaho's fall steelhead season starting to kick into full gear, I figured now would be a good time to put out a fall steelhead update. In this update I will be discussing Idaho's early and late steelhead returns and what you could expect in the future.

STEELHEAD

Idaho's Early Summer Steelhead Run (destined for the upper Salmon, Little Salmon and Snake rivers)

Right now, most Idaho bound steelhead that have passed over Bonneville Dam are early run summer steelhead that are destined for the upper Salmon, Little Salmon, and Snake rivers. These fish pass over Bonneville Dam on average about a month earlier than fish destined for the Clearwater River basin. Evidence suggests that about 72% of this run has passed over Bonneville Dam (as of September 1, 2025) which gives us a good understanding of what you can expect this year for this fishery. As an FYI, the "Dworshak stock" steelhead that are released in various places in the Salmon River drainage are not included in assessment as they represent a small portion of this return and have a later run timing similar to the fish returning to the Clearwater River.

To help portray how this year's early return compares to previous years, I have put together the figure below. This figure was developed using PIT tag detections collected at Bonneville Dam since 2014. In this figure, the solid red line shows the number of fish that have passed over Bonneville Dam to date (through September 1), and the dotted red line shows the number of fish we project will cross the dam (assuming 72% of the run is complete). This data shows that about 18,000 early hatchery steelhead destined for the upper Salmon, Little Salmon, and Snake rivers have passed over Bonneville Dam as of 9/1/2025 with the run projected to reach around 26,000 fish. One thing I need to point out is this data does not include returns of 1-ocean steelhead raised at Magic Valley hatchery that were released in the upper Salmon and Little Salmon rivers last year. Steelhead were not PIT tagged at this hatchery last year (2024) due to disease concerns which prevents us from tracking their return. If these fish survive at similar rates as has occurred in the past, we project that about 3,500 more 1-ocean steelhead will pass over Bonneville Dam than the figure below projects. This would bring the final run projection over Bonneville Dam close to about 30,000 fish which is similar to what occurred in 2016 (yellow line).