Spring Chinook Salmon Fishing Update 5/14/2024: Rapid River Run, Hells Canyon, and Clearwater River Fisheries

Hi everybody.

It is time for my weekly spring Chinook Salmon update (May 14, 2024). So, let’s get right to it.

RUN UPDATE

During my last update on May 8, I mentioned that we needed Chinook Salmon counts at Bonneville to pick back up or at least stabilize for a few more days for us to achieve or exceed our preseason forecast. Well, it just happens that counts picked up last week almost duplicating what occurred the previous week (see red line in Figure below). This is great news especially since many were unsure if we would get another surge like this.

If you look at the red line in the figure below, you will see that about 72,000 adult Chinook Salmon passed over Bonneville Dam between March 15 and May 13 this year. This is the second best count we have seen for this time period since 2016 – only during 2022 were more fish counted. I suspect that when Idaho’s spring Chinook Salmon run ends at Bonneville Dam (typically around May 30), it will end up being similar to what we saw last year (dotted black line). This is actually close to what we forecasted before the season started.

Now, let’s take a look at PIT tag detections at Bonneville Dam so we can evaluate how many of these fish are headed to Idaho. To do this, I created the figure below that summarizes the daily PIT tag estimates of fish destined for the Clearwater and Rapid River run fisheries. There are several things I want to point out in this figure. First, the daily counts bounce around more from day to day (in comparison to total Bonneville daily counts) because each detected PIT tag can represent anywhere from 36 to 112 fish depending on which release group it came from. Second, you should notice that more fish are destined for the Clearwater (70%) than the Rapid River hatchery (30%). It is perplexing to see the Clearwater River return coming in higher than we forecasted whereas the Rapid River return is coming lower than forecasted. Finally, pay attention to when these counts spiked (around May 3-5). Right now, these fish are taking about two weeks to migrate from Bonneville Dam to Idaho. So, get ready if you like to fish the lower Clearwater.

All right, let’s look at what these PIT tag detections tell us about our harvest shares. I have updated the table below, so it now captures the most recent data (through 5/13/24). This table shows that the Clearwater River fishery's harvest share is projected to be 4,567 adult fish (darker peach row) which is up from last week’s estimate (3,789 fish). The Rapid River return fishery (darker blue row) is projected to have a harvest share of 2,060 which is up from last week’s estimate (1,854 fish). Finally, Hells Canyon’s fishery (green row) is projected to have a harvest share of 734 fish which is also up from last week (684 fish). These projections are based on the assumption that these returns have an average run timing - about 85% complete at Bonneville Dam.  

Because the Clearwater River return is coming in significantly higher than forecasted, IDFG staff will be recommending to the commission this week (May 16) to follow the guidelines displayed in the “harvest matrix” anglers helped developed and support (see Chinook update 4/25/2024 for details). Specifically, the recommendation will be to increase the number of days one can fish from 4 days/week to 7 days/week. This would not apply to the North Fork which would remain at 4 days/week. Additionally, IDFG staff will recommend to increase the daily limit in the South Fork Clearwater River from a 1 adult to a 2 adults. We will keep you posted on the commission’s decision.

FISHERIES

Clearwater River Basin Fishery

I was expecting much better fishing on the Clearwater River than we observed last week. Based on our creel surveys, we estimated seven adults and four jacks were harvested, all from the lower Clearwater, with catch rates exceeding 100 hrs/fish. A couple anglers also reported catching and releasing a fish in the North Fork. That brings the season harvest total to 9 adult fish. During the upcoming weeks, I will include a table that shows how many fish anglers are catching and where they are being caught. This table will be useful in evaluating where the best fishing is and how long specific river reaches will remain open before harvest distribution goals are met. 

Flows are supposed to rise above 40,000 cfs this weekend in the Clearwater River. This amount of flow often provides good fishing as it is high enough to push the fish towards the bank but slow enough to not impede migration. However, I will caution that because this will be the highest flows that have occurred this spring, floating debris and dirty water could become an issue. If debris and dirty water is not an issue, fishing could be good as over 350 Clearwater River bound fish have passed over Lower Granite Dam each of the past two days (based on PIT tags), and it should only continue to increase over the week next week. 

Rapid River Run Fishery

We did not observe any fish being harvested in the lower Salmon River or Little Salmon River last week.  However, four fish were trapped at Rapid River fishery hatchery last week, and Rapid River hatchery PIT tagged fish have been passing over Lower Granite Dam for the past 10 days. Some of these fish should be entering the lower end of the fishery by now.  This means, if you want to give it a try next week, there is a chance you will catch one. Flows in the Salmon River are forecasted to reach 50,000 cfs this weekend. These flows can cause delays in fish migration at the Slide Rapid; however, it appears they will only remain at this level for day or two before dropping back down.

Hells Canyon Fishery

Hells Canyon was the hot spot last week. We estimated that 24 Chinook were harvested last week, all just downstream of Hells Canyon Dam. Catch rates were decent at 14 hrs/fish. Trapping at the dam will likely not occur for a couple more weeks which will allow these fish to stack up and improve catch rates. 

Have fun and be safe.