Lewiston, ID

IDFG: Spring Chinook Salmon Run is Unprecedentedly Late This Year

Mia Carlson

Idaho Spring Chinook Salmon are on the way, but it is one of the latest runs in history.Photo byIDFG - Clearwater Region

LEWISTON, ID - The Idaho Department of Fish and Game has released its Spring Chinook Salmon update. Clearwater Region Fisheries Manager Joe DuPont says it is hard to project just how many fish are yet to come "when it appears we are dealing with one of the latest spring Chinook returns in history."

Last week fisheries officials did not observe any fish being harvested.

"However, I have heard of a couple [of] reports of fish being caught this week around Lewiston. We won’t summarize the harvest data for this week until next Tuesday, so stay tuned for that. Right now, catch rates are really slow, and I don’t expect them to get decent until this surge of fish passing over Bonneville Dam gets to Idaho. They should arrive here in 10-14 days," according to DuPont.

In his last update on May 2nd, DuPont said counts were picking up which gave them hope.

"However, from May 2 to May 7, counts dropped and then leveled out. At this point we weren’t even sure if enough fish would make it to Idaho to provide fisheries. Since then, counts have spiked and now we are confident we can provide fisheries; we just aren’t sure what type of fisheries we can provide," DuPont says.

DuPont says it is hard to project just how many fish are yet to come when it appears they are dealing with one of the latest spring Chinook returns in history.

"The only year I found that had a later run timing was 2017," DuPont adds. "In 2017 we experienced some really high flows in the Columbia River which we think caused that return to be so late. Flows are quite a bit lower this year in comparison to 2017, so I’m not real confident that we expect another late peak like we did in that year. However, this run appears unprecedented so strange things could happen."

Adult Spring Chinook Salmon Counts at Bonneville DamPhoto byIDFG - Clearwater Region

DuPont says they looked at PIT tag detections at Bonneville Dam on the Lower Columbia River so they can evaluate how many of these fish are headed to Idaho.

"I decided to create a new figure for you that summarizes PIT tag detections of fish destined for the Clearwater and Rapid River run fisheries to give you a feel for how these counts compare to the overall Bonneville Dam counts (see figure below)," DuPont says.

Idaho Spring Chinook Salmon Daily Counts at Bonneville Dam Based on PIT TagsPhoto byIDFG - Clearwater Region

"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 22 to 136 fish depending on which release group it came from. Second, you should notice that more fish are destined for the Clearwater (60%) than the Rapid River hatchery (40%). Finally, I want to point out the if you combine the counts of the of these two fisheries, the highest count occurred yesterday (5/11/23). Hopefully, this means passage of Idaho’s spring Chinook Salmon over Bonneville Dam has not peaked and will continue to climb," according to DuPont.

What do these PIT tag detections tell DuPont about Idaho's harvest shares?

"I have updated the Table below, so it now captures the most recent data (through 5/11/23). This table shows that the Clearwater River return’s harvest share is projected to be 1,922 adult fish (darker peach row) which is up from last week’s estimate (1,705 fish). The Rapid River return (darker blue row) is projected to have a harvest share of 1,382 which is down from last week’s estimate (2,240 fish). Finally, Hells Canyon’s (green row) projected harvest share is 260 fish which is also down from last week (362 fish). It is important to realize these harvest shares assumed that the run has an average, late timing (about 65% complete). However, if the return is even later than that (similar to 2017), the harvest share will go up," DuPont says.

PIT Tag EstimatesPhoto byIDFG - Clearwater Region

DuPont says the harvest matrix for both the Rapid River return and Clearwater fisheries indicate that if the harvest share is below 2,000 adult fish, the season would drop down to four days a week (Thursday – Sunday) with a one-adult daily limit, but anglers should not be surprised if changes in the seasons and limits occur next week.

He points out that Sawthooth Hatchery fish have been passing over Bonneville Dam for the past week which means that these fish will be mixed in with the Rapid River fish as they ascend the lower Salmon River.

"The significance of this is that we want to minimize harvest of the Sawtooth fish in the lower Salmon so that we can provide a fishery on them in the upper Salmon River basin. Where we have the most impact on these upriver fish is in the lower Salmon River downstream of Hammer Creek. As such, I want to give you all a warning that it may be necessary to shut this section of river down fairly quickly. The section of river between Hammer Creek and Time Zone Bridge may also face a similar challenge. We will keep you appraised of this issue as the season progresses," DuPont says.

More details about the Chinook runs can be found HERE.

Fish counts for Columbia and Snake River dams can be found HERE.

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I am old-school journalism - who, what, where, when, why, and how; and "leave your opinion out of it." Decades of experience covering the region of north-central Idaho and southeast Washington State.

Lewiston, ID

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