Spring Chinook Salmon Fishing Update 5/23/2023: Rapid River Run, Hells Canyon, and Clearwater River Fisheries

Hi everybody.

It is time for my weekly spring Chinook Salmon update (5/23/2023). So, let’s get right to it.

RUN UPDATE

Don't let yesterday's drop (from 2,500 to 1,500 fish) in daily fish counts make you think Idaho's spring Chinook run over Bonneville Dam is complete (see figure below). The high, dirty water appears to be influencing fish passage at Bonneville Dam which has many thinking some Idaho-bound spring Chinook are being held up there and more are yet to come.  We estimate that the migration of Idaho-bound spring Chinook Salmon past Bonneville Dam is around 90% complete. 

I have created a new figure (see below) to help you visualize how this year’s return (red line) of adult spring Chinook Salmon to Bonneville Dam compares to the previous 10 years. To date (March 15 to May 22), the total count for adult Chinook Salmon at Bonneville Dam is 97,758 fish. This would rank as the fifth best when compared to the previous 10 years.

The table below summarizes the most recent (through 5/22/23) PIT tag data collected at Bonneville Dam that we used to estimate harvest shares for Idaho's spring Chinook Salmon fisheries. This table shows that the Clearwater River return’s harvest share is projected to be 3,252 adult fish (darker peach row), the Rapid River return (darker blue row) is projected to be 1,598 fish, and Hells Canyon’s (green row) is projected to be 306 fish. These estimates all are down slightly from last week. When calculating these harvest shares, we assume these fish will experience average survival rates as they migrate between Bonneville and Lower Granite dams. Right now, the survival rates appear to be on the low side; however, now that the Tribes have closed their fisheries in the Columbia River, survival rates should improve. This is something we will keep a close eye on and keep you posted on how it influences harvest shares. 

I have received numerous calls/e-mails asking me if something is going on with the Snake River dams that could explain for lower-than-expected fish counts or counts that vary up and down from one day to the next. For example, adult Chinook counts at McNary Dam (last Dam on the Columbia before fish turn up the Snake River) through May 22 were 32,245 whereas counts at Ice Harbor Dam (first dam on Snake) were 17,772. Some of the fish passing over McNary will continue on up the Columbia River, but the vast majority are destined for Idaho. That means there is a lot (potentially over 10,000) of Idaho bound fish somewhere between these two dams. Several things can explain why we are seeing some of these things. The main issue is the high dirty water we are experiencing. With flows peaking at over 200,000 cfs, it can become difficult for fish to find the ladders amongst the crazy back eddies and extreme turbulence that occurs below the dams. Often adjustments can be made to how the water is released from the dams to improve passage, but with this much water, there is often little that can be done. Second, we are seeing some extreme flow fluctuations (up to 80,000 cfs in 12 hrs) that have to be confusing for fish. Finally, a transformer went out at Little Goose Dam (third dam up from Snake mouth). This meant the Corp had to shut down some of the Turbines while fixes are being made to the transformer. Currently, two of the turbines are shut down which has created flow patterns below the dams that can be confusing to the fish. Bottom line, it will likely take longer for fish to find their way through the Snake River dams and result in a prolonged migration of fish into Idaho. Another possibility is once flows drop to a certain level, dam passage will suddenly improve and a large surge of fish will push past the dams. This is something to keep an eye on, especially if you like to fish in the lower Clearwater River.

FISHERIES

Clearwater River Basin Fishery

Last week we estimated that 82 adult Chinook Salmon were harvested in the lower Clearwater River (see Table below). Catch rates were pretty slow at about 50 hours a fish, but that is to be expected early in the season. Right now, the Clearwater River is running brown due to severe thunderstorms we recently had. However, flows in the lower Clearwater are forecasted to drop to around 40,000 cfs by this weekend which should provide some good fishing conditions. Just how good the fishing gets is dependent on how many fish are able to navigate past the Snake River dams.

Rapid River Run Fishery

We did not observe any fish being harvested in the lower Salmon or Little Salmon rivers last week which is not surprising seeing how high (74,000 cfs) and dirty the water was. Flows in the lower Salmon River are supposed to remain above 60,000 cfs for another week, which will greatly restrict how many fish make it into the fishery. It looks like we may have to wait until June before this fishery kicks in gear. 

Hells Canyon Fishery

We actually talked to a couple anglers with fish below Hells Canyon Dam last week and estimated that a total of four fish were harvested. Fishing will likely improve some, but all the dirty water coming out of the Salmon River will likely slow fish migration into this fishery. 

That is all I have for you this week.

Have a great rest of your week.