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Spring Chinook Salmon Fishery Update

by Idaho Fish & Game
EIN Presswire, May 25, 2021

A spring chinook salmon in hand of happy fisherman. Rapid River Run, Hells Canyon, and Clearwater River Fisheries
Run Update

Hi everybody, it is time for my weekly spring Chinook Salmon update (5/25/2021). Yes, that is a picture of me. After not fishing for spring Chinook Salmon at all last year, I had to make sure I got out a least a couple days this year. Be sure to read the "fisheries" section below as it indicates when closures are occurring and which fisheries will be open.

As of yesterday (May 24, 2021), 60,240 adult Chinook Salmon had passed over Bonneville Dam this spring season. This is about 53% of the 10-year average. Since my last update (5/18/21), counts at Bonneville Dam have dropped fairly steadily (see red line in figure below). We did see a little bump yesterday, but at this point it looks like the spring Chinook Salmon run over Bonneville Dam is about over. This means if we see any larger peaks in the future, it would likely be for summer run fish destined for places other than Rapid River, Clearwater River or Hells Canyon. To date, this spring return is better than the past two years, but outside of that, you would have to go back to 1999 before you would find another spring return with lower counts at Bonneville Dam.

To better understand what this means for harvest shares for our fisheries, let see what the PIT tags are telling us (see fourth column in Table below). Since last week, our estimated harvest shares have gone down for all three spring Chinook Salmon fisheries in Idaho. The Rapid River run harvest share is now at 966 fish, the Hells Canyon fishery is at 154 fish, and the Clearwater River run is at 185 fish. Remember, these are just estimates, and they can change depending on how many more PIT tagged fish destined for these fisheries pass over Bonneville Dam and how many of these fish make their migration to Idaho (past Lower Granite Dam). Final harvest shares are set based on how many fish make it past Lower Granite Dam.

I do need to make you aware that there is a possibility that harvest shares could increase for the Rapid River Run fishery. The reason for this is each year we collect genetic data at Lower Granite Dam to help us better understand how well the PIT-tagged fish are representing the actual return size. On average, PIT-tagged fish represent about 70% of the actual return. For example, if the real return was 1,000 fish, PIT-tagged fish on average would indicate the return was 700 fish. This underrepresentation is actually good as it helps ensure we make our broodstock needs because not all unharvested fish will make it to the hatchery trap due to straying and natural mortality. However, what we have learned from this analysis is occasionally PIT-tagged fish have represented a much lower percent of the return - we have seen it as low as 45% in the past. On years when the PIT-tagged fish represent much lower than 70% of the return, we can increase harvest shares and still be confident we will make our broodstock needs. I'm telling you all this because we are in the process of analyzing this data and should have the results in next week, and I didn't want you to be thinking we were hiding something from you if we suddenly increased our harvest share. I will let you know next week what we learned from this analysis.


Rapid River Return

We estimated that 270 fish were harvested in this fishery last week with the vast majority (all but 17) being caught in the lower Salmon River (see table below). The most harvest and highest catch rates (15 hrs/fish) occurred in Section 2 of the lower Salmon River (Time Zone Bridge to Shorts Creek). This brings the total harvest (including catch-and-release mortality) in the lower Salmon River to 409 fish. That means we have fewer than 100 fish to go before the lower Salmon River reaches its quota of 50% of the harvest share. For this reason, we will provide two more days of fishing on the lower Salmon River (Thursday and Friday) and then close it on the end of fishing hours on Friday May 28, 2021. After that date, only the Little Salmon River will remain open. I suspect fishing in the Little Salmon River will pick up greatly this week.

Hells Canyon

We estimate that 46 adult Chinook Salmon were caught below Hells Canyon Dam last week. That brings our total estimated harvest to 50 adult fish. The highest catch rates we observed in all of the open fisheries last week actually occurred below Hells Canyon Dam (11 hrs/fish). Part of the reason for this is fishing effort was really light. Most of the people we talked to had harvested a fish. The Hells Canyon harvest share is currently at 154 fish meaning we have over 100 to go before we have to shut this fishery down. However, we will start trapping below Hells Canyon Dam next Tuesday (June 1), which means catch rates should drop at that point. So, if you like to fish below Hells Canyon Dam, this week is a good time to go.

Clearwater River Return

I know a lot of people are wondering whether we are going to open a fishery in the Clearwater River basin. Right now our harvest share is at 185 adult fish. In the past, we have said we would open an adult Chinook Salmon fishery in the Clearwater basin when returns were large enough to provide a harvest share greater than 200 adult fish. If the return is lower than that, we could open up a jacks-only fishery if the jack return was large enough and we had at least 50 adult fish in our harvest share. We haven't seen a PIT-tagged Clearwater River bound hatchery fish pass over Bonneville Dam in the last three days, so it doesn't seem like the adult harvest share will go up. Initially, the jack return was looking promising, but we have only seen one PIT-tagged jack pass over Bonneville Dam since May 16. This information suggest our jack harvest share could end up around 500 fish. Our Commission will be meeting on June 3, and will take this opportunity to review the data to determine what type of, if any, fishery we can open in the Clearwater River basin. I know that the longer we wait the more fish push upstream limiting where people can successfully catch fish. Unfortunately, when we are right on the edge of having enough fish to provide a fishery, it is necessary to wait. So, you will have to stay tuned until next week (June 3) for that decision.

That is all I have for you until next week's update. Good luck fishing!

Idaho Fish & Game
Spring Chinook Salmon Fishery Update
EIN Presswire, May 25, 2021

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