Spring Chinook Salmon Fishery Update (5/11/2021)
Rapid River Run, Hells Canyon, and Clearwater River Fisheries
Hi everybody, it is time for my weekly spring Chinook Salmon update (5/11/2020). So let’s get right to it and discuss what we have learned since my last update.
As of yesterday (May 10, 2021), 37,320 adult Chinook Salmon had passed over Bonneville Dam this spring season which is about 45% of the 10-year average. During my last update (5/4/21), we were at about 50% of the 10-year average. The reason for this drop is because counts of adult spring Chinook Salmon at Bonneville Dam are tapering off. The figure below clearly shows how daily counts at Bonneville Dam this year (red line) have steadily declined since they peaked at over 4,500 fish in late April. This is not a good sign as it suggest that we have seen the peak and most of the spring run has passed over Bonneville Dam. We were hoping the run timing was a little late, but this data is suggesting the run may actually be a little early. To expect another surge of fish at this point, we would want to see high and/or dirty flows that could explain for a delayed migration. However, flows in the Columbia River have been average to below average lately.
To better understand how many hatchery salmon passing over Bonneville Dam are destined for Idaho, we need to look at PIT tag detections. The table below summarizes this data. If you are following this information closely, you will notice that the harvest share totals (fourth column) for all three fisheries have declined since my update last week. These harvest shares were calculated assuming the fish have an average run timing over Bonneville Dam. The declining harvest shares is yet another piece of information suggesting the run timing is a little early. At this point it looks like 75-80% of the Rapid River bound fish have passed over Bonneville Dam. If the run is 80% complete, you can expect our harvest shares to decrease. If we are closer to 75%, our harvest share should remain the same or slightly increase.
Last week I mentioned that we were seeing improvements in the Clearwater River return and were hoping counts would continue to improve so that we could open a fishery there. However, as you can see in the table above, our estimates indicate there will be no available harvest share unless things turn around dramatically. We will keep a close eye on this information and keep you posted if any new developments occur.
We observed a few more anglers salmon fishing last week, but still we have not talked to anybody who has harvested a salmon. I think that will all change this week as it appears counts over Lower Granite Dam peaked on Sunday and Monday (over 1,400 fish each day). With the lower than average flows we are experiencing in the Snake and Salmon rivers, many of these fish will likely make it to the lower Salmon River this weekend. I do want to remind you that if the harvest share for the Rapid River run fishery ends up at 600-900 adult fish, the fishery will likely only remain open two or three weeks once the fish get there. Our goals is to divide up the harvest so half occurs in the Salmon River and half occurs in the Little Salmon River.
That is all I have for you until next week’s update. I hope you all have a good week.