Status of Idaho’s Steelhead Run
Hi everybody. I’ve been getting lots of e-mails and calls asking me what the steelhead run is looking like this year and what we can expect in the future. So, I figured it was time to give you all an update.
This particular update is going to focus on Idaho’s hatchery returns as they are the ones that provide us our fisheries and these are the fish most people are asking me about. I will provide an update on our wild runs later in the year. I am going to break this update down into two sections. One will focus on the hatchery steelhead that are returning to the Salmon River and Snake River upstream of the Salmon (A-run populations) and the other will focus on the Clearwater River return (B-run population).
A-Run Populations (Upper Salmon River and Snake River)
For those of you who have been tracking the dam counts, you are probably aware that this year’s steelhead counts at Bonneville Dam are starting out slow once again (33% of 10-year average). However, if we really want to get a good feel for what this means for Idaho, we have to look at the PIT tagged fish that are being detected at Bonneville Dam. The graph below summarizes the number of hatchery steelhead (using PIT tag data) bound for the Salmon River and Snake River (upstream of the Salmon) that have passed over Bonneville since 2010. Once thing we can do with this data is compare how the run this year (red line) compares to previous years. If we look at this year’s return (up through July 30 as indicated by the vertical white dashed line), we can see that only two other years have had a slower start (last year and 2015). However, the run is still early which means there is still a lot of uncertainty on what we can expect in the future. For example, the graph shows that in some years the run can start out strong and then end up relatively weak (like 2016), whereas in other years the run can start relatively week and end up strong (like 2011). With so much uncertainty, it is difficult to forecast the future at this point. To show you what I mean, I have actually calculated a run forecast base on different run timings. If this year’s run follows the average run timing we have seen since 2010 (dotted red line), we will end up with a poor run like we saw last year. If the run timing follows what occurred last year, which was one of the latest on record, we could have an excellent run (dashed red line). Obviously a forecast that projects that the run could be anywhere from good to poor is not very useful. However, if the run falls within the range shown on the graph, this is enough to provide harvest fisheries. If I had to summarize this information in one sentence, I would say the run is starting out slow, but it is early enough to be hopeful.
B-Run Population (Clearwater River)
Because most steelhead bound for the Clearwater River don’t pass over Bonneville Dam until after September 1, we really can’t say how the run is doing because it hasn’t even started yet. In fact, only one Clearwater bound PIT tagged hatchery steelhead has passed over Bonneville Dam to date. The best I can do for you is to project what this run might look like based on what we saw last year. Because most of the hatchery steelhead that return to the Clearwater River spend two years in the ocean, we can predict how many 2-ocean fish will return this year based on the number of 1-ocean steelhead that returned last year. On average, what we have experienced is that about 6 times as many 2-ocean fish return as the number of 1-ocean fish that returned the previous year. The graph below shows this relationship. The exciting thing is last year we had a really good return of 1-ocean hatchery fish to the Clearwater (about 5,000 fish). Based on this good 1-ocean return last year, this model forecasts over 30,000 2-ocean hatchery fish will return to the Clearwater this year (red diamond). I can’t say I have a lot of faith in this estimate, especially after just experiencing a poor Chinook Salmon return. However, I do feel the return will be large enough that we won’t need to implement rule restriction to assure we meet brood needs. As always, only time will tell.
Finally, I need to mention that starting August 1 (tomorrow), the steelhead harvest season will start in the Clearwater River below Memorial Bridge (two clipped fish a day). Since June 15, we have had a little over 1,000 steelhead pass over Lower Granite Dam. Because I am into graphs, I had to produce one to show how these counts compare to the past. I have been getting reports of a few steelhead being caught in the catch-and-release fishery, but catch rates have been relatively slow.
That is all I have for you today. I will keep you informed as we learn more and/or if we feel it is necessary to make any rule changes. Until then, enjoy your summer.
Clearwater Region’s Fisheries Manager