Press Release

Clearwater Region Chinook Update (5/11/18)

Weekly insight into Idaho's salmon runs.

Message from Fisheries Manager, Joe DuPont

Run Size 

Since I talked to you last week, we have seen counts of adult Chinook Salmon over Bonneville Dam pick up considerably only to drop back down.  The counts were actually fairly exciting for five days and brought us up from the 6th worst count ever at Bonneville (out of 80 years) to the 22nd worst.  So, I would say things are looking much better.  

I have put together a couple of graphs for you below to give you a feel for how counts are progressing at Bonneville Dam.  What is interesting is how closely this year’s counts are tracking to what occurred last year.  Not only is the run definitely late, but just like last year, we saw a sudden spike in salmon counts followed by a marked decline (see second graph).  As I indicated last week, I was expecting this with flows over Bonneville Dam projected to pick up.  

The third graph below compares last year’s flow data (gage height) below Bonneville Dam (USS 14128870) to this year’s.  This data suggests that once flows exceed a gage height of about 28 (about 420,000 cfs) it starts impeding fishing passage (indicated by red dotted line on graph).  Unfortunately, flows are projected to remain above this level for at least the next week, so daily counts below 2,000 may be the norm for a while.  

Some good news is NOAA fisheries reported that only 18% of the Chinook Salmon they tagged in their test netting in the lower Columbia have shown up at Bonneville Dam or Willamette Falls.  This suggests there still are a lot of fish waiting to make their way upstream.

Adult chinook counted at Bonneville Dam
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Joe DuPont, IDFG

Daily counts of Adult Chinook over Bonneville Dam
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Joe DuPont, IDFG

Columbia River flows below Bonneville Dam
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Joe DuPont, IDFG

What about salmon runs destined for Idaho?

If you are wondering how the runs of Chinook Salmon destined for Idaho are doing, I can tell you that this year’s Rapid River run is about the same as we observed in 2017 and the Clearwater River run is actually looking better this year.  I created yet another graph for you below to show what the Rapid River and Clearwater River runs are looking like based on PIT-tags that have passed over Bonneville Dam.  Right now, it is difficult to tell what our harvest share will be for these different runs because their timing appears unusually late making it hard to predict, and we don’t know how the delay in passage over Bonneville Dam will ultimately influence their survival.

Number of Idaho Bound Adult Chinook  over Bonneville
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Joe DuPont, IDFG

Fisheries

We still haven’t documented any harvest in Idaho yet which isn’t too surprising seeing the Clearwater River has been high, dirty, and full of debris this week.  Flows are supposed to drop some this weekend, so maybe we will see our first fish harvested then.  Counts over Lower Granite Dam are still low (369 fish), so I don’t expect much to happen.  If you are wondering when to start fishing, the pulse of Chinook Salmon that passed over Bonneville Dam this week will likely start hitting Idaho in about 2 weeks (depending on flows).

That is all I have for you today. Have a good weekend, and I will talk with you next week.

Joe DuPont
Clearwater Region Fisheries Manager