The final Deschutes Fisheries Workshop presentation that I will dive into was a report on fish population in Whychus Creek. It was “shocking” in the words of one fisheries biologist. I agree and had to go over the data again with the presenter to make sure I understood what was being said, which I did yesterday. Here’s the presentation. Keep reading for a discussion of what it says and some background that gives important context.

When Portland General Electric renewed their license to operate the Pelton Round Butte hydroelectric facility it came with a number of requirements, including reintroducing some anadromous fish populations above PRB. Along with fish passage, successful reintroduction was thought to require habitat restoration and removal of other barriers. Numerous government agencies, NGOs, and individuals have worked hard for many years on these tasks, and continue to do so.

Most believed that Whychus Creek represented the best opportunity for creating spawning habitat for summer steelhead and spring chinook. The Deschutes Land Trust, Deschutes River Conservancy, and the Upper Deschutes Watershed Council created a partnership, assisted by PGE, the Oregon Watershed Enhancement Board, Oregon Depart of Fish & Wildlife, US Forest Service, and others, to restore Whychus Creek via habitat restoration and increased streamflow. Significant sums of money have been, and continue to be, spent on this effort. Unfortunately, anadromous fish have mostly had other ideas and few returning adults have chosen Whychus Creek as their final destination.

This has been disappointing but the thought has been that improved habitat and increased flows will benefit wild, native redband trout. Clearly, this too would be a worthy outcome. Unfortunately, this does not seem to have occurred, at least so far.

The presentation is somewhat dense, so here are some highlights:

• Page 8: “Floodplain” is a restoration project upstream from Sisters primarily lead by the US Forest Service. It is important to keep in mind that hundreds of thousands of steelhead and chinook hatchery fry were released into Whychus Creek from 2007 until 2018. Before 2014, sampled fish were 100% redband trout (RB), a large portion of which were undoubtedly planted steelhead fry. After 2016 there were also some spring chinook (CHS) fry. Sampling in 2022 showed that RB numbers decreased while brown trout (BR) and brook trout (BT) appeared. BR and BT are invasive species in Whychus Creek. CHS disappeared in the 2022 sampling as fry releases had been discontinued and any planted smolts had outmigrated by the time the survey was done in the fall.
• Page 9: Further downstream at the Whychus Canyon Project, the survey numbers are even more surprising. Non-native brown trout have been present in the lower parts of Whychus Creek for some time but last year they dominated the survey. Redbands were reduced to only 11% of the population.
• Pages 14 & 16: Redbands in Whychus Creek are very small. 70mm is about 2.8 inches. There were bigger redband trout in 2016 & 2018, but these were most likely hatchery steelhead fry which were fed a lot before being released in the creek. In 2022, there were a few bigger fish, but the numbers overall were very low.
• Page 25: A summary of conclusions. Redband numbers are low. Habitat projects have not increased their population and “recruitment” (think natural reproduction and early survival) is low. Conversely, brown trout are increasing.

Clearly, the big question is why? There is no definitive answer but there are some interesting hypotheses. My immediate thought was that fry stocking created an abundant food source for brown trout. Fish biologists at the workshop and afterwards told me they had the same thought. This may be the case, but stomach samples taken from a few brown trout did not provide confirmation.

Drought conditions could have played a role, but this would have had an impact on brown trout as well as redbands. There may be an issue with fine sediments covering eggs in the spring.

What seems to me* to be the most plausible hypothesis is that the hundreds of thousands of steelhead fry released into the creek simply occupied too much of the habitat and ate most of the available food, depressing the native redband trout population. Hatchery steelhead fry are well fed and would be bigger than wild redband fry when released (“liberated” using fisheries terminology), so the hatchery fish may have left little food or cover for wild, native fish. If so, now that fry stocking has ceased, there could be an increase in the redband population in the future as they mature and spawn.

Regardless, after so much time, effort, and money has been put into Whychus Creek, it truly is shocking how few adult steelhead and chinook have returned to spawn and how poorly the wild, native redband trout population is fairing. It also once again points to the importance of the Crooked River. The Crooked is where most anadromous fish want to go and contains a viable redband population in some stretches. It also needs lots of help. Finally, this is yet another cautionary tale of people attempting to influence or guide nature without sufficient understanding of how to do it.

*Please note that I am not a fish biologist, I only play one in this blog. 🙂