HOOD RIVER — With modern technology, biologists can follow the entire life of salmon over years in the Hood River — learning, they hope, what part of the river it was born in, where it lives as a tiny fry, how much it grows over the summer, where it returns to spawn as an adult, and with luck how many of its children survive and who their fathers were.
The new program’s just getting started, with a single year of data.
Assistant district fish biologist Lindsay Powell gave the Hood River Watershed group an update on salmon and steelhead populations here, where multiple restoration projects are in progress or newly finished, on March 31. Powell is employed by Oregon Department of Fish and Wildlife.
The Hood River is made up of three forks flowing from the northwestern to eastern side of Mt. Hood. The primary migrant fish is steelhead, but there’s also a few coho salmon, fall chinook, and an extinct population of spring chinook, which scientists are trying to re-start with hatchery production.
Also present are bull trout, cutthroat trout, rainbow trout and mountain whitefish; Pacific lamprey, sculpin, and suckers.
Before 2010, migrating fish were blocked from the upper Hood River by Powerdale Dam. This dam previously included an adult fish trap; here all the salmonids were snapped up, counted, and some of them selectively passed upstream. The dam’s removal is “probably the most important restoration action that has occurred in the Hood River,” Powell said. “But the other thing that happened when Powerdale was removed was we lost the ability to capture adult fish” and count them.
Now they rely on catching fish in screw traps, counting them, releasing them, and calculating population estimates. They’ve tried a channel-spawning weir, but that was hard to operate in the spring floods and still didn’t get a good count.
Even screw trap estimates “haven’t been very reliable,” Powell said. There’s so few wild salmon here, she can’t get a big enough sample size.
These traps also count out-migrating youngsters on their way to the sea.
Monitoring efforts over the years include a Bonneville Power Administration program formed in 1991 in an attempt to mitigate for the hydropower dams which then cut off fish migration routes. Master plans are released now and then, the last in 2008. The program ended in 2021, leaving a two-year gap in the data before the Hood River Basin Partnership got a $10 million Focus Investment Partnership grant to continue work through 2030. The grant-funded labor is, in part, to find out how fish are using the restored areas.
Warm Springs Indian Reservation also monitors and studies the basin’s fish.
Steelhead in this river are listed under the Endangered Species Act, with a few summer steelhead and a larger winter run. Wild winter steelhead numbers in the river vary, but generally stand below 1,000 fish. Fewer than 300 summer steelhead return.
Summer steelhead hatchery production ended in 2008, when research showed it was “important to minimize the proportion of hatchery origin spawns with wild fish,” Powell said. In other words, too many domesticated steelhead were mating with their wild relatives.
The winter run is more abundant, and hatchery production there lasted until 2021, when it ended partly because of funding, and partly because of the same concerns about interbreeding.
Spring chinook were extinct in the Hood River since the 1970s. Now an experimental population is being re-introduced using a hatchery. Up to 250,000 smelts are release annually. Less than 100 wild fish return, but many more from hatcheries — an estimated 3,200 in 2025.
“Part of the reintroduction effort is to restart wild production. But overall, you can see that that really hasn’t been accomplished very well, because we just have consistent low abundance of wild spring chinook,” Powell said. The abundance of hatchery chinook is “enormously greater.”
Most of Powell’s work involves PIT tags — much like pet microchips.
A special array of antennae on the West Fork pick up signals from PIT tags, tracking how many spawning fish use restored areas. This year they counted 316 spawners on and near a West Fork restoration site, mostly hatchery fish introduced to restart the extirpated chinook run.
They’ll partner with Warm Springs on a genetic study, taking a sample from each PIT-tagged adult so they can see how many of its eggs return as adults next year, and learn where the most successful spawning grounds are. They’ve already got genetic samples from 330 fish ready to go.
They are studying whether restoration projects are working for salmon by estimating out-migrant abundance from the project areas. This shows where spawners are having the most reproductive success in the West Fork Hood River.
There’s data on out-migrant abundance going back to 1994 through BPA’s now-dead Hood River Research Program.
Steelhead numbers have been stable. Again, they haven’t been able to estimate a number for salmon because the sample size is so small.
What that means is that, again, wild chinook numbers are really low. Coho are less well-studied, but anecdotally, staff have been seeing an increase in tiny coho in the screw traps, Powell said.
Powell’s team counts the tiniest fish, just born and rearing in leafy corners of restored flood-plain, using electro fishing. They walk backpack electro-fishing units down the bank, catch the stunned fish, count them, release them, and do it again — and again — and again — hundreds of times at each site. They also use this trick to see how much smolts grow during their residence in the river, again using PIT tags.
All that takes a lot of partnerships with private landowners on the lower East Fork.
“It’s a little bit hard to really say a lot about what these results mean, because this is just the first year of the sampling,” Powell said.
Funding extends through 2030.
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