California's historic dam removal notches another big win for salmon

When four dams were torn down along the California-Oregon border two years ago, scientists were stunned by the large numbers of salmon that moved so quickly up the newly unobstructed Klamath River.

This month brought another striking development.

A Chinook salmon was detected going up the river in Oregon, past the former dam sites, and it was not part of the fall run of fish that's already been racing up the Klamath in late summer and in early fall. It was a much rarer fish: a spring-run salmon, which migrates earlier in the year and has long struggled to survive on the West Coast.

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The Oregon Department of Fish and Wildlife's detection of the first spring-run salmon swimming into the upper Klamath Basin in more than a century suggests that this imperiled fish run has begun to reap the benefits of dam removal.

The success of the run, on top of the fall run, stands to increase the prevalence, diversity and resilience of struggling West Coast salmon. Salmon have seen their numbers drop dramatically over the past 100 years as the rivers they depend on have shrunk, gotten warmer and been blocked by dams. A hotter, drier future with a changing climate will only make things tougher.

"If you think about the spring Chinook, we don't have many, so it's just incredible to have them make it up here," said William E. Ray Jr., chair of the Klamath Tribes, one of the native groups along the river, which has its tribal headquarters in the upper basin community of Chiloquin, Ore. "The fish had to go through so much. I don't think we're fully taking into account what a Herculean effort this is."

Chinook salmon, also known as king salmon, have a remarkable, yet precarious, migration. Success relies on a lot going right across myriad bodies of water. The fish hatch in freshwater rivers and streams but swim to the ocean for about two to three years, where they grow. Then they return to their birthplace to create the next generation before dying.

The $500 million dam demolition on the Klamath River, the largest dam-removal project in U.S. history, was initiated by tribal communities looking to clear a major bottleneck for salmon. Opening up hundreds of miles of previously inaccessible waterways is expected to increase their spawning and ultimately their population.

The Klamath River, which winds 250 miles from southern Oregon through Northern California to the Pacific, once had the third-largest number of salmon in the continental U.S. The Columbia and Sacramento rivers have boasted more.

The spring-run salmon that recently made it to the upper Klamath Basin has been identified by Oregon wildlife officials as a hatchery fish, meaning it wasn't reared naturally in the river but in captivity.

Wildlife officials trace the fish to an experimental release of captive-bred salmon three years ago, made by the Oregon Department of Fish and Wildlife in the upper Klamath Basin before dam removal. The fish were released to test how salmon might fare in the upper basin after the dams came out.

Interestingly, the spring-run fish, which was outfitted with an electronic tracking tag, swam downriver from the upper basin through the former dam sites in May of 2024, just as the dams were being demolished, officials say. Department officials didn't pay much attention to the fate of the fish at the time because their focus was on learning about salmon movement upriver.

On June 3 of this year, however, the tagged salmon was back on the agency's radar when its signal was unexpectedly detected, indicating it was moving back up the Klamath River. Officials tracked its migration upriver, through two dams in Oregon that remain on the river, which salmon can bypass with fish ladders, to the mouth of the Williamson River on Oregon's Upper Klamath Lake.

While wildlife officials say it's possible the tagged fish spent the past two to three years on the lower reaches of the Klamath River, they told the Chronicle that it's highly likely the fish migrated all the way to the ocean and back, revealing the potential of spring-run salmon to navigate the entire river. The agency doesn't monitor salmon in the lower Klamath. It's also possible there will be more spring-run fish making the round trip, though the upstream migration generally ends in July.

Wild spring-run salmon also live on the river, but they have not been observed moving through the footprints of the old dams. This is perhaps because their numbers are so small that the lower basin is sufficient to support them, and instinct has kept them returning to the waters where they were born. In contrast, the larger fall-run population has had members straying upriver.

There are also challenges upriver, including turbid waters left from dam demolition, which are improving, and the existing Keno and Link River dams, which can be difficult to pass even with fish ladders.

Federal, state and tribal scientists have long planned to intervene to help spring-run fish. Earlier this year, the Oregon Department of Fish and Wildlife, Klamath Tribes and Yurok Tribe were awarded a $6 million federal grant to incubate spring-run salmon and begin a reintroduction program in the upper basin.

"It might take a few decades, but there will be a fishable population again," said Ray Jr., the Klamath Tribes chair. "The (recently detected) spring-run Chinook gives us hope."

The milestone for spring-run fish on the Klamath comes as the more populous fall-run is dealt a setback.

The U.S. Fish and Wildlife Service reported this month that many out-migrating fall-run salmon succumbed to the fish parasite C. shasta. This naturally occurring parasite thrives in warm, low-running river flows, which have characterized the Klamath this year, as high temperatures and very little snowfall have plagued the basin.

While federal officials say nearly one in five juvenile fish was detected with fatal levels of C. shasta, the problem appears to be mostly confined to a hatchery population of salmon, averting catastrophe for the fall run.

"The wild-born fish got out of the system before the disease became bad," said Craig Tucker, a natural resources policy consultant for Northern California's Karuk Tribe.

The concern that remains, Tucker said, is how low and warm the Klamath will get later this summer when the adult fall-run fish return. He said many of these fish will likely struggle to spawn due to the poor river conditions.

Tucker also said the challenges for the fall-run salmon underscore the importance of securing a successful spring-run.

"If you imagine in years like this one, spring fish come back in April or May and get upstream as far as they can, then it gives you a distribution of fish in a much bigger area of the basin," he said. "The way salmon survive is by having a lot of life-history variation."

The Yurok Tribe in Northern California similarly praised the detection of the spring-run fish as a good omen for salmon.

"The return of the first spring-run salmon to the upper basin is extremely encouraging," said Barry McCovey, Yurok fisheries department director, in a statement to the Chronicle. "It signals strong potential for planned efforts to accelerate the recovery."

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This story was originally published June 30, 2026 at 10:37 AM.