Four dams came down. The salmon went 360 miles upstream.
The Klamath's 2025 Chinook run came in at 51,277 fish against a forecast of 28,554 — and the reason is less about fish ladders than about water temperature.
In short
What happened. An estimated 51,277 adult fall-run Chinook salmon returned to the Klamath basin in 2025, against a forecast of 28,554.
What it means. Four dams came out between 2023 and 2024, and salmon have since spawned over 360 river miles upstream, in reaches closed to them for about a century. The run was still 61% of the 48-year average.
Risks and impact. Removal reopened about 420 miles of habitat and changed the river’s temperature pattern, shortening the time young fish are exposed to a parasite that kills them. In June 2026 the Karuk Tribe and the US Fish and Wildlife Service reported elevated parasite levels during low flows. Commercial salmon fishing here has not run since 2022.
What can be done. The counts come from the California Department of Fish and Wildlife, which reports them at an annual salmon meeting; NOAA Fisheries, California Trout and the basin tribes publish their own monitoring.
What to watch. Whether returns above the former Iron Gate Dam hold or grow. NOAA expects established upstream populations to take ten to fifteen years.
Shown as a summary because of your reading settings.
What happened
On 25 February 2026, at its annual Salmon Information Meeting, the California Department of Fish and Wildlife put a figure on the previous autumn. An estimated 51,277 adult fall-run Chinook salmon returned to the Klamath basin in 2025. The pre-season forecast had been 28,554.
Of those, 39,860 were natural-origin fish heading for river gravel rather than a hatchery — 205% of the 19,417 predicted. A further 18,574 jacks came back, against 7,085 in 2024. Jacks are young males that return a year early; biologists read their numbers as a rough signal for next season.
The fish also went where they had not been. CDFW counted 11,722 adults and 341 jacks above the former Iron Gate Dam. Four dams were taken out of the Klamath between 2023 and 2024, the last barrier on 26 September 2024. NOAA Fisheries, which calls it the world’s largest dam removal effort, put the reopened habitat at about 420 miles.
California Trout, coordinating monitoring with more than 19 partner organisations, recorded salmon over 360 river miles upstream, spawning in the Wood, Williamson and Sprague rivers. More than 10,000 fish over two feet long passed the old Iron Gate site in autumn 2025, roughly 30% more than in 2024, and arriving weeks earlier.
The run was still only 61% of the 48-year average.
The background
The obvious thing a dam does to a salmon is stand in the way. That was never the whole problem.
A reservoir is a river made to sit still. Still water absorbs summer heat and holds it. It also concentrates blue-green algae, blocking the sunlight the river would otherwise use to shed that heat overnight. So a dammed river runs warm exactly when salmon need it cool, and it flattens the daily temperature swing fish use as a cue to move and spawn.
Measurements since removal show that changing. Monitoring by the contractor Resource Environmental Solutions, alongside CDFW and the Klamath River Renewal Corporation, found the river reaching 50°F about a month earlier in spring across 2024 and 2025 than in 2023, and cooling about a month earlier in autumn. The average daily temperature swing rose from roughly 1.75°F to around 5°F. Naturally cold springs became reachable for the first time in over a century.
That matters mechanically. Cooler water earlier in the year lets juvenile salmon grow faster and leave for the sea sooner. A shorter stay in the river means less exposure to Ceratonova shasta, a parasite that kills young fish here.
Which brings the honest part. In June 2026 the Karuk Tribe and the US Fish and Wildlife Service reported elevated C. shasta levels during the 2026 water year, driven by historically low flows and warm conditions. “Dam removal gave the Klamath River and our fish a fighting chance,” said Kenneth Brink, the tribe’s vice-chairman. “But no one should confuse dam removal with an instant cure.” The tribe’s senior biologist, Toz Soto, said the science was saying two things at once: salmon are using their historic range, and this year’s conditions were hard on young fish.
NOAA’s own expectation is that established upstream populations take ten to fifteen years — several salmon generations. Commercial salmon fishing on the Klamath has not run since 2022.
Who it touches
Some of the work looks nothing like fisheries science. The Yurok Tribe’s revegetation crew hand-sows seed across the drained reservoir beds — roughly 150 acres in the tributary restoration alone. A single January’s planting used more than 16,000 pounds of native seed mixes, 76,000 tree, shrub and grass plugs, 25,000 acorns and 2,500 milkweed starts. It is a five-year project, with more going in each spring.
Ben Hunsucker, a Yurok citizen and long-serving crew member, described the first morning back at work: an otter, eagles and waterfowl at the river’s edge. Joshua Chenoweth, the senior riparian biologist, said he was happy with the volume and diversity of healthy plants.
The 2025 run also permitted a harvest. Tribal fisheries took 3,493 adult fish — 1,322 by the Yurok, 2,171 by the Hoopa Valley Tribe — against an allocation of 1,385.
The deeper story
The Klamath is an unusual engineering story, because the engineering consisted of subtraction.
Most environmental repair is additive. We build a fish ladder, a treatment plant, a hatchery, a wall. That suits us: a structure can be photographed, costed, opened by an official and pointed at for decades. Removal produces nothing to point at. The finished product of the world’s largest dam removal is an absence, plus a river doing what rivers do when nobody is holding them still.
That is awkward for the way people assign value. A solution made of stopping something rarely feels like as much work as a solution made of building something, even when it costs more and takes longer. It is the same instinct that makes a deleted paragraph feel like less effort than a written one.
There is a second difficulty, about scale. The fish are running at 61% of a 48-year average, in a basin they were shut out of for a century. Is that a triumph or a shortfall? The answer depends on which year has quietly been chosen as normal, and nobody in the argument announces their baseline. A person who remembers the 1960s and a person who remembers 2022 are looking at the same 51,277 fish and seeing two different rivers.
Ecologists have a phrase for the slow downward drift in what each generation treats as ordinary. The Klamath is now a test of whether that drift can also run backwards — and of how long a public, or a budget, will wait to find out.
Something to sit with
- Which year do you privately use as the baseline for what a healthy river, or a healthy anything, should look like?
- Why is it harder to fund the removal of something than the building of something?
- Ten to fifteen years is normal for a salmon population and unusual for a news story. What gets lost in the difference?
Sources
- California Department of Fish and Wildlife — Klamath River Chinook salmon reoccupying historic habitat — https://wildlife.ca.gov/News/Archive/klamath-river-chinook-salmon-r...
- Fishing the North Coast — Klamath fall Chinook return tops expectations in 2025 (CDFW Salmon Information Meeting figures) — https://fishingthenorthcoast.com/2026/02/19/klamath-fall-chinook-re...
- California Trout — One year after Klamath dam removal: monitoring results — https://caltrout.org/news/klamath-dam-monitoring-december-2025/
- Save Our Wild Salmon — Klamath River water temperatures responding to dam removal — https://www.wildsalmon.org/news-and-media/news/klamath-river-water-...
- Lost Coast Outpost — Parasites threaten juvenile salmon in the upper Klamath, Karuk Tribe says — https://lostcoastoutpost.com/2026/jun/16/parasites-threaten-juvenil...
- Yurok Tribe — Yurok crew resumes revegetation work behind former Klamath dams — https://www.yuroktribe.org/post/yurok-crew-resumes-revegetation-wor...
- NOAA Fisheries — World's biggest dam removal project to open 420 miles of salmon habitat — https://www.fisheries.noaa.gov/feature-story/worlds-biggest-dam-rem...
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