Salmon are thriving after Klamath River dam removals, study finds

Salmon return fast after Klamath dams come down

Chinook are reclaiming historical habitat faster than researchers expected.

Rewilding the upper Klamath River Basin: rapid recolonization of Chinook salmon following the world’s largest dam removal

Habitat fragmentation is a global driver of decline in biodiversity, yet evaluations of ecological response following re-connection remain rare. In 2024, four hydroelectric dams on the Klamath River were removed, reconnecting over 640 km of anadromous habitat and marking the largest dam removal project completed to date. We used a stationary high-resolution multi-beam imaging SONAR to quantify adult Chinook salmon (Oncorhynchus tshawytscha) passage into newly reopened reaches during the first two migratory seasons following dam removal. An estimated 7,742 (95% CI: 7,702–7,778) Chinook salmon migrated upstream in 2024 and 13,310 (95% CI: 12,876–13,733) in 2025, representing 18–19% of fish returning to the Klamath River Basin. Within this period, Chinook salmon recolonized 88% of their documented historical distribution, expanding into 345 km of reconnected habitats and reaching elevations of up to 1,250 m. Recolonization required fish to swim through dam removal sites, complex hydraulic corridors and engineered fishways, demonstrating the propensity for rapid recolonization at basin scale despite these challenges. These findings provide the first quantitative assessment of salmon response to the world’s largest dam removal and demonstrate how reconnection can catalyze large-scale recolonization in historically fragmented river networks.

Salmon are thriving after Klamath River dam removals, study finds

OLYMPIA — The Klamath River, cleared of big barriers for the first time in more than a century after the largest dam removal project in American history, is experiencing a significant rebound of native chinook salmon, according to a new study.

Removal Of Klamath Dams Frees The Salmon To Return In Large Numbers To Historical Breeding Grounds In Southern Oregon | The Ashland Chronicle-Oregon

Why it matters: Salmon are returning to their historical breeding grounds far faster than tribes, researchers and conservationists expected, per a new study.

Klamath Salmon Have Reclaimed 88 Percent of Their Historic Range Less Than Two Years After the Dams Came Down

Less than two years after the last of four dams came down on the Klamath River, Chinook salmon have reclaimed 88 percent of the historical range they were locked out of for more than a century. A peer-reviewed study, published in Scientific Reports and led by CalTrout with the Yurok, Karuk and Klamath tribes and …

The Salmon Came Back: New Published Study Confirms Rapid Chinook Return in the Klamath River After the World’s Largest Dam Removal

Less than two years ago, four dams on the Klamath River were removed. This week, the first peer-reviewed science is out — published in Scientific Reports, confirming that Chinook salmon reoccupied 88% of their historical range within just two migratory seasons.