Chinook salmon have quickly returned to parts of the Klamath River in Southern Oregon and Northern California. Dams built during the 20th century blocked fish from reaching places where they laid eggs. The river’s breeding salmon population fell by about 90%. In 2024, four dams were removed, opening areas that had been blocked for roughly a century.
Shortly afterward, 7,742 Chinook salmon swam upstream past the former dam sites. In 2025, the number rose to more than 13,000. Researchers found that the fish returned to 214 miles, or 345 kilometers, of river. They reached 88% of their known historical habitat. Study first author Damon Goodman expected the fish to return, but their speed and numbers surprised him.
Researchers counted the fish with an underwater camera that uses sound instead of light. It worked even though the river remained muddy after dam removal. Although the return is encouraging, recovery requires successful breeding over several generations. The salmon also need better habitat, cleaner water, and improved routes through the river system. Removing the dams does not solve every problem they face.
