Finally, Salmon Have the Run of the River

Salmon are swimming in parts of the Klamath River and its tributaries not accessible for a century just days after the completion of the largest dam removal project in US history. The removal of four aging dams along the California-Oregon border has opened up more than 400 miles of river as spawning grounds (see before and after photos here). All varieties of native fish—including steelhead trout, Pacific lampreys, coho salmon, and fall-run Chinook salmon—are expected to benefit, but especially spring-run Chinook, which have dwindled in number. Annual surveys, conducted in July, found more than 700 on average between 1990 and 2016, but just 115 this year, per the Los Angeles Times.

The fish, which return from the Pacific Ocean in the spring boasting large quantities of fat and venture upstream to spawn in late September and early October, were largely wiped out when the dams were erected and have lately returned to only two of the Klamath's lower tributaries. "Dam removal is probably the No. 1 most important thing that could happen to help spring Chinook," Karuna Greenberg, restoration director of the nonprofit Salmon River Restoration Council, tells the Times. "There's whole watersheds that are opened up to them now, and that could really help to buoy the whole population."

It won't happen overnight. "It's going to take multiple generations" of fish spanning a decade or more, Toz Soto, fisheries program manager for the Karuk Tribe, tells the Times. Spring-run Chinook need to travel more than 100 miles upriver to reach historical habitats, which will prove difficult. But scientists plan to track their progress, per the AP. They also plan to release hatchery-raised spring-run Chinook in Oregon. Populations of fall-run Chinook and coho salmon will also be supplemented in this way, per the Times. "I'm just really, really hoping that it's not too little, too late," says Greenberg. Efforts to restore the watershed, including by scattering millions of seeds of native plants, will continue for many years. (More salmon stories.)