Salmon surprise scientists with speed of post-dam returns
PORT ANGELES – Scientists knew oceangoing fish would eventually return to the Elwha River on Washington state’s Olympic Peninsula, once two massive concrete dams were torn down. They just didn’t think it would happen so soon.
Biologists tracking fish in a tributary of the Elwha last month spotted wild steelhead that likely made it on their own past the site where the Elwha Dam stood for nearly a century – before it was dismantled in March as part of the nation’s largest dam-removal project.
“We’re wildly excited,” said Mike McHenry, fish habitat manager for the Lower Elwha Klallam Tribe. “It just confirms what we have known all along – that these fish are quite capable of recolonizing the Elwha once we get the dams out of the way.”
The tribe is a partner with the National Park Service in an ambitious $325 million federal project to restore the Elwha River, about 80 miles west of Seattle, and its legendary fish runs.
The 108-foot-tall Elwha Dam came down in the spring, and construction crews this month are blasting away pieces of the 210-foot Glines Canyon Dam about eight miles upstream. By summer 2013, the glacier-fed Elwha River is expected to flow freely as it courses from the Olympic Mountains to the Strait of Juan de Fuca.
Before the two dams were built, all five native species of Pacific salmon and other seagoing fish such as steelhead were confined to the lower five miles of this river. Once the two dams are removed, salmon and other fish that mature in the ocean and return to rivers to spawn will once again have access to more than 70 miles of spawning and rearing habitat, much of it within the protected boundaries of Olympic National Park.
“Next year will be pretty exciting,” McHenry said. “They’ll have the opportunity to ascend up. And all of a sudden they’ll be in a big national park. Where are they going to go and what are they going to do?”
Historically, steelhead traveled extensively along the 45-mile Elwha River and many tributaries. Before the dams were built in the early 1900s, an estimated 392,000 fish returned to the Elwha each year. Those numbers have declined to about 3,000, with an estimated 200 to 500 wild steelhead.