SEATTLE — Scientists knew ocean-going 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 8 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.
After the two dams were built, all five native species of Pacific salmon and other sea-going 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.
Scientists knew fish would recolonize the river, a process that is likely to take decades, but “it’s always nice to confirm,” McHenry said.
“The message is game on. They’re active. They’re in the watershed. They have access now,” McHenry added. “Next year will be pretty exciting. 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?”
In recent months, biologists with the tribe and the National Oceanic and Atmospheric Administration have been walking the banks of the Little River — a tributary of the Elwha between the two dams — to track winter run steelhead returning to spawn.
This past spring, the biologists tagged about 40 mostly female adult winter steelhead and relocated them to the cooler, clearer waters of the Little River. Walking along the riverbank one rainy June morning, the biologists spotted several male steelhead that had no tags and which they hadn’t moved.
One male in particular was 35 inches, much bigger than any of the male fish they had tagged; it also lacked the fungus blotches that characterized the ones they had moved, McMillan said.
“We both looked at each other, and thought, ‘Wow. This is cool,’” said John McMillan, a fish biologist with NOAA’s Northwest Fisheries Service Center, who was with Ray Moses, project biologist with the Lower Elwha Klallam Tribe.
“Based on the size and lack of tag … we can only surmise that it made it up there on its own,” he said.
McMillan said it’s likely the male steelhead were drawn to the clearer waters or sought out their female mates, who excrete fluid when they spawn.
Another indication that fish are making their way past the former dam site: The biologists spotted a spawning redd in Indian Creek, another Elwha tributary, where they did not relocate any fish.
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.
The Elwha River is closed to all fishing year-round during a five-year moratorium to help the river following the removal of the two dams.
“It’s a lot of fun to see a fish make it past an area that has blocked migration for almost a hundred years,” McMillan said. “That’s the ultimate goal of the whole project. That it happened rapidly and that it was a steelhead was apropos.”