BOISE, Idaho — Scientists in the Pacific Northwest are studying more than a dozen watersheds to develop templates on habitat restoration that could be used in similar streams to bolster struggling fish populations.
The federal government lists 28 populations of salmon and steelhead on the West Coast that need protections due to low numbers despite spending millions of dollars every year on restoration efforts.
The studies aim to make those efforts more successful. They focus on 17 watersheds in Washington, Oregon, Idaho, Northern California and British Columbia and examine the benefit of everything from dam removal to building artificial beaver dams in tributaries.
Creating templates for habitat restoration could save time and money by using strategies known to produce good results in similar habitats in the region, said George Pess, a research fisheries biologist for the National Oceanic and Atmospheric Administration.
“The overall goal is to learn enough to be smart about our restoration,” he said, noting that the studies will offer recommendations to private, tribal and government entities but won’t produce any legally binding regulations.
Most of the studies began in the 2000s. Pess said scientists are still discovering what works and the program will require years of monitoring. They are examining how fish use waterways and the challenges salmon and steelhead face throughout their lives in the different watersheds.
In previous restoration efforts, officials have taken out barriers, such as dams, to open up spawning habitat. The studies go further by trying to determine whether removing the barriers leads fish to change when they go to the ocean and return as adults, Pess said. That would mean restoration efforts need to ensure enough water flows through streams at critical times.
“It’s a terrific and much-needed project — getting a scientific basis for really teasing out the factors preventing the recovery of wild steelhead and salmon,” said Guido Rahr, president of the Wild Salmon Center, which works to protect rivers and wild salmon populations. “They’ve chosen watersheds with diverse and different geographies. It’s really going to be helpful.”
In northern Idaho’s Potlatch River, a tributary of the Clearwater River, monitoring started in 2005 and restoration work began in 2009. About 1,000 wild steelhead use the Potlatch.
Last year, state workers for the first time counted steelhead spawning beds above an area where a dam had been removed, said Brian Knoth, a fisheries biologist with the Idaho Department of Fish and Game.
Whether opening new habitat increases fish numbers or simply causes the existing population to spread out is a frequent question in the 17 study areas.
To get an answer, scientists place small tags in fish that give off a signal when passing through an electronic field. That allows young fish leaving and then returning as adults to be counted.
On central Oregon’s Bridge Creek, workers have built artificial beaver dams as part of the study, discovering that the real animals moved in to expand on human efforts.
“It’s OK if natural beavers join in on the fun,” said Stephen Bennett, a research associate of watershed sciences at Utah State University who is involved with that and other studies.
Of the 17 studies, nine are in Washington state. Perhaps the most ambitious involves the Elwha River and the 2012 removal of a 100-foot dam that increased habitat by 300 percent. It more than a doubled spawning beds for chinook salmon and steelhead above the dam site.
