Acres of suitable spawning grounds await salmon in Upper Columbia River, study finds

chinook salmon

In a multi-stage effort to return migratory salmon to the Upper Columbia River so the fish may rekindle self-sustaining populations, scientists concluded that acres of suitable habitat await the salmon, should they be able to reach it.

Researchers at Pacific Northwest National Laboratory and the Confederated Tribes of the Colville Reservation collaborated to quantify spawning habitat as part of a larger effort led by the Upper Columbia United Tribes, who are exploring the feasibility of reintroducing salmon to the currently blocked stretch of the river.

By modeling the gravel and water fall and summer chinook salmon use when nesting, researchers assessed underwater habitat to better understand how spawning fish would fare in the river’s blocked stretch.

The assessment explored more than 47 miles of river running between Kettle Falls, Wash., and the Canadian border. The region could provide nesting space for 5,786 to 32,728 spawning adults, depending on how the fish space themselves.

“Our study was part of phase one, which assessed the overall feasibility of salmon reintroduction” said fisheries scientist Brian Bellgraph, a study coauthor. “And our findings showed there’s a decent amount of habitat up there.”

The phased plan is orchestrated through the Upper Columbia United Tribes — a tribal nonprofit representing the Coeur d’Alene Tribe, Confederated Tribes of the Colville Reservation, Kalispel Tribe of Indians, Kootenai Tribe of Idaho, and Spokane Tribe of Indians — and adopted into the Northwest Power and Conservation Council’s Fish and Wildlife Program.

Alongside researchers at the Confederated Tribes of the Colville Reservation, scientists from the U.S. Department of Energy’s PNNL detailed their findings in a study published in the journal Northwest Science. The study is one of many that inform a larger project led by Native American tribes to understand what challenges the fish face and how best to set them on a successful path.

To understand the habitat’s condition, the study’s authors combined existing data on riverbed conditions with new, similar data provided by the Confederated Tribes of the Colville Reservation to build a two-dimensional river model. The data capture the size of the gravel lining the river, flow levels, water velocity and slopes at different points along the riverbed.

Looking back

When construction of Grand Coulee Dam was finalized in 1942, it permanently blocked fish migration and prevented tribes from accessing long-held salmon fishing grounds, cutting off both a cherished food supply and a central figure to important cultural traditions.

“The salmon was at the very root of our existence,” said Tribal Councilmember Hemene James of the Coeur d’Alene Tribe. “We looked at salmon fishing not only as a gathering of the people, but also as the salmon giving its body to sustain the people, a deal that was made at the beginning of time between us and the salmon.” James works closely with fisheries managers and tribal members in reintroduction efforts, adding that such work stands to “fully connect our peoples’ spirits, minds, and hearts back to the land.”

Native American groups pass down some of their traditions through cultural and educational salmon releases. Fish from downstream hatcheries are carried into the river, often accompanied by singing, praying, storytelling, and sometimes fishing. In 2017, the Spokane Tribe released roughly 750 locally hatched, yearling chinook salmon into Tshimakain Creek, a tributary of the Spokane River. Of those, about 90 yearlings pinged fish-detecting devices downstream of Chief Joseph Dam. They had passed over three dams without fish passage and survived.

“We were really pleased by those numbers,” said Conor Giorgi, anadromous program manager of the Spokane Tribe of Indians. “Before that, we didn’t really have much information about juvenile behavior or survival through Lake Roosevelt or sections of the Spokane River. It was evidence that, yes, this is possible, and it also gave us a lot of hope.”

Another source of hope emerged in 2019 when an adult salmon from the 2017 release returned to the Columbia River Basin and migrated upstream, passing all hydroelectric facilities up to Chief Joseph Dam. Equipped with a tag, the female salmon pinged sensors as she swam upstream.

“Once I knew she had passed Bonneville Dam,” said Giorgi, “I started checking the database a couple of times per day, watching her slowly march upstream.” The fish was later named Nucucšnetkw, which translates to “she who retraces her steps,” and three of its siblings were detected in 2020. All three passed through a number of dams along the Columbia River, while one eventually reached a tribal fish processor in Oregon.

Challenges upstream

When traveling downstream, the only options for fish are swimming over the spillway to endure a steep drop or diving deep to swim through turbines. Neither Grand Coulee Dam nor the downstream Chief Joseph Dam offer juvenile fish bypass facilities. Although no anadromous salmon can swim upstream past the dams, redband trout are able to pass the dam when swimming downstream.

Discussion of fish passage is under way, as researchers consider transporting the fish upstream via truck or installing a Whooshh system, where fish pass over barriers by moving through a flexible, pressurized tube.

A changing climate, too, adds difficulty. Models project the main stem of the Columbia River could grow too warm for spawning salmon, said Bellgraph, while unlocking upper stretches of the river could provide cooler habitat. Warmer temperatures could diminish water levels, also, putting salmon closer together and adding stress to an already perilous journey. When salmon reach warm waters, they often stop swimming.

The Bonneville Power Administration funds and organizes habitat restoration projects downstream of Grand Coulee and Chief Joseph Dams. The work reconnects wetlands to the main channel, said policy analyst Laura Robinson of the Upper Columbia United Tribes, and curbs sedimentation that could otherwise compromise nesting sites.

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