by K.C. Mehaffey
Mar 18, 2025

This month, salmon managers are releasing roughly 48,000 spring Chinook smolts from the Tucannon River—a tributary of the Snake River—in the far-flung Kalama River, more than 300 road-miles away.

The release marks the first year of a 14-year effort dubbed the Safety-Net Offsite Strategy to help preserve the genetic diversity of this dwindling population of Snake River salmon.

Despite their best efforts, salmon managers say they’re losing the battle to restore spring Chinook in the tributary, which flows into the Snake River between Little Goose and Lower Monumental dams.

And it’s not the only Snake River stock in trouble.

“I think that the Tucannon is the canary in the coal mine,” Dave Johnson, manager of the Nez Perce Tribe Department of Fisheries Resource Management, told a committee of the Northwest Power and Conservation Council March 10.

Johnson was joined by Chris Donley, Region 1 fish program manager for the Washington Department of Fish and Wildlife, and Jerimiah Bonifer, fisheries program manager for the Confederated Tribes of the Umatilla Indian Reservation.

The trio came to the Council’s Fish and Wildlife Committee seeking its support for the offsite program, which Donley described as “a fairly extreme action.”

The plan includes moving a portion of Tucannon River smolts from the Tucannon Fish Hatchery to the Kalama Falls Fish Hatchery each year for about six months before releasing them in the spring. Some of the smolts would also be moved to the nearby Lyons Ferry Fish Hatchery to be released in the Snake River.

Donley said the release of about 50,000 smolts into the Kalama River would result in roughly 250 adult fish coming back to the Kalama hatchery. Those fish would be trucked to the Lyons Ferry hatchery to be spawned. Chinook not needed for broodstock would be released into the Tucannon River to spawn.

Donley said efforts to restore the Tucannon River stock started with a supplemental hatchery program in 1985, using natural-origin fish from the basin. The stock did well until flood damage in 1996 and 1997 took out most of its spawning habitat, and production has been limited since.

Using scientific studies and adaptive management, fish managers have responded to every challenge, he said, adding, “We’re hanging onto these fish, but it’s not working.”

Donley noted, “One of the things that is puzzling to us as fish managers is there’s been a lot of work done here. Freshwater habitat looks pretty good in a lot of places.”

The Tucannon River flows out of the wilderness, and most of the spawning habitat is on public land. Habitat projects totaling between $25 million and $30 million have also been completed in the Tucannon River over the last 20 years.

Donley said it should be highly productive habitat, yet it’s not.

He said populations of spring Chinook upstream of Lower Granite Dam have survival rates that are double or triple the survival rate of Tucannon River spring Chinook, even though they are farther from the Pacific Ocean and have more dams to pass.

Scientists have identified some of the main problems.

One is that the Tucannon River is often warmer than the Snake River when adults are returning, causing a thermal barrier that prevents some Chinook from entering the Tucannon River. It also causes between 10 and 20 percent of the population to “overshoot,” or swim past the Tucannon River and continue upstream.

Predators pose another major problem for Tucannon spring Chinook.

Donley said birds and fish that eat salmon smolts have both increased in the Snake River basin. Last year, WDFW started analyzing the diet of walleye, a nonnative fish that is a popular sports fishing species.

The analysis found that walleye eat different things depending on the season. But at the peak of juvenile salmon migration, walleye bellies are filled with 100 percent salmonids, he said.

Tucannon spring Chinook are affected more because they are among the first species to begin the downstream migration to the ocean each spring. “They’re the only game in town for predators, and so they get picked off readily,” Donley said.

He said almost half of the smolts released from the Tucannon hatchery never make it to the Snake River. By the time the same batch of released smolts get to Lower Monumental Dam—the first dam they reach in their migration—more than 60 percent are gone. “That’s basically only 62 miles away from the release point,” he said.

Johnson said that Tucannon River spring Chinook have reached a quasi-extinction threshold, defined by 50 or fewer spawners on the spawning grounds for four consecutive years.

“We need to speed passage down to the ocean. We need to remove the injury and stress caused by physical structures—the dams themselves. We need to alleviate the artificial temperatures that are in the reservoirs, and we need to reduce the predation” that is unnaturally high because of the reservoirs, he told the Council.

Johnson urged the Council to consider funding safety-net programs in the Snake River as part of its Fish and Wildlife Program to help prevent the extinction of specific stocks, like the Tucannon River spring Chinook.

“The Tucannon [stock] is something that we all need to be concerned about. I hope that you as the power council take that as your real challenge going forth in the next 20 years,” he said.

News Data: Salmon Managers Begin Safety-Net Strategy for Tucannon Spring Chinook