New McNary Dam Passage Gives High Hopes for Pacific Lamprey

The Pacific lamprey, culturally significant to the Umatilla and other tribes, now has a shot at making it past the McNary Dam to spawn.

The U.S. Army Corps of Engineers is supplementing the fish ladder of the dam’s Oregon shore with an additional structure that offers water velocities more conducive to lamprey migration, the Union-Bulletin reported on March 8.

The structure would allow lampreys, which tend to move along the river bottom in water that flows more slowly than the upper levels preferred by spawning salmon and steelhead, to access the fish ladder and make it upstream, the Union-Bulletin said.

“We plan to conduct video monitoring to observe which velocity is preferred by migrating lampreys,” said Mark Smith, who managed the project for the Corps, to the newspaper. “We anticipate this prototype structure will help us learn quite a bit about what’s best for lamprey passage.”

Lampreys have been around for at least 450 million years, the oldest fish in the Columbia River system, according to the Columbia River Inter-Tribal Fish Commission (CRITFC). Though not in danger of extinction, they have declined from a former high of millions 30 years ago to just about 4,000 returning to the Snake, Clearwater and Salmon river drainages where they once teemed, said Aaron Jackson, lamprey project leader for the Confederated Tribes of the Umatilla Indian Reservation, to the Union-Bulletin.

Tribes in the Pacific Northwest use the lamprey for food and medicine, and the fish plays a key role in regulating inland aquatic systems. They spend their first four to seven years of life acting as filters in freshwater sand and silt, then move to the ocean where they become parasites, latching onto various saltwater prey, the Union-Bulletin said. After two to three years of that they return to their freshwater origins to spawn.

The Army Corps of Engineers work group that helped design and engineer the structure included tribal representatives, the newspaper said. Built by Marine Industrial Construction of Wilsonville, Oregon under a $336,542 contract, was completed in late February and is the first such installation in the mid-Columbia River, the Union-Bulletin said.

“We’re excited to see something like this put in the river,” Jackson said.

RELATED: Confederated Tribes of the Umatilla Reservation, Oregon