Dam operators across the Columbia River Basin are not doing enough to protect endangered bull trout, according to allegations in a federal lawsuit filed this week.

Two Bureau of Reclamation facilities on the Yakima River are mentioned in the suit, which was filed in U.S. District Court by the Montana-based environmental group Alliance for the Wild Rockies.

But biologist Jeff Thomas, head of the Yakima Basin office for the U.S. Fish and Wildlife Service, said the facilities targeted by the lawsuit are far from the biggest threats to the declining species.

That’s because the lawsuit targets hydroelectric projects and the two identified in the Yakima Basin — Chandler and Roza — are actually located off river. Water is diverted to them from dams that have fish ladders.

Moreover, most of the remaining bull trout live high in the basin’s headwaters because they depend on clear, cold water habitat.

Reclamation’s five storage dams, which lack fish passage, are a much larger problem for bull trout because the fish are essentially trapped in shrinking populations, Thomas said.

The large fish, which can reach 30 pounds, can wander long distances, but they don’t migrate to the ocean and back like salmon.

“They’ll run into one at Roza (Dam) from time to time, but it’s kind of mysterious where they are coming from and where they are going,” Thomas said. “I think they can get past Roza the same as salmon.”

Population estimates based on the most recent counts of spawning beds in creeks put the number of bull trout in the Yakima Basin around 1,000; some of the dozen or so isolated populations have just a few fish remaining.

The lawsuit, which targets 26 hydropower dams in the Columbia Basin, seeks to have the dam operators consult with the U.S. Fish and Wildlife Service to ensure that the dam management doesn’t damage critical bull trout habitat. That’s required under the Endangered Species Act.

“As bull trout continue to decline, and since the law requires specific actions by federal agencies, we have no choice but to go to court to force these agencies to follow the law,” said Alliance director Michael Garrity in an email. “Fact is, you can’t bring endangered species back from the brink of extinction without a plan.”

A spokesman for the Bureau of Reclamation said the agency could not comment on ongoing litigation.

Thomas said such plans are in the works and he expected them to be done next year.

“It puts pressure on completing the process in a timely fashion; officially its been underway for 10 years,” said Alex Conley, director of the Yakima Basin Fish and Wildlife Recovery Board.

Bull trout were first listed as endangered in 1998.

Conley added that it would be interesting to see if the case brings more attention to bull trout management in the Columbia River, where most of the focus is on migratory salmon.

 This article has been updated to clarify that the Reclamation facilities named in this lawsuit are hydropower plants associated with diversion dams but not located directly at the dams.