Sea lions that have faced death by lethal injection for making banquets of endangered fish in the Columbia River won a reprieve Tuesday when a federal appeals court told Oregon and Washington wildlife officials to cease killing them.

The 9th U.S. Circuit Court of Appeals said the federal government failed to explain why it lets state officials kill sea lions, while humans are allowed to take comparable or larger catches of the endangered salmon and steelhead.

Angry fishermen along the river have protested over the past decade as growing numbers of the sea lions clustered at the base of Bonneville Dam, where fish waiting to head upriver to spawn are easy pickings.

In 2008, the federal government gave Oregon and Washington state agencies the go-ahead to kill the hungriest of the sea lions, a decision challenged by the Humane Society of the United States.

In the past two years, 24 of the California sea lions have been killed. They are captured at the dam and taken to a facility where they are given a lethal injection by a veterinarian.

"The government's plan to kill sea lions for eating fish, while at the same time authorizing fishermen to take four times as many fish as sea lions, is irrational," society Vice President Jonathan Lovvorn said Tuesday in a statement.

The appeals court noted that — depending on how large the yearly runs prove to be — commercial, recreational and tribal fisheries are allowed under a separate federal assessment to catch 5.5 percent to 17 percent of the salmon and steelhead listed under the Endangered Species Act.

The National Marine Fisheries Service judged that such a catch would have minimal impact on the species' chances of survival, the judges said. But that finding is "in apparent conflict" with the agency's finding that a comparable or smaller take by the sea lions would have a "significant negative impact," they said.

Based on federal agency observations, sea lions' take has ranged from 0.4 percent to 4.2 percent, although the agencies believe that's a minimum, the court said.

The sea lions also are protected by federal law, but an exception allows them to be killed if they pose a significant threat to the fish.

The judges ordered the case to be sent back to the fisheries service, with an observation that its conclusions "raise questions as to whether the agency is fulfilling its mandates impartially or competently."

Spokesman Brian Gorman said the agency is disappointed with the decision but hadn't decided on its next step.