Oregon and Washington officials have urged the federal government to delay for six months a final decision on whether to apply the Endangered Species Act to protect Columbia River coho salmon, an action that could bring further limits on development, timber cutting and other activities across a vast area from the coast to the Hood River basin.

The National Marine Fisheries Service proposed "threatened" status for the fish a year ago and is to make a final decision in June. Federal biologists said spawning by wild coho has largely disappeared everywhere but the Clackamas and Sandy rivers, and that populations elsewhere are dominated by hatchery fish. During the past 20 years, many surveys have counted no wild-spawned coho returning to lower Columbia River spawning grounds. Assessments in 1995 and 2001 concluded that the lower river stocks were nearly extinct.

In a letter sent April 19, Oregon and Washington officials assert that information gathered since last year shows that Columbia River coho are in better shape than federal biologists determined. Washington officials said their updated estimates show that the Cowlitz, Tilton and Lewis rivers are producing more than 400,000 coho salmon smolts a year, while federal biologists assumed there was no appreciable wild coho spawning success in Washington.

The state officials also argued that a six-month delay would provide time for the federal government to take into account the states' completed plans for protecting and restoring habitat, reforming hatchery practices, and regulating fishing to protect coho salmon. The letter was signed by Oregon Department of Fish and Wildlife Director Lindsay Ball, and Washington Department of Fish and Wildlife Director Jeffrey Koenings.

Bill Bakke, director of the Portland-based Native Fish Society, was the first to obtain and publicize the letter seeking the six-month delay. In an interview Monday, Bakke said state officials have exaggerated the health of lower river coho, in part by failing to distinguish between the offspring of hatchery fish and wild-spawned fish.

Steve Williams, a deputy administrator with the Oregon Department of Fish and Wildlife, said his agency is not advocating for or against a federal listing for the fish.

"What we're asking for here is the ability to bring together all of the information we now have available," Williams said, so that federal officials "will be able to make a more informed listing decision."

The National Marine Fisheries Service has not yet responded to the states' request. The Endangered Species Act generally requires the agency to render a final decision within a year of proposing a listing. Spokesman Brian Gorman said the law allows the agency to take an additional six months only if there is "substantial disagreement" regarding the sufficiency or accuracy of available data on the species in question.

"It has to be scientific uncertainty and not that someone is working really hard on a conservation plan," Gorman said.

Joe Rojas-Burke: 503-412-7073, joerojas@news.oregonian.com