More than a year after 34,000 fish succumbed in the Klamath River, a long-delayed report released Tuesday by the U.S. Fish and Wildlife Service has concluded that low river flows, high water temperatures and crowded conditions helped produce one of the worst salmon die-offs on the West Coast.
The findings of the 115-page report, subjected in recent months to lengthy peer review and administrative scrutiny by the Bush administration, reiterated the conclusions reached by California biologists days after the October 2002 die-off that left the banks of the Klamath strewn with salmon carcasses.
Environmentalists, the fishing industry and Indian tribes said the report buttresses their long-held belief that the administration's pledge to boost irrigation supplies to Klamath Basin farmers threatens to further imperil salmon in the river.
"We've been scarred by that fish kill, and it's something our people are never going to forget," said Troy Fletcher of the Yurok tribe, whose members depend on Klamath salmon for food.
He and others fighting the Bush administration over Klamath River water allocations expressed hope that the government will increase river flows next year to give the fish a better chance for survival. They also advocate reducing agricultural demands on the river by purchasing some water rights in the Klamath Basin, a farm region straddling the border of Oregon and California.
"It should be pretty bonehead obvious that fish need water to survive," said Glen Spain of the Pacific Coast Federation of Fishermen's Assns. "If you keep cutting the water year after year, you'll eventually crash the system."
But a spokesman for the U.S. Bureau of Reclamation, which manages much of the West's vast water network, said no changes are expected. Both the U.S. Fish and Wildlife report and another study issued a month ago by a panel of scientists assembled by the National Research Bureau stop short of advising the agency to boost flows, said Jeff McCracken, a reclamation spokesman.
"Neither report specifically says a change in our releases down the river would have made a difference," McCracken said.
Environmentalists say that almost surely will mean another legal battle. And they say the Fish and Wildlife report will provide good ammunition.
Bush administration officials had promised the report within a few months of last year's environmental crisis. As the delays mounted, concern grew that the administration might blunt its findings for political reasons. Farmers are considered an important part of the president's powerful rural constituency.
But the study that emerged largely reiterates what biologists at the California Department of Fish and Game concluded within a few days of the fish kill.
The federal report said a large run of Chinook salmon -- the backbone of the commercial fishing industry -- was poised to head up the river a few weeks earlier than normal, but low river flows seemed to blunt their natural instinct to migrate to the spawning beds. Swarms of fish began congregating in the river's lower reaches, a few dozen miles from the Klamath's mouth south of Crescent City.
The crowded conditions, low river flows, warm water and seeming hesitation of fish to head upstream combined to provide "optimal conditions" for a proliferation of parasites and an outbreak of a disease commonly known as gill rot, the report found.
The Klamath historically has been the nation's third-most prolific river for salmon.
But the stocks have dwindled in recent decades because of effects of sediment from logging, chemicals and other runoff from cattle ranching and farming, and dams blocking migratory paths. Additionally, water has been diverted for agriculture, commercial fishing and other factors, leaving significantly lowered flows.