Federal water diversions from the Klamath River were the primary cause of a massive fish kill in the Klamath River last September, concludes a new report from the California Department of Fish and Game (DFG).

More than 33,000 adult salmon, including federally protected coho, died before they could spawn because of federal water diversions to upstream farmers. The lack of water in the river caused river temperatures to rise and dissolved oxygen levels to drop, creating lethal conditions for salmon, the report finds.

The returning fish crowded together in a few spots where cooler tributaries brought colder water into the river. Infectious bacteria and parasites swept through the schooled fish, killing almost all and weakening the rest.

"DFG concludes that low flows and other flow related factors (e.g. fish passage and fish density) caused the 2002 fish kill on the lower Klamath River," the report states. "Furthermore, of the conditions that can cause or exacerbate a fish kill, flow is the only factor that can be controlled to any degree."

"This report confirms that the Bush administration killed more than 33,000 salmon," said Kristen Boyles, an Earthjustice attorney. "And the truth is the tragedy on the lower Klamath River could be repeated unless the plan for federal irrigation is overhauled."

In March 2001, Interior Secretary Gale Norton attended a ceremonial release of water to farmers in the Klamath River basin. The water had been withheld the previous year due to concerns over endangered fish, but under a new 10 year management plan, the water would continue to be provided to the farmers despite risks to fish.

The California DFG warns that more damaging fish kills are likely under the current federal plan saying, "There is a distinct potential for future fish kills considering that pathogens are always present, temperatures are normally at levels that can cause disease and, under the 2002 BO [biological opinion] flow prescription, a moderate sized run of salmon and steelhead can generate high enough fish densities in the lower Klamath River to result in a major fish kill.

Earthjustice is challenging the 10 year federal irrigation plan blamed for the fish kill on behalf of commercial fishers, conservation groups and Representative Mike Thompson, a California Democrat who represents northern California coastal communities that were hit economically by the fish kill.

The plaintiffs charge that the irrigation plan ignores the best available science, and was approved in a biological opinion issued by the National Marine Fisheries Service (NMFS) after NMFS overruled one of its own scientists who warned that the irrigation guidelines would damage the river ecosystem and the salmon fishery.

"The current federal water plan ignores science, and instead relies on guess work, wishful thinking, and voluntary measures," said Glen Spain of the Pacific Coast Federation of Fishermen's Associations Northwest Office in Oregon. "This is the water plan that killed the fish. Why should farmers have all the water they need while coastal fishing dependent communities and fishing families wind up with dead fish and dry rivers?"