HAPPY CAMP, Calif. -- Centuries before federal nutritional guidelines told Americans how to eat healthfully, the Karuk Indians had figured it out.

They ate wild salmon at every meal -- about 1.2 pounds of fish per person per day. Isolated here in the Klamath River valley in the rugged mountains of northwest California, the Karuk stuck with their low-carb, low-cholesterol, salmon-centered diet longer than perhaps any Indians in the Pacific Northwest. It was not until the late 1960s and the 1970s, when dams and irrigation ruined one of the world's great salmon fisheries, that fish mostly disappeared from their diet.  

Salmon are now too scarce to catch and too pricey to buy. The tribe caught about 100 chinook salmon last fall, a record low. Eating mostly processed food, some of it federal food aid, many Karuks are obese, with unusually high rates of heart disease and diabetes.

"You name them, I got them all," said Harold Tripp, 54, a traditional fisherman for the tribe. "I got heart problems. I got the diabetes. I got high cholesterol. I need to lose weight."

On his first day as a fisherman for the tribe in 1966, Tripp remembers catching 86 salmon. Last fall, he caught one. "I mostly eat hamburger now," he said.

To reclaim their salmon -- and their health -- the Karuks are using the tribe's epidemic of obesity-related illness as a lever in a dam re-licensing pending before the Federal Energy Regulatory Commission. In what legal experts say is an unprecedented use of the regulatory process, the tribe is trying to shame a major utility company and the federal government into agreeing that at least three dams on the Klamath River should be knocked down.

The dams are quite literally killing Indians, according to a tribe-commissioned report that was written by Kari Marie Norgaard, a sociologist from the University of California at Davis. The report links the disappearance of salmon to increases in poverty, unemployment, suicide and social dissolution.

"We can't exist without our fish," said Leaf Hillman, vice chairman of the Karuk, whose 3,300 members make up the second-largest Indian tribe in California. "We can only hope that this will be one of those rare instances where a true look at the cost and benefits of those dams will be a compelling argument."

The tribe's demand for nutritional justice presents a prickly new problem to federal regulators at a time of major upheaval in the hydropower industry.

Federal licenses for private dams, valid for 30 to 50 years, are expiring in droves, especially in the Northwest, where hydropower accounts for about 80 percent of the electricity supply. In the next decade or so, licenses are due to expire at more than half of the country's non-federal dams -- 296 projects that provide electricity to 30 million homes in 37 states.

The Karuks "have raised something that is novel, and FERC commissioners will have to grapple with it," said Mary Morton, a legal adviser to Nora Mead Brownell, one of President Bush's four appointees to the commission that rules on license renewals for private dams.

Politically, it is hardly a propitious moment for Native Americans to demand that dams come tumbling down. Power rates have soared in California and across the Northwest in recent years. Bush has repeatedly spoken out against the breaching of federal dams on the nearby Snake River, saying it would be bad for the economy. His appointees as FERC commissioners are considered unlikely to force any utility to remove a dam, and his administration recently granted dam owners a special right -- denied Indian tribes, environmental groups and local governments -- to appeal Interior Department rulings about how dams should be operated.

Still, the aging dams on the Klamath River are, at best, marginal producers of power. They were built without fish ladders (unlike most major dams in the Northwest), and there is widespread scientific agreement that their removal would revive several salmon runs.

California, which could block a renewed federal license for the dams under provisions of the Clean Water Act, seems decidedly unenthusiastic about keeping the dams in the river. The state Energy Commission has said removing them "would not have significant impact" on the regional supply of electricity and that replacement power is readily available.

The State Water Resources Control Board, which regulates water quality and could veto a renewed license, blames warm, sluggish reservoirs behind the dams for "horrible" algae blooms in the river, said Russ Kanz, a staff scientist for the board.

In addition, the National Academy of Science and local officials in Humboldt County agree that dam removal is an option that should be examined to bring salmon back to the Klamath.

But PacifiCorp, the company that owns the dams, did not list dam removal as an option in its application last year for a new long-term license.

In the Clinton era, when tribes and environmental groups used the relicensing process to force utilities to pay hundreds of millions of dollars to retool or remove dams, PacifiCorp agreed to remove a hydro dam from the White Salmon River in Washington state -- at a cost of $20 million. The company, which is owned by Scottish Power, has 1.6 million electricity customers in six western states.

As part of its relicensing application for dams on the Klamath, PacifiCorp is trying to negotiate a separate settlement with the Karuks and other stakeholders along the river. Dam removal is now "on the table" in those talks, said Jon Coney, a company spokesman, adding that the tribe's health argument is part of the negotiations.

Coney, though, said that the tribe's health claims are difficult to substantiate in a scientific or legal way.

"How do you separate the health problems out from all the other societal things that have happened to the tribe?" Coney asked.

To make their case, the Karuk Tribe offers tribal health statistics and stories of its people who have grown ill in the years without salmon.

Diabetes and heart disease were rare among tribal members before World War II. Part of the reason was the super-abundance in their salmon-rich diet of omega-3 fatty acids, which research has linked with reduced risk of heart disease, stroke and diabetes.

"We do know that the nutritional values of subsistence fish are superior to processed foods and convenience foods," said William Lambert, an environmental epidemiologist at Oregon Health & Science University in Portland.

With subsistence fish all but gone from the Karuk diet, the percentage of tribal members with diabetes has jumped from near zero to about 12 percent, nearly twice the national average, according to the tribe. The estimated rate of heart disease among tribal members is 40 percent, about triple the national average.

A number of studies of Native Americans across the United States have shown that the loss of traditional foods is directly responsible for increasing rates of obesity-related illnesses.

Steve Burns, a physician for three years in the tribal clinic in Happy Camp, said that diabetes and other obesity-related illness are "a huge and growing problem."

"What is happening to the Karuk people is like something you would read about in a book on the destruction of a minority group in the old Soviet Union," he said.

The change in the tribe's diet in the past generation has been so great that many Karuk concede that it will be difficult -- even if the dams are knocked down and salmon runs are revived -- for them to return to their traditional healthful diet.

"Of course, we won't be able to eat salmon all the time like we did," said Ron Reed, a traditional fisherman and tribal representative to FERC hearings on the dams. But he said everyone in the tribe would eat vastly more than they do now and that children would once again be able to grow up with the staple food that has traditionally kept the bodies and spirits of the Karuk healthy.

Last year, because of the record-low catch, tribal elders did not have enough salmon for religious ceremonies. So they bought some.