Feb. 28 (Bloomberg) -- The last time California tried to poison a lake in the Sierra Nevada to exterminate the northern pike, opposition was so intense that a local mayor chained himself to a buoy and a police SWAT team restrained angry crowds.

State officials are remembering that lesson now that the pike is back and they once again want to poison Lake Davis to eliminate the fish, which threatens to wipe out native species. They say an eight-year public relations campaign has won over residents worried about toxic residue tainting their water.

``They've involved the community this time,'' said former Plumas County Supervisor Fran Roudebush, who led opposition during the 1997 fish kill. ``Whether you agree with what they are going to do or not, at least they've engaged us this time.''

The state has tried netting the northern pike, stunning them with electricity and killing them with underwater explosions. It has removed 60,000 pike from the lake since 2000, according to the state Department of Fish and Game's Web site.

Officials said it could cost California as much as $700 million a year if northern pike, a fast-breeding, toothy predator, escape into rivers below Lake Davis. Adult pike, which can weigh more than 40 pounds (18 kilograms) will eat everything from trout and salmon to frogs, crayfish and ducklings, according to the Web site.

Water shipments from the rivers to California's agricultural Central Valley would have to be curtailed to prevent the torpedo-shaped pike from spreading statewide, officials said. That would cost as much as $535 million a year in lost farm output and labor, on top of recreational fishing losses.

`Devastating Impact'

``Pike getting out into California could have a devastating impact on our economy,'' said Ed Pert, the project manager at Fish and Game in charge of treating the lake. ``The pike is a wonderful critter, but not in California.''

The department suspects that anglers brought live pike to California to build a population of the fish, which is a prized catch in the Midwest. Last year, game wardens apprehended two fishermen transporting live pike.

Lake Davis is a reservoir about 150 miles (240 kilometers) northeast of Sacramento that was built in 1967 within the Plumas National Forest. Constructed with recreation in mind, it also supplies drinking water. The lake and surrounding forests are popular for boating, fishing, hiking and hunting.

In 1997, the state poured 33,000 gallons (125,000 liters) of the chemical rotenone into the lake, over the objections of protesters among the local population of about 2,500 people. Rotenone, a pesticide, suffocates fish.

Chained to a Buoy

Snipers and a SWAT team protected the Fish and Game workers from hundreds of opponents. Bill Powers, then mayor of nearby Portola, and three other protesters spent four hours chained to a buoy in the lake. They gave up only after hypothermia set in, and they were arrested on the shore.

At the time, Fish and Game promised that the chemical wouldn't escape the lake and would dissipate quickly. But an additive used with the chemical leaked downstream and lingered in the local water supply, according to the California Department of Health Services. The lake was closed to recreation for nine months.

Within two years, the pike were back. Some fish may have survived the poisoning, or people may have restocked the lake, officials said.

When the pike were again discovered in 1999, the newly appointed director of Fish and Game, Robert Hight, immediately traveled to Lake Davis and met with local officials, a step his predecessor hadn't taken.

Hight formed a task force of state and local officials to deal with the pike. He opened a Fish and Game field office in downtown Portola, 4 miles from the lake.

Going Native

``It was a bold move but an absolutely critical move,'' said the current Fish and Game director, Ryan Broddrick. ``We were committed to putting a face on the department. We were committed to having an exchange with the community, and you can't do that remotely from Sacramento.''

Under the new plan, the state agreed to hire an appraiser and a forensic accountant to calculate how property values and businesses may be affected. Owners would use the data to support claims with the state for compensation.

``It's been like night and day,'' said Powers, the former mayor. ``They've been very straight with us.''

In September, the state plans to use a form of rotenone that doesn't have petroleum distillates, cancer-causing chemicals used in the first treatment of the lake.

Nevertheless, some residents remain wary.

``Nothing they ever say will make me feel comfortable,'' said Rich Delano, a 30-year-old carpenter who lives less than a mile from the lake. ``What they are putting in there kills things. It's poison.''

To contact the reporter on this story: Michael B. Marois in Sacramento at mmarois@bloomberg.net.

Last Updated: February 28, 2007 03:01 EST