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State will try again to exterminate pike in High Sierra lake

The water was poisoned in '97 but the fish, a threat to native species, reappeared.

July 07, 2007|Eric Bailey | Times Staff Writer

SACRAMENTO — State wildlife officials are girding this summer for a chemical assault on the dreaded Northern Pike, a carnivorous fish that for more than a decade has bedeviled scenic Lake Davis in the High Sierra.

Ten years after the state poisoned the water in a highly controversial and ultimately unsuccessful bid to exterminate the pike, officials once again plan to treat Lake Davis with a menu of fish-killing chemicals. The state wants to keep the pike from escaping downriver to prey on salmon and other native fish.

The list of chemicals includes known carcinogens that in sufficient quantities can cause human health problems such as liver and kidney ailments or cancer. But state health officials contend that the chemicals, which will be released in minute concentrations, should dissipate within weeks to levels that won't pose a threat to people.

Such assurances have helped assuage concerns among many residents of Portola and other towns near Lake Davis. Even a few stalwart foes of the poisoning lament that it has been hard to generate much enthusiasm for a new battle against the state Department of Fish and Game.

"What they're proposing to do once again is absurd and insane, but there doesn't seem to be any fight left in the community," said Dan Wilson, a fifth-grade teacher from Portola. He believes the poison causes health problems in children, though there are not any studies to support him.

State officials dispute any connection to health problems and say their looming chemical assault is a necessary step to ensure that the invasive fish doesn't escape downriver. "We don't feel these chemicals are a safety hazard -- not in these amounts," said Steve Martarano, a Fish and Game spokesman.

The fear among wildlife authorities is that pike could reach the Sacramento-San Joaquin Delta, putting the bite on salmon runs and obliterating endangered delta smelt.

The pike first appeared in Lake Davis in 1994, probably dumped by an unwitting angler trying to introduce a new sport fish prized for its fight, state officials said. As the pike population took hold and grew, state Fish and Game officials in 1997 attempted the first chemical treatment using rotenone, a South American root extract.

By 1999, the pike had reappeared. Officials tried every method they could think of to kill the invaders -- catching them with nets, setting off explosives, shocking them with electricity. Nothing stopped the pike, which experts now believe may number more than 1 million in the lake.

The proposed chemical treatment, expected to be dumped into Lake Davis after the Labor Day weekend, is a newer version of the fish killer used in 1997.

A liquid that goes by the product name CFT Legumine, it includes rotenone but doesn't contain piperonyl butoxide, a suspected carcinogen and toxic substance that lingered in the lake for months after the first treatment.

CFT Legumine does have trace levels of hydrocarbons, which help disperse the rotenone through the water. Those chemicals are associated with human health problems such as cancer and kidney and liver ailments.

State Department of Health Services officials studied the chemical brew and, in a 13-page report, declared that if applied correctly it should produce no adverse health effects in the short or long term.

Randy Kelly, a Fish and Game environmental scientist, said the chemicals would be broken down within weeks by bacteria in the lake, would be absorbed by lake-bottom sediments or would evaporate into the atmosphere. "There are some individuals who don't want anything in their environment," he said. "We're trying to provide them with all the information we have, but we're never going to satisfy everyone."


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