Alaska Fishing

As early as this fall, state sportfisheries biologists could drop a chemical into Cheney Lake in Anchorage to kill a pike population that has wiped out a popular rainbow trout and landlocked-salmon fishery.

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Fisheries managers still need permission from the state Department of Environmental Conservation to use rotenone, a chemical that kills fish by inhibiting their ability to use oxygen.

They hope to apply for a permit as early as this week. The permit process will include public input, said Kristine Dunker, a state fisheries biologist.

The lake is one of three in Alaska where the state hopes to use the chemical to target non-native pike populations. According to state fisheries biologists and a state environmental health official, the chemical dissipates quickly and poses little threat to mammals or humans in the amounts used.

Rotenone is a naturally occurring chemical that comes from a member of the bean family.

According to a manual on rotenone distributed by the American Fisheries Society, a professional society for fisheries scientists, a 160-pound person would have to drink 23,000 gallons of water treated at 0.25 milligrams of rotenone per liter of water (the highest allowable treatment rate for fish management) at one sitting to receive a lethal dose.

The chemical also typically breaks down within days and binds quickly to soil, limiting its spread and making it little threat to drinking water. It can, however, produce a smell akin to mothballs in high enough concentrations, according to the manual.

SPREADING WORRIES

Besides Cheney Lake, the state hopes to use rotenone in Arc Lake near Soldotna and in a series of ponds in Yakutat known as the "Village" or "Post Office" ponds.

At all three sites, biologists are worried about the pike spreading to nearby salmon streams. Arc Lake is only two miles from Soldotna Creek, which feeds into the Kenai River. Cheney Lake is just a hop and a skip from Chester Creek.

The Yakutat ponds are close to the Situk River, which supports the state's best steelhead run and is home to a thriving coho, or silver, salmon return.

The chance the pike could swim on their own to the streams is remote, but someone could illegally move them into the streams, where the voracious predators could devastate the salmon runs, said Bob Piorkowski, a state fisheries biologist based in Juneau.

At Arc and Cheney lakes, biologists also hope to restock trout and landlocked salmon once the pike are gone.

FORMER crowd-pleaser

Cheney Lake off Baxter Road in Muldoon used to be one of the most popular lake fisheries in the Anchorage Bowl, attracting a regular stream of anglers throughout the summer in canoes, float tubes and paddleboats.

State biologists started stocking it in 1982 and some years poured in more than 20,000 rainbow trout and landlocked salmon, said Dan Bosch, the state biologist responsible for managing sportfisheries in the Anchorage area.

Biologists stopped stocking in 2001 after pike were discovered, and now it gets only passing use by fishermen, he said.

Pike thrive in shallow waters, where they feed on insects, frogs and other fish. They are not native to Southcentral Alaska.

The department has tried to eradicate the pike in Cheney Lake by gillnetting them and by encouraging anglers to target them, but it hasn't been enough, Bosch said. The lake is in a former gravel pit so it has no native fish population, he said.

If the permit is approved, biologists would like to treat the lake in October just before ice-up, Dunker said. They would then come back in the spring with nets to make sure pike were eliminated.

The plan is the same at Arc Lake on the Kenai, said Robert Massengill, a state biologist heading up the effort there.

PUBLIC REACTION

According to Rosemary Lombardi, an environmental specialist in the Environmental Conservation Department's pesticide program, rotenone is an ingredient in some over-the-counter insecticides and is used on some crops.

But it requires a permit for commercial application. It has been used in many places in the Lower 48, including a widely publicized effort in 2007 in Lake Davis in California.

Peggy Robinson, who sits on the Northeast Community Council, which includes Cheney Lake, said she thinks residents would generally support bringing back the fishery.

Her own children used to fish often at Cheney Lake, she said. But she suspects many people would want to hear more about the use of rotenone before they would accept it.

Steve Sommerfeld, an area resident who also sits on the council, however, said he would oppose any use of the chemical. He has read concerns on the Internet about rotenone and is distrustful of using any chemical that kills an animal no matter the assurances about its safety.

"I'm of the opinion that the use of any kind of chemical or pesticide has side effects," he said.

Find S.J. Komarnitsky at www.adn.com/contacts/skomarnitsky or 352-6714.

PIKE KILLER: The American Fisheries Society manual on rotenone includes a description of the chemical and its effects.

www.fisheries.org/units/rotenone/Rotenone_Manual.pdf

EDITOR'S NOTE: A link to the state's pike management plan in yesterday's Alexander Lake story had some bad coding: Here is the correct link:

PIKE INVASION: To learn more about the spread of pike in Alaska and the state's current management plan, go to

www.sf.adfg.state.ak.us/region2/pike/pike_management_plan.pdf

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