Too many perch, bass, bluegill

GRANT COUNTY — The fish in Blue and Park lakes are scheduled to be eradicated this fall, the state Department of Fish and Wildlife announced Wednesday, as biologists continue efforts aimed at maintaining the historically popular trout fisheries.

The trout population continues dwindling in the lakes — anglers averaged less than one per rod on opening day this year — as perch, bass and bluegill populations swell and reduce food supplies for trout.

Blue and Park lakes, situated south of Banks Lake along High-way 17, are among Washington's top attractions for trout angling and arguably the most important opening day waters in Grant County since the 1950s, said Jeff Korth, a state fish and wildlife biologist stationed in Ephrata.

Biologists will use the organic pesticide Rotenone. The lakes are then stocked with trout.

Rotenone, which is extracted from ground-up roots of tropical plants, interferes with a fish's use of oxygen. The pesticide kills quickly and then rapidly dissipates from the environment.

Scientific review of rotenone by the U.S. Environmental Protection Agency supports its continued use. It's become a favorite of fish experts because they are able to eradicate entire populations of fish with minimum impact to non-target wildlife.

Park Lake is scheduled for rehabilitation on Nov. 6, taking about three or four days to complete, Korth said. Its larger neighbor, Blue Lake, is scheduled for rehabilitation on Oct. 23, and should take about a week.

All size and daily catch limits are suspended until the rehabilitation dates.

Rotenone was applied to Blue and Park lakes eight times since the 1950s, most recently in 1996.

Korth said 83 percent of public opinion collected this year by his agency favored rehabilitation.

"The vast majority tell us they want the two lakes managed as a trout fishery," Korth said Thursday. "If we're going to have the trout fishery everyone expects, (rehabilitation) is essential."

Those who oppose rehabilitation, Korth said, generally prefer catching the warm-water, spiny-rayed fish.

But managing Blue and Park lakes as warm-water fisheries, he said, creates less overall recreation, as evidenced by fewer numbers of anglers as trout fishing slows.

Only rotenone rehabilitation or stocking of catchable-sized fish can restore the trout fishery, Korth said.

If rehabilitation occurs every 10 years, the state would likely spend about $440,000. Those funds would pay for the rehabilitation itself, a one-time planting of catchable-sized trout, followed by nine years of planting fingerling trout, according to the agency's figures.

In comparison, for the same 10-year period, the agency estimated the state would spend about $1.5 million to regularly stock catchable-sized trout.

Without significant capital investment, current resources aren't available to provide catchable-sized trout on a regular basis without severely impacting hatchery production for many other fisheries, Korth said.

Trout quality improves considerably, he said, if smaller fish are planted and grow to a catchable size within the lakes.

"Rehabilitation provides the best quality fish, the cheapest," he said.

He expects anglers to haul in about three catchable-sized trout per rod on opening day next year. He anticipates "a really excellent fishery on opening day 2008" as fingerling trout planted in 2007 grow to size.