From the depths of the onboard holding tank, the dip net yielded the bounty of the lake. Strong, bronze tails thrashed the water into a froth as these eight-pounders fought captivity. Hoisted from the water, the sloped faces and round mouths were more clown-like than ugly on these carp. Earlier in the day, researchers had been tracking other carp; fitted with radio transmitters to shed light on their lives and times in Clear Lake.

Sure. But....why carp?

"Yeah. We get that question quite a lot," grinned researcher Chris Penne. Penne and fellow grad student Nick Ahrens are halfway through a two year study, tracking the ugly, unwanted rough fish; part of a study between the Iowa State University based Cooperative Fish and Wildlife Research unit and the Department of Natural Resources. "We explain to people that the carp population is too high in the lake," explains Ahrens. "As carp feed, they stir up sediment and uproot aquatic vegetation. That has a negative impact on water quality and on game fish."

Many outdoor enthusiasts are familiar with radio telemetry. Everything from deer and bobcats to turtles and peregrine falcons have been tracked at one time or another in Iowa Just a few weeks ago, I rode with a crew following flathead catfish; concerned about potentially dwindling numbers and habitat in interior streams. Carp, though, seem pretty well entrenched in Iowa water. Having been introduced by 19th Century sportsmen, longing for European sport fishing, they eventually overran many lakes and rivers-the carp, not the sportsmen. That's where this 'Carp Crew' takes the stage; concerned not with stabilizing or improving conditions for the target species, but reducing their numbers.

Commercial fishing nets about 100,000 pounds of rough fish each year from Clear Lake; half of it carp. Sounds like a lot, but it is a yield of only 30 pounds an acre on this 3,600-acre lake. "We estimate 150 to 300 pounds an acre is possible," suggests DNR fisheries biologist Jim Wahl. "We would like to see carp harvest in the 50 percent range to make a good dent in the population."

That's a tall order for commercial fishing operations. This study, though, will reduce the guesswork. "We are seeing trends (and) getting good information," advises Penne. "In the winter, carp tend to school up in large numbers. We actually found 23 of our 30 (radio-tagged) adults within 100 meters of each other! During spring, they tend to run in shallow in the west end of their lake, probably due to spawning. Post-spawn, they move out to deeper waters."

Should the research hold, it will be valuable; here and on other lakes where rough fish have become major problems. Commercial fisherman could work more efficiently; targeting certain areas at certain times of the year to increase their haul.

Aiming the 14-foot wide mast to hone in on various frequencies, Penne and Ahren located carp '151.' The eight-pounder was 200 yards out from shore, in five feet of water. A week prior, he was grubbing through cattail beds on the west edge of the lake. Meanwhile, '48.301' (each ID comes from a fish's transmitter frequency) was skittish. "He seems to move every time we come close in the boat," recalls Ahrens. "He doesn't like to sit still." The researchers also surgically implanted transmitters in eight to 10-inch juvenile carp this spring. That gave them important data on smaller fish, before their 90-day batteries expired.

"We track lots of variables; not just calendar movements," notes Penne. "What depths they hold in, at certain times of the year; even where they go after precipitation or a temperature change." He points to Ventura Marsh, separated from the west end of Clear Lake by a low causeway and a human-built 'grade' which keeps fish from filling its muddy shallows. Rough fish here were removed several years ago. "The water quality increased when we removed the rough fish in Ventura Marsh," notes Penne. "By increasing removal in a lake, we think we would see a dramatic improvement in water quality...and more habitat for the game fish that anglers pursue."

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