Remember these Asian fish species: silver carp and bighead carp.

You will likely hear their names many times as Kentucky and neighboring states try to prevent the two invasive species from destroying sport and commercial fisheries, and endangering recreational boaters and water skiers.

If you are boating or skiing on the Ohio or Mississippi Rivers, in their backwater lakes or in many of their tributaries, you may see silver carp jumping several feet out of the water, or even into your boat.

Some fishermen in Western Kentucky, Missouri and Illinois have resorted to using garbage can lids, lawn chairs and other homemade shields to ward off the torpedo-shaped fish while their boats are moving.

The silver carp, which can weigh 60 pounds, can leap high into the air and strike boaters. Its relative the bighead carp is even larger.

"One fisherman was running up behind an island over here at 15 (to) 20 miles an hour, and about a 40-pounder jumped out and hit him right in the chest," said commercial fisherman Ronny Hopkins of Compliance Fish and Caviar in Livingston County, Ky. "He was down for two weeks. If he hadn't been sitting in a tractor seat with a solid back, it would have knocked him out of the boat."

Hopkins said he has had as many as 15 to 20 silver carp jump into his boat while running commercial nets, and various reliable accounts suggest that the silver carp, the most likely to jump, can rise 8 to 10 feet out of the water.

"They react to a boat and just go wild," said Benjy Kinman, the Kentucky Department of Fish & Wildlife director of fisheries. "If somebody bangs something or stomps on the floor of an aluminum boat — if they're up in a little creek mouth or something — they'll all jump out of the water like popcorn."

THE ASIAN CARP, which feed primarily on plankton, were brought to this country in 1972 by a fish farmer in Arkansas to help deplete an overgrowth of aquatic plant life. Several years later, they got into the Mississippi River basin and began showing up in Western Kentucky waters in high numbers about two years ago.

Inconclusive studies suggest that sport-fish numbers in some backwater lake areas of Western Kentucky may have declined significantly where silver and bighead populations are dominant.

"We're very concerned," Kinman said. "If they cohabitated in the same water body for a full year, are these things going to eat enough plankton to destroy the bottom end of the food chain so that there's not enough food for the sport fish?"

Further, young Asian carp are nearly indistinguishable from the shad and skipjacks that are widely used as bait fish, and Kinman worries that fishermen may spread the carp by carelessly emptying their bait buckets into uninfested lakes and streams. The Asian carp are already present in the Ohio River as far east as the Salt and Kentucky Rivers.

Scientists have not yet found a way to control the fish. They may grow to more than 4 feet; silver carp weigh up to 60 pounds and bigheads more than 100. Both species somewhat resemble Pacific salmon, except that the eye is very low on the head. Although a few have been taken with hook and line, such catches are rare. Hopkins said the meat of the bighead, unlike the silver carp, is quite tasty and can be marketed, but must be shipped rapidly and in great volume to be profitable.

DUANE CHAPMAN of Columbia, Mo., a U.S. Geological Survey fisheries biologist, has been conducting a study of Asian carp in the Missouri River, where they have been labeled "crazy fish" by locals. Chapman recently warned that water skiers would be risking their lives by skiing in silver carp-infested waters.

"It's a serious problem," Chapman said. "I have carp-guards on my boat — made of heavy netting that I can hide behind when I'm driving, and a board on the side to keep the fish from striking the throttle mechanism....

"I was hit in the head by one in the 15-pound range when I was standing up." Chapman, who is 6 feet, 6 inches tall, said the fish "got me right above the teeth. It didn't knock me down, but my neck was sore for about two weeks. It only takes one of these fish to take you out, and it could kill you."