Asian carp, which have come to dominate entire watersheds in the Mississippi River drainage, have been found in the Greenup Pool of the Ohio River, which extends from Greenup, Ky., upstream to Apple Grove, W.Va.

"We have positively identified bighead carp in the waters downstream from the Robert C. Byrd Locks and Dam," said Chris O'Bara, head of fisheries research for the West Virginia Division of Natural Resources. "We might not have a reproducing population of them, but we have them."

Bighead carp and their close relatives, silver carp, were brought to the United States from China in the 1970s by catfish farmers, who hoped the plankton-gobbling fish would reduce pollution in their ponds. Some of the imports escaped into the Mississippi watershed, where they eventually became established and began to reproduce.

In some Mississippi tributaries, Asian carp have become the dominant species, out-competing native fishes and affecting water quality. Silver carp routinely attain weights of 20 pounds or more, and bighead carp routinely reach 40 pounds. Under the right conditions, both species can grow to more than 100 pounds.

Silver carp are particularly bothersome because they tend to leap from the water when startled. Fishermen and recreational boaters have suffered concussions, broken bones and back injuries from collisions with airborne silvers.

U.S. Fish and Wildlife Service officials consider both Asian carp species to be invasive, and the feds are working with state game and fish agencies to try to control the invaders' spread.

O'Bara is part of a team of state officials trying to keep the upper Ohio River and its tributaries from getting overrun.

"We decided, as states within the Ohio watershed, to collaborate and work together on this," he said. "We have members on the team from Illinois, Indiana, Kentucky, Ohio, West Virginia and Pennsylvania. We're trying to figure out how to deal with the fishery and public-safety issues Asian carp create."

Sharp-eyed boaters and anglers might already have noticed the Asian carp posters that DNR workers have posted at several Ohio River boat ramps.

"We want people to know what Asian carp look like, so if they see something that looks like one, they can let us know," O'Bara said.

"We've even put a QR [code] on them that folks can hold their smartphones up to and get connected to a website where they can make their reports. They could also call us, or they could go to the DNR website, www.wvdnr.gov, and click on the Asian carp page. We'll have a form with a draw-down menu so they can tell us where they saw the carp."

Hook-and-line catches of Asian carp will be rare. Because the species feed on plankton, they're almost never hooked. Most catches occur when carp collide with lures or baited hooks and become snagged.

"If someone catches an Asian carp, or finds one dead, we'd like to know about it," O'Bara said. "Pictures are good; dead bodies are better."

Adults of both Asian species are fairly easy to identify because their eyes are located low on their heads. Young carp are much more difficult to identify - and because of that, O'Bara believes fishermen might unknowingly help hasten the species' spread.

"The young of both bighead and silver carp aren't easy to distinguish from gizzard shad and skipjack herring, which anglers often catch and use for bait. Because of that, we're asking anglers not to catch bait in one area and take it someplace else," he said.

"We're asking anglers to either use up all the bait they have or to discard it when they're finished fishing, but never to move it from one place to another."

Crews from West Virginia and Kentucky plan to survey the Greenup Pool extensively this year to try to determine how prevalent bighead carp have become, and whether silver carp are becoming established as well.

"If it's early in the invasion, maybe we can try to slow them down, if not stop them," O'Bara said. "If and when they come, our concern here in West Virginia is to try to at least manage them and perhaps try to control their numbers. We don't want to get into a situation where they make up a large part of the river's biomass."

Reach John McCoy at johnmc...@wvgazette.com or 304-348-1231.