Invasive zebra mussels eradicated in Virginia quarry

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RICHMOND, Virginia (AP) -- An infestation of zebra mussels in a Virginia quarry has been eradicated, marking what biologists and environmental experts believe is the first successful extermination of the notoriously invasive species in open waters.

The small black-and-white striped mussels, native to eastern Europe, are voracious eaters, gobbling up large amounts of plankton -- the same food many native freshwater fish need to survive. They also pose a threat to utility companies by clogging industrial pipes.

"I'm not aware of any other successful eradication," said Hugh MacIsaac, a zebra mussel expert at the Great Lakes Institute for Environmental Research in Canada. "That's quite impressive."

The zebra mussels were discovered in the United States in 1988 in the Great Lakes, after apparently being carried in a trans-Atlantic ship's ballast water. They have been found in 398 lakes nationwide, as far west as Kansas and as far south as Louisiana, the U.S. Geological Survey said.

They were first found in Virginia in a Prince William County quarry in August 2002.

"The economic and environmental damage that they can cause is tremendous," said Ray Fernald of the Virginia Department of Game and Inland Fisheries.

To eradicate the creatures, Aquatic Sciences L.P., of Orchard Park, New York, injected the quarry with thousands of gallons of potassium chloride solution over a three-week period beginning in late January. The solution does not pose a threat to the environment or humans, Fernald said.

The eradication process cost about $365,000, Fernald said. Water quality at the quarry and in nearby landowners' wells will be monitored for the next two years, he said.

While the technique could be replicated in smaller bodies of water, the approach would likely fail in a region as large as the Great Lakes, said Phil Moy, an invasive species expert at the University of Wisconsin Sea Grant Institute.

"The cost would just be prohibitive," he said.

Making eradication more difficult is the zebra mussels' ability to reproduce very quickly, said Thomas Horvath, a professor at the State University of New York in Oneonta who has been studying zebra mussels for about 15 years.

Researchers at Rensselaer Polytechnic Institute did have some success in 1999.

They began manually pulling the mussels from Lake George in New York. Since then, the population has declined dramatically, but has not been completely eradicated, said Sandra Nierzwicki-Bauer, a Rensselaer professor who directs the removal efforts.

"You're not going to necessarily get every single last one," she said. "But our goal was initially to go in and to remove the bulk of them. And we did that."

Amy Benson, a fisheries biologist with the U.S. Geological Survey, cautioned against celebrating too soon because the zebra mussels could be back next year. "Mother nature has a way of surviving," she said.