Invasive mussels stopped before spreading
iMany years ago, tiny hitchhikers went unnoticed in a tank of live carp shipped from China to a New Jersey fish farm. The hitchhikers — larvae of Chinese pond mussels — had long baned Europe, but they'd not been documented in the United States until a discovery at the Hunterdon County farm in 2010.
Unseen, the larvae established themselves in the muddy bottoms of ponds at the fish farm, which supplied carp to Asian restaurants in New York City. In 2007, the retiring fish farm owners sold their farm to New Jersey Conservation Foundation for a nature preserve. Land stewards later discovered that the ponds contained bighead carp, an invasive species that could wreak havoc in natural systems if allowed to escape. But the discoveries didn't stop there. Biologists noticed something else in the mud: mature Chinese pond mussels, some as big as dinner plates.
"This was the first population discovered in North America, and as far as we know, the only one," said Tim Morris, stewardship director for New Jersey Conservation Foundation. "We knew we had to keep them from spreading."
Chinese pond mussels, he noted, "have taken over some rivers in Eastern Europe, where they outcompete native species."
With America as the top biodiversity hotspot in the world for freshwater mussels, they also threatened populations here. But thanks to work funded by the U.S. Fish and Wildlife Service this summer and fall, the Chinese pond mussel population in Hunterdon County has been eradicated, eliminating the danger of the species spreading to local waterways and, ultimately, the Delaware River.
"It's a significant success in invasive species management," said Eric Schrading, the U.S. Fish and Wildlife Service's New Jersey field office supervisor.
After the ponds were treated with an algaecide approved for killing invasive mussels, they were searched extensively and no live mussels were found, according to Melanie Mason, a land steward for New Jersey Conservation Foundation. "We feel pretty confident that they're gone, but we will follow up by doing environmental DNA testing of the water to make sure."
Project partners include the U.S. Department of Agriculture's Natural Resources Conservation Service, the New Jersey Division of Fish and Wildlife, the Friends of Hopewell Valley Open Space's New Jersey Invasive Species Strike Team, Earth Science Labs, Solitude Lake Management and the New Jersey Department of Environmental Protection.
Sandy Perry is staff writer at the accredited New Jersey Conservation Foundation.