Richmond, VA - The Virginia Department of Game and Inland Fisheries confirmed today that exotic zebra mussels (Dreissena polymorpha) have been found in an inactive quarry in Prince William County in northern Virginia. While it is not known how the mussels were transported to the quarry, the area is a popular underwater diving spot. It is possible that animals were carried in unintentionally via diving gear previously used in infested waters elsewhere in the United States. The Department is currently surveying other likely sites and examining its options for eradication of the mussels.
The zebra mussel is one of the most significant non-native species ever to be introduced into the country's freshwater ecosystems. The species can tolerate a wide range of conditions and is extremely adaptable. Department biologists are especially concerned about the potential for zebra mussels to devastate populations of rare and declining freshwater mussels in southwest Virginia. Zebra mussels can attach themselves to the native mussel shells, making it impossible for them to open or close, burrow in the stream bottom, or feed. As a result, in 1992, the Board of Game and Inland Fisheries added the zebra mussel to its list of predatory and undesirable animals that are prohibited in the state without a special permit. State laws and regulations also prohibit the release of any native, naturalized or exotic animal into the wild unless specifically permitted and/or authorized to do so.
Extremely efficient filter feeders, zebra mussels increase water clarity or transparency by removing microscopic organisms from the water. However, this increased clarity is directly related to a decrease in the types and availability of these food sources to the native fish and freshwater invertebrates dependent upon them. There are very few natural predators of this species in Virginia, and biologists expect that zebra mussels would spread rapidly through parts of the state unless otherwise eliminated.
Zebra mussels can also have a serious economic impact on facilities that depend on water intake by clogging or blocking pipes, valves, drains, and other workings. In fact, these animals will attach to almost any hard surface in the waters in which they occur, quickly spreading and covering that surface. The Department is asking public utilities and other major water users to check their intakes for any signs of zebra mussels.
To minimize the possibility of the further spread of zebra mussels in Virginia, the Department is asking divers and boaters to take extra precautions with their equipment. All dive equipment should be thoroughly checked and cleaned, especially the buoyancy control device and other items that retain water, and rinsed with hot water (greater than 140 degrees Fahrenheit). After a final rinse with clean fresh water, divers should allow all gear and equipment to dry completely before diving again. Hunters and anglers should follow similar procedures with waders, bait buckets, and any other equipment used in the water. Boaters should inspect and scrub boat hulls, anchors, and trailers, then hose equipment with hot and/or high-pressure water, keeping in mind appropriate water conservation requirements. Bilges, live wells, and any other compartments that could hold water should be drained at the site of origin, and, if possible, flushed with disinfectant or hot water. All boat equipment should be allowed to dry thoroughly before being used again.
First sighted in the United States in 1988, zebra mussels have spread quickly throughout the Great Lakes region and the Mississippi River drainage, as well as other waterways east of the Rocky Mountains. In 1993, zebra mussels were found attached to the hull of a motorboat transported to Smith Mountain Lake from the Great Lakes region. Appropriate actions were taken to clean the hull before the boat was launched, and the mussels were not introduced into the lake. For more information about zebra mussels and actions to reduce their spread, visit the Virginia Department of Game and Inland Fisheries Web site at www.dgif.state.va.us.
