June 16, 2006

Conservation Department says efforts now must concentrate on assessing the size of the zebra mussel population and its impact on native species.

The discovery of zebra mussels in Lake of the Ozarks emphasizes the need for Missourians to increase efforts to protect our natural resources from invasive species. The Missouri Department of Conservation today confirmed that the Eurasian mussels have been found in Lake of the Ozarks. The zebra mussels were discovered this week after an alert citizen contacted the Conservation Department upon finding what he thought to be zebra mussels on items submerged below a dock at the lake.

While the introduction of zebra mussels in Lake of the Ozarks is unfortunate Conservation Department Invasive Species Coordinator Brian Canaday says it is not surprising.

"Each year there are tens of thousands of visitors to the lake," says Canaday. "It's likely the zebra mussels were unintentionally transported into Lake of the Ozarks by someone who did not detect the tiny mussels attached to his or her boat. Because adult zebra mussels can live for several days out of water there is a great risk for avid boaters to transfer the mussels from one body of water to another. That's why we encourage all water recreationists to inspect and thoroughly clean all fishing equipment, boats and other watercraft upon removing the items from a body of water."

Since their arrival in the U.S. in the mid-1980s zebra mussels have expanded their range west to the Mississippi and Missouri Rivers. The fingernail-sized black-and-white striped mollusks (similar to clams) are native to the Caspian Sea region. They were transported to North American waters in the bilge or ballast water of international ships and were first discovered in Lake St. Clair near Detroit in 1988. Since then, zebra mussels have spread rapidly throughout the Great Lakes and connected waterways of the Mississippi River, including the Arkansas, Illinois, Ohio and Tennessee rivers.

Zebra mussels were first reported in Missouri in 1991 in the Mississippi River. For eight years, they were not found west of the Mississippi in our state. In spring 1999, however, zebra mussels were reported in the Missouri River near Sioux City, Iowa. In August 1999, zebra mussels were found in the lower Meramec River, a Mississippi River tributary south of St. Louis.

The invading mussels feed on plankton, the microscopic plants and animals that form the basis of the aquatic food chain. This puts them in direct competition with native mussels and young fish, including bass, bluegill and other popular sportfishes. Zebra mussels can attach to power boats' drive units and clog water intakes, causing damage to engines.

Zebra mussels pose no health risks to humans but they can cause some problems. The sharp shells wash up on land, limiting access to beaches and encrusting boat docks and the hulls of boats left in the water.

Now that zebra mussels have been found in Lake of the Ozarks, the Conservation Department will work to limit damage from the species. The agency will establish a monitoring protocol to assess the size of the population and continue monitoring the lake to gauge its potential impact on native aquatic species.

"The best thing that can be done now is to educate lake users to take precautions against spreading zebra mussels to other waters," said Canaday.

Water recreationists can take the following actions to prevent the further spread of zebra mussels:
? Inspect boats and trailers thoroughly, and remove any trash, mussels or aquatic weeds before leaving any water body. Mussels and other items removed from the boat should be properly disposed of in a trash container.
? Drain water from the motor, live-well, bilge and transom wells, and any other water from the boat and equipment before leaving any water body.
? Dump leftover bait on land, away from the water.
? Rinse boats, trailers and equipment (including live-wells, bilge, and cooling systems) thoroughly with hard spray or HOT (104 degrees) water, like that found at a do-it-yourself carwash.
? Dry boats, motors, trailers and equipment thoroughly in the hot sun before using them again.
? Several Missouri STREAM TEAMS already are helping by monitoring lakes and streams for zebra mussels. If you would like to join the effort, call (800)781-1989 or visit the Stream Team web-site at www.mostreamteam.org.

Anyone who is concerned that their boats, other watercraft or fishing equipment may be infested with zebra mussels can contact the nearest Conservation Department office for assistance. For more information about zebra mussels contact Invasive Species Coordinator Brian Canaday at (573)522-4115 ext. 3371 or go online to www.missouriconservation.org, or www.protectyourwaters.net.