Invasive zebra mussels found in lake at Schell-Osage Conservation Area

Nevada, Mo. – Biologists have found zebra mussels in a lake at the Schell-Osage Conservation Area, which is in Vernon and St. Clair counties in west central Missouri. Zebra mussels are an invasive species from Eurasia that can cause ecological and property damage.

A Missouri Department of Conservation (MDC) crew conducting a fish study found small zebra mussels attached to a stick on Monday, May 6, said Tom Priesendorf, a MDC fisheries management biologist. The mussels were found in Barber Lake, a shallow oxbow lake in an old channel of the nearby Osage River. Barber Lake is in the flood plain for Truman Reservoir. Due to rains and high water, the reservoir was backed up into Barber Lake when the mussels were found.

Biologists do not know if the zebra mussels are in Truman Lake, or to what extent they are established in Barber Lake, said Tim Banek, MDC invasive species coordinator. But Melvern Lake in Kansas has established zebra mussels and that lake is on the Marais des Cygnes River, which feeds into the Osage River in Missouri. The larval stage of zebra mussels, called veligers, float downstream on water currents.

“We expect to get them in Truman Lake because it’s downstream from Melvern,” Banek said. “If they’ve floated down the Marais des Cygnes to Schell-Osage, within the next couple of years we’ll find them in Truman as well.”

Zebra mussels entered the United States in ship ballast water in in the Great Lakes. They caused billions of dollars of damage in the Great Lakes and Mississippi River systems. The mussels, which look like clams, reproduce in huge numbers. Adults attach to hard surfaces like pipes, docks, rocks, boat hulls and even native mussel shells. They form dense colonies. The sharp-edged shells can cut fishing line or the feet of swimmers.

“There’s nothing good about them,” Banek said. “They filter nutrients from the water that are used by our sport fish at certain early stages of life. They filter the same nutrients our large paddlefish and our forage fish like shad feed on all their lives.”

In recent years, the mussels have continued to spread to new waters. In Missouri, they were found in Lake of the Ozarks in 2006. Since then, they have also been found at Smithville Lake and Lake Lotawana in the Kansas City area, and in upper Bull Shoals Lake and Lake Taneycomo in southern Missouri. They are also in the Mississippi, Missouri, and lower Osage rivers.

How zebra mussels will affect fisheries in Missouri waters for the long term is still uncertain, Banek said.

“We haven’t had them here long enough to know what the effects will be,” he said.

Boaters can help stop the spread of zebra mussels. The mussels can move to new waters when adults are attached to docks or boat hulls, as they can survive for some time out of water. Also, water in boats, motors, bait buckets and live wells can transport the microscopic veligers.

Several large reservoirs highly valued by Missourians such as Stockton Lake, Pomme de Terre Lake and Table Rock Lake do not have zebra mussels. Also highly valued are the many small community lakes and rural ponds. Anglers and boaters taking proper precautions can help keep these waters from becoming infested with zebra mussels. Remember to clean, drain and dry boats and trailers before moving them between lakes and rivers.

• Clean – Remove all plants, animals and mud, and thoroughly wash everything, especially live wells, crevices and other hidden areas. If a boat doesn’t have a week to dry out before the next use, wash boat bilges, trailers, motor drive units and live wells with hot water at least 104 degrees. Most commercial car washers meet this standard.

• Drain – Eliminate all water before leaving the area, including live wells, bilge and engine cooling water.

• Dry – Allow boats and other equipment to dry in the sun at least five days before launching in other waters.

For more information:

Zebra mussels in Missouri, http://mdc.mo.gov/discover-nature/field-guide/zebra-mussel or

U.S. Geological Survey fact sheet, http://on.doi.gov/fIpdlK.