By the Missouri Department of Conservation

Zebra mussels are now in Prairie Lee, Lake Jacomo and Blue Springs Lake. The prolific invasive species can harm boats, docks, and the aquatic ecology that supports sport fish. Boaters and anglers are asked to take steps to prevent them from spreading to other lakes.

Adult zebra mussels were first found in Prairie Lee Lake. On July 18 and 19, MDC biologists checked the lakes downstream in the watershed and found juvenile and sub-juvenile zebra mussels in Lake Jacomo and Blue Springs Lake. Zebra mussel densities in all the lakes are low at this point and visitors may not notice them being present, said Jake Allman, MDC fisheries biologist. Recreation at the lakes is not affected at this time.

Many other community lakes in the Kansas City metro area and reservoirs throughout the state do not yet have zebra mussels. Boaters and anglers can help prevent their spread to new waters.

Boaters who leave their boats on a lake with the mussels for more than a couple days should run the boat frequently. Small juvenile mussels are quite soft and are scoured off the hull at high speeds. On boats which remain in the water, zebra mussels can attach to drive units, cover or enter water intakes, and clog, overheat and destroy the engine. If possible, leave outboards or outdrives in the up position. Periodically inspect hulls and drive units, and scrape free of mussels. Pump hot water through your engine's intake regularly to prevent mussel growth inside the cooling system.

Zebra mussels can alter a lake’s ecosystem and harm fisheries. The mussels are filter feeders and will filter large quantities of water, which removes the microscopic plants and animals that most young fish need as their first foods. They can also smother native mussel beds and even attach to crayfish in large numbers.

Female zebra mussels can produce as many as one million eggs per year. These develop into microscopic free-swimming larvae called veligers that can float in current into new waters, such as downstream lakes. Veligers quickly begin to form shells. At about three weeks, the sand-grain-sized larvae start to settle. By using adhesive filaments called byssal threads, they attach to any firm surface. Zebra mussels clump together as they grow and cover rock, metal, rubber, wood, docks, boat hulls, native mussels, crayfish, and even aquatic plants.

To prevent the spread of zebra mussels to other lakes, and to keep your own equipment from being fouled, please observe the following clean boating suggestions when transporting your boat from waterway to waterway.

Inspect: Thoroughly inspect your boat's hull, drive unit, trim plates, trolling plates, prop guards, transducers, centerboards, rollers, axles, anchor, anchor rope and trailer. Scrape off and trash any suspected mussels, however small. Remove all water weeds hanging from the boat or trailer before leaving any water body. 

Drain: Drain water from the motor, livewell, bilge and transom wells and any other water from your boat and equipment while on land before leaving any water body. 

Dump: Dump leftover bait on land, away from water, before leaving any water body. Leftover live aquatic bait that has contacted infested waters should not be taken to uninfested waters.

Rinse: Before launching your boat into uninfested waters, thoroughly rinse and dry the hull, drive unit, livewells (and livewell pumping system), bilge, trailer, bait buckets, engine cooling system and other boat parts that got wet while in infested waters; use a hard spray from a garden hose.

If your boat was in infested waters for a long period of time, or if you find any attached adult mussels, use HOT (104 F) water instead of cold, or tow the boat through a do-it-yourself carwash and use the high pressure hot water to clean your boat. Do not use chlorine bleach or other environmentally unsound washing solutions.

Dry: Boats, motors and trailers should be allowed to dry thoroughly in the sun for at least five days before boating again in uninfested waters.

In Missouri, Zebra Mussels have been confirmed in Lake of the Ozarks, Bull Shoals Lake, Lake Taneycomo, Lake Lotawana, Smithville Lake, the Missouri and Mississippi Rivers and, potentially, in Truman Lake.