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The Mountain-Prairie Region


U.S. Fish and Wildlife Service
134 Union Boulevard
Lakewood, Colorado 80228

May 10, 1999
Linda Drees 785-539-3474, x20
Sharon Rose 303-236-7917, x415


Until recently zebra mussels had never been found in the Missouri River. On April 12, 1999 power plant employees removed what they believed to be a zebra mussel from an intake structure traveling screen located on the Missouri River at river mile 716.8, 15 miles south of Sioux City, Iowa. The specimen was confirmed as a zebra mussel on April 20. Only one was found, but since its introduction into the United States in 1980s from what is believed to be ballast water from eastern Europe, the zebra mussel has rapidly spread. Approximately 20 states and several rivers have established populations of zebra mussels, generating over $3.1 billion in damages over 10 years to intake pipes, water filtration's equipment and electric generating plants. Appearance in the Missouri River opens up a tremendous new habitat to this non-native, destructive species.

The major pathway for zebra mussels to invade the west is not from the ballast water of large ocean-going ships but from boats, personal watercraft, and related equipment being moved from infested to uninfested waters. Without knowledge of the owners, zebra mussels attach to hulls, trailers, and other exposed locations on boats, boating equipment, and personal watercraft. Their free-living larva can enter motors, live wells, or other moist areas and may remain viable for more than 10 days when attached to boat hulls. Their adaptability, their lack of natural predators, and the propensity of boaters to move their boats from one body of water to another have contributed greatly to the rapid spread of zebra mussels throughout their current range.

Simple solutions by recreational boaters and anglers will prevent the spread of zebra mussels and other aquatic nuisance species. Inspect your boat (sailboats specifically check centerboard/bilge board wells, and keel boats should check the rudder post area), trailer (axles, runners, lights, rollers), and other boating equipment (anchors, water-ski or other towlines) and remove any plants, animals, and mud that are visible before leaving any waters. Drain water from the motor, livewell, bilge, and transom wells while on land before leaving any waters. Wash/dry your boat, tackle, downriggers, trailer, and other boating equipment to kill harmful species that were not visible at the boat launch. This can be done on your way home or once you have returned home. Choose one of the following before transporting to another water body. Rinse your boat and boating equipment with hot (> 40 degrees C or 104 degrees F) tap water; or spray your boat and trailer with high-pressure water; or dry your boat and equipment for at least 5 days.

The public can also be involved in cooperative prevention programs such as the 100th Meridian Initiative to Prevent the Western Spread of Zebra Mussels and the Western Regional Panel on Aquatic Nuisance Species, which are active in monitoring and preventing the spread of zebra mussels.

Voluntary boater education stations can also be found in each 100th Meridian state from North Dakota south to Texas during summer 1999. Trained personnel are available at these locations to teach boaters how to inspect their boats and remove harmful exotic species such as zebra mussels. For further information, contact Linda Drees, Invasive Species Coordinator, (785)539-3474, x 20 or

Zebra mussels are natives of the Black, Caspian and Aral Sea drainage basins and were first discovered in the U.S. in Lake St. Clair near Detroit, Michigan, in 1988. By 1990, zebra mussels had been found in all the Great Lakes. Over 40,000 eggs can be laid in one reproductive cycle and up to one million in a spawning season. Zebra mussels are filter feeders and are capable of filtering about one liter of water per day while feeding primarily on algae. Zebra mussel densities were as high as 700,000 m2 at one power plant in Michigan and the diameters of pipes have been reduced by two-thirds at water treatment facilities. Although there is little information on zebra mussels’ affect on irrigation, farms, and golf courses, these places could be likely candidates for infestations. Navigation and recreational boating can be affected by increased drag due to attached mussels. Small mussels can get into engine cooling systems causing overheating and damage. Beaches become fouled by decomposing mussel shells. Fishing gear can be fouled if left in the water for long periods. Deterioration of dock pilings has increased when they are encrusted with zebra mussels. Continued attachment of zebra mussels can cause corrosion of steel and concrete, affecting its structural integrity.

The U.S. Fish and Wildlife Service is the principal Federal agency responsible for conserving, protecting, and enhancing fish and wildlife and their habitats for the continuing benefit of the American people. The Service manages the 93-million-acre National Wildlife Refuge System comprising more than 500 national wildlife refuges, thousands of small wetlands, and other special management areas. It also operates 66 national fish hatcheries and 78 ecological services field stations. The agency enforces Federal wildlife laws, administers the Endangered Species Act, manages migratory bird populations, restores nationally significant fisheries, conserves and restores wildlife habitat such as wetlands, and helps foreign governments with their conservation efforts. It also oversees the Federal Aid program that distributes hundreds of millions of dollars in excise taxes on fishing and hunting equipment to state wildlife agencies.

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