Photograph courtesy of the U.S. Geological Survey

Zebra mussels detected in Williamstown Lake

​FRANKFORT, Ky. (Nov. 23, 2022) — Biologists with the Kentucky Department of Fish and Wildlife Resources recently confirmed the presence of invasive zebra mussels in a popular northern Kentucky lake.

Biologists visited Williamstown Lake on Nov. 16 and concluded zebra mussels were present in the Grant County water body. Only mature adults were observed at the time.

Freshwater mussels are clam-like animals. Numerous species native to Kentucky reside in lakes and streams across the commonwealth and are important for keeping water resources clean, aiding in nutrient cycling and contributing to the overall health and complexity of aquatic ecosystems. They take in water to glean organic particles for food and simultaneously filter out sediments and other pollutants. They also serve as a source of food and habitat structure for other aquatic organisms.

In recent decades, many of Kentucky's native mussel species have become imperiled due to habitat loss, water pollution and competition with invasive species; causing many to become federally listed as threatened or endangered.

Zebra mussels compete with native fish and mussel species and can impair water and power infrastructure, as well as damage property and habitat. It's possible zebra mussels were introduced into Williamstown Lake from boats that had not been properly cleaned and dried after being used in another water body.

Water samples taken from the lake will be tested to determine if the mineral content is conducive to zebra mussel reproduction. Kentucky Fish and Wildlife will continue to monitor the zebra mussel population in the lake, and surrounding water bodies and streams also will be checked for zebra mussels.

Zebra mussels have been found in locations throughout Kentucky, thriving in slow-moving lakes and rivers. Easily identifiable with small, pointed shells exhibiting a zebra-like pattern of stripes, they attach to any solid submerged surface in clusters, reproduce rapidly and pose a serious threat to native freshwater mussel populations and other aquatic animals.

The nearby Licking River is home to some of the state's rarest native mussels. 

“Vigilance by boaters, anglers and the broader community is necessary to help prevent the spread of invasive zebra mussels and other aquatic nuisance species," said Monte McGregor, fisheries research biologist and lead malacologist with Kentucky Fish and Wildlife. “Zebra mussels can hitch a ride on boats and other equipment or objects that have been submerged in water from an infected location, and may be released inadvertently into the wild from home aquariums or other objects like bait buckets."

Both adult zebra mussels and the larval form, known as veligers, can be transported into other bodies of water. Veligers are invisible to the naked eye and can survive in trapped water or may cling to plant fragments or objects that came into contact with water. Adult zebra mussels can live up to 10 days out of the water and can be transported to another water body while attached to a boat or other equipment.

  • To help stop the harmful transfer of zebra mussels between bodies of water, Kentucky Fish and Wildlife recommends the following simple steps:
  • Clean boats, trailers and gear by removing all plants, animals and foreign objects.
  • Drain all water from boats, including the motor, bilge, live wells and bait buckets, before leaving the shore, ramp or parking area of a lake or river.
  • Dry boats, trailers and gear for at least five days before entering another water body. If unable to let items dry for at least five days, rinse equipment and watercraft (with high pressure, hot water when possible) and wipe with a towel before reuse.
  • Dispose of unwanted live bait and worms in the trash.
  • Never introduce fish, plants, crayfish, snails or mussels from one body of water to another.

For more information about zebra mussels and other invasive aquatic species, visit Kentucky Fish and Wildlife's website at or call 1-800-858-1549, 8 a.m. – 4:30 p.m. (Eastern) weekdays, excluding holidays.

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