Zebra Mussels


  • Swimmers may cut their feet on the shells.
  • Clog water intake lines.
  • Attach to boat hulls and motors, reducing their performance.
  • Eat large volume of plankton that makes up base of the food web.
  • Illegal to transport on Minnesota roads – be sure to inspect your watercraft.

Description & Origin

  • Fingernail sized animals ¼ to 1-1/2 inches long and have D-shaped shells with alternating yellow and brownish colored stripes.
  • Native to lakes and rivers of southern Russia and Eastern Europe. They were transported in the ballast water of cargo ships and first discovered in the Great Lakes in 1988 and found in the Duluth/Superior Harbor in 1989.

Prevent their Spread

Mussels attach to boats, nets, docks, swim platforms, boat lifts, as well as aquatic plants. It is possible for adult mussels to survive out of water for several days in a cool, humid environment and spread from one water body to another. Microscopic larvae (veligers) can survive in water contained in bilges, bait buckets, ballast bags or any other water moved from an infested lake or river.

In Minnesota, the following steps must be made to prevent the spread of zebra mussels:

  • Clean weeds and debris from your boats and remove any attached zebra mussels.
  • Drain your boat, livewells and baitwells, and keep all drain plugs out while traveling.
  • Dispose of unwanted bait in the trash.
  • Dry docks, lifts, swim rafts and other equipment for at least 21 days before placing equipment into another water body.

Please refer to DNR’s fact sheet about zebra mussels and questions and answers about pilot projects to control zebra mussels in public waters.