News Release

Zebra mussels confirmed in Lake Oscar in Douglas County

July 23, 2019


The Minnesota Department of Natural Resources has confirmed reports of zebra mussels in Lake Oscar in Douglas County. 

A lake property owner contacted the lake association after finding a three-quarter-inch adult zebra mussel. The lake association reported it to Douglas County aquatic invasive species staff who, in turn, contacted the DNR. DNR divers found a total of 78 adult zebra mussels in four locations on the lake.

Whether or not a lake is listed as infested, Minnesota law requires boaters and anglers to:

  • Clean watercraft and trailers of aquatic plants and prohibited invasive species.
  • Drain all water by removing drain plugs and keeping them out during transport.
  • Dispose of unwanted bait in the trash.

Some invasive species are small and difficult to see at the access. To remove or kill them, take one or more of the following precautions before moving to another waterbody:

  • Spray with high-pressure water.
  • Rinse with very hot water (120 degrees for at least two minutes or 140 degrees for at least 10 seconds).
  • Dry for at least five days.

Zebra mussels can compete with native species for food and habitat, cut the feet of swimmers, reduce the performance of boat motors, and cause expensive damage to water intake pipes.

People should contact an area DNR aquatic invasive species specialist if they think they have found zebra mussels or any other invasive species that has not already been confirmed in a lake.

More information is available at mndnr.gov/ais.