Zebra mussels confirmed in Piersons Lake in Carver County

October 8, 2020

The Minnesota Department of Natural Resources has confirmed the presence of zebra mussels in Piersons Lake, near Victoria in Carver County.

After one juvenile zebra mussel was found on a settlement sampler near the Piersons Lake public access, DNR and Carver County staff conducted snorkel and scuba searches. Settlement samplers are solid surfaces placed in the water that people can check for attached zebra mussels. During the search, no additional zebra mussels were found, but a water sample revealed 260 zebra mussel larvae, called veligers.

The large number of veligers in the sample indicates that in-lake reproduction is likely occurring. Additional searches will be conducted this fall. Lake residents are asked to look for zebra mussels on docks and boat lifts when removing equipment.

While it’s always important to look for invasive species, it is especially beneficial at this time of year. Several new zebra mussel confirmations in recent years were initially reported by people removing docks, boats and boat lifts. Early detection and confirmation can help prevent spread to nearby lakes.

Minnesota law requires that docks and lifts remain out of the water for at least 21 days after they are removed from a waterbody before they can be placed into another body of water. In addition, anyone who transports a dock or lift from a shoreline property to another location for storage or repair may need a permit, to help prevent the spread of aquatic invasive species.

Whether or not a lake is listed for any invasive species, 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.