News release: Zebra mussels confirmed in Big Stone Lake

October 16, 2023

The South Dakota Game, Fish and Parks Department has confirmed the presence of zebra mussels in Big Stone Lake, a long, narrow lake that extends 26 miles through Big Stone County in Minnesota and two South Dakota counties. Zebra mussels were found on multiple docks being removed from the lake at the end of the season, on both the South Dakota and Minnesota sides of the lake.

Big Stone Lake abuts Big Stone Lake State Park in Minnesota and Hartford Beach State Park in South Dakota. Big Stone Lake is the source of the Minnesota River. Zebra mussels were confirmed in the Minnesota River in 2017.

“Zebra mussels are sometimes first discovered in lakes when lake property owners or lake service provider businesses remove boats, docks and equipment from the water at the end of the season,” DNR Invasive Species Unit Supervisor Kelly Pennington said.

Lake property owners should carefully look for invasive species on the posts, wheels and underwater support bars of docks and lifts, as well as any parts of boats, pontoons and rafts that may have been submerged in water for an extended period.

Whether or not a lake has any invasive species, Minnesota law requires people to:

  • Clean watercraft, trailers and equipment to remove aquatic plants and prohibited invasive species.
  • Drain all water and leave drain plugs out during transport.
  • Dispose of unwanted bait in the trash.
  • Never release bait, plants or aquarium pets into Minnesota waters.
  • Dry docks, lifts and rafts for 21 days before moving them from one water body to another.

These additional steps reduce the risk of spreading aquatic invasive species:

  • Decontaminate watercraft and equipment – find free stations on the courtesy decontamination webpage of the DNR website.
  • Spray with high-pressure water or rinse with very hot water (120 degrees for at least two minutes or 140 degrees for at least 10 seconds).
  • Dry watercraft and equipment for at least five days before using in another water body.

People should contact a Minnesota DNR aquatic invasive species specialist if they think they have found zebra mussels or any other invasive species that was not already known to be in the water body.

More information is available on the aquatic invasive species webpage of the DNR website.

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