Update on zebra mussels found at Bde Maka Ska

Posted on 15 October, 2018

Aquatic invasive species professionals have been out inspecting Bde Maka Ska following the discovery of two juvenile zebra mussels on a sailboat as it was being removed from the lake for the season on Sunday, Sept. 30, 2018.

  • Staff from the Minneapolis Park and Recreation Board, Minnesota Department of Natural Resources and specialized contractors combed the north shoreline of Bde Maka Ska last week using scuba gear and waders to search habitat favored by zebra mussels. No additional specimens were found.
  • Water samples from five areas around the lake were tested using eDNA sampling. All five areas tested negative for the presence of zebra mussels. Additional eDNA analysis will likely occur next summer when zebra mussels would be actively reproducing.
  • The sailboat the zebra mussels were discovered on was moored at a buoy on Bde Maka Ska all season and did not leave the lake at any time, according to the owner of the boat.
  • The deadline for removing moored sailboats from Bde Maka Ska was Monday, Oct. 8. All sailboats were inspected as they were removed from the lake. No additional zebra mussels were observed.
  • All sailboat buoys will be removed and inspected this week.

“We were disappointed to find zebra mussels in Bde Maka Ska and are working hard to gather more information,” said MPRB Superintendent Mary Merrill. “We will assess potential courses of action once we have a clearer understanding of the extent and distribution of the population.”

It’s likely there’s a reproducing adult zebra mussel population in Bde Maka Ska because the specimens found were juveniles that appeared to be alive upon discovery. It’s not known how zebra mussels got into the lake and it’s likely it will never be known for certain.

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, and
  • 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 F for at least two minutes or 140 degrees F for at least 10 seconds).
  • Dry for at least five days.

In Bde Maka Ska, impacts from a zebra mussel infestation would include competing with native species for food and habitat and cutting the feet of swimmers.

People should contact an area DNR Aquatic Invasive Species Specialist if they think they have found zebra mussels or any other invasive species.

More information is available at mndnr.gov/ais.