Single zebra mussel confirmed in Lake Harriet

Extensive multi-agency search showed no other zebra mussels

The Minnesota Department of Natural Resources has confirmed that a single zebra mussel was removed from Lake Harriet in Minneapolis. Minneapolis Park and Recreation Board (MPRB) staff reported one adult zebra mussel on a boat cover recovered from the bottom of the lake.

No additional zebra mussels were found during 67 hours of diving, snorkeling and wading searches involving the Minnehaha Creek Watershed District, MPRB, two MPRB contractors and the DNR. Lake Harriet will be added to the Infested Waters List for zebra mussels, with the provision that it may be removed from the list if future surveys continue to show no zebra mussels in the lake.

“We’re grateful that no zebra mussels were found during the extensive dive, snorkel and wading search of Lake Harriet,” said Heidi Wolf, DNR invasive species unit supervisor. “Strong partnerships and interagency cooperation are key, and we thank the Minneapolis Park and Recreation Board and the Minnehaha Creek Watershed District for their ongoing efforts.

“While we regret that Lake Harriet will be added to the Infested Waters List because one zebra mussel was confirmed, we’re hopeful that the lake may be removed from the list if future searches continue to show no zebra mussels in the lake,” Wolf said.

DNR invasive species specialist Keegan Lund said Lake Harriet will be carefully monitored the rest of this season and next year, but no treatment is necessary at this time. Lund said individual zebra mussels sometimes die after they are brought into a new lake, before they become established.

“There is a common misperception that zebra mussels are everywhere and that their spread is inevitable. The reality is, of Minnesota’s 11,842 lakes, fewer than 250, about 1.8 percent, are listed as infested with zebra mussels. More Minnesotans than ever before are following our state’s invasive species laws,” Lund said. “People spread zebra mussels, and people can prevent their spread.”

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

  • Clean watercraft 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, especially after leaving infested waters:

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

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 www.mndnr.gov/AIS.