The Minnesota Department of Natural Resources has confirmed reports of zebra mussels in Long Lake, near Park Rapids in Hubbard County, and Pickerel Lake, near Maine in Otter Tail County.

A trained invasive species detector found a single zebra mussel on a plant rake when conducting routine sampling on Long Lake. A subsequent dive search revealed two adult zebra mussels near the south public access and fishing pier on Long Lake. A DNR invasive species specialist said the specimens were breeding adults that were likely in the lake prior to this year. 

The Pickerel Lake report was filed by an Otter Tail County Sheriff’s Office deputy after a lake user sent him photos of a zebra mussel attached to a native clam in the lake. DNR invasive species specialists conducted two follow-up searches and found a single adult zebra mussel, one and one-quarter inch in length, about a half-mile from the location of the original report.

“It’s helpful that lake users contact us when they find what might be a new invasive species to a lake,” DNR Invasive Species Unit supervisor Heidi Wolf said. “Early detection is important, because it can help prevent spread to other lakes.”

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 a Minnesota 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.