HACKENSACK -- The Minnesota Department of Natural Resources confirmed zebra mussel larvae in a water sample taken from Ten Mile Lake near Hackensack in Cass County.

A DNR research scientist identified 17 microscopic zebra mussel larvae, called veligers, in a water sample taken from the lake in September. While no adult or juvenile zebra mussels have been reported, the number of veligers indicates a reproducing population.

Ten Mile Lake will be added to the infested waters list for zebra mussels so people who harvest bait or fish commercially take necessary precautions. Other lake users should follow the same “Clean, Drain, Dispose” steps that are always legally required on all water bodies, regardless of whether they are on the infested waters list, the DNR stated.

Lake property owners should carefully check boats and trailers, docks and lifts, and all other water-related equipment for invasive species when removing equipment for seasonal storage.

The DNR noted it is especially important to follow Minnesota’s law and keep docks and boat lifts out of the water for at least 21 days before putting them into another body of water.

Anyone transporting 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.

The DNR recommends these steps for lake property owners:

  • Look 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.

  • Hire DNR-permitted lake service provider businesses to install or remove boats, docks, lifts and other water-related equipment. These businesses have attended training on Minnesota’s aquatic invasive species laws and many have experience identifying and removing invasive species.

People should contact an area DNR aquatic invasive species specialist if they think they have found zebra mussels or any other invasive species.

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 body of water:

  • 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), and

  • Dry for at least five days.

The zebra mussel is native to Eastern Europe and western Russia. The species was unintentionally introduced into the United States’ Great Lakes through the discharge of contaminated cargo ship ballast water. They were first discovered in the Great Lakes in 1988 and were first confirmed in the Duluth/Superior Harbor in 1989.

A single zebra mussel can filter one quart of water per day while feeding primarily on algae. They live underwater, attached to natural and manmade substrates such as rocks, wood, plants, native mussels, pipes, docks, boat lifts, swim rafts, moored watercraft and other debris. A female can produce 100,000 to 500,000 eggs per year. Fertilized eggs develop into microscopic, free-living larvae that form shells. After two to three weeks, the veligers settle and attach to a firm surface using tiny fibers called byssal threads. Beds of zebra mussels can reach tens of thousands within a single square yard.

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.

More information is available at mndnr.gov/ais.