News Release

Zebra mussels confirmed in Spectacle Lake in Isanti County

October 7, 2019


The Minnesota Department of Natural Resources has confirmed multiple young of the year zebra mussels in Spectacle Lake in Isanti County, between the cities of Princeton and Cambridge. This is the first confirmation of zebra mussels in an Isanti County lake.

Following up on a citizen report, DNR invasive species specialists found multiple zebra mussels in two areas of the lake. All of the zebra mussels are less than one-half inch in length.

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.

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

Those who transport a dock or lift from a shoreline property to another location for storage or repair may need a permit.

To prevent the spread of aquatic invasive species DNR recommends 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 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.

More information is available at mndnr.gov/ais.