The Minnesota Department of Natural Resources has confirmed the presence of zebra mussels in Union Lake, near Erskine in Polk County; First Silver Lake, near the town of Battle Lake in Otter Tail County; and Heilberger Lake, near Erhard in Otter Tail County.

A lake property owner contacted the DNR after finding a zebra mussel attached to a native mussel in Union Lake. DNR staff found more than 15 zebra mussels near the public water access, which is more than a mile from the location of the initial discovery.

Union Lake has a pump that is used in certain high-water conditions. This pump already has a filter to prevent the dispersal of Eurasian watermilfoil, and it is not currently operating. The DNR will provide direction to the Sand Hill River Watershed District, which operates the pump, to ensure that any future pumping operations are modified to also meet filtration requirements to prevent the spread of zebra mussels downstream.

A First Silver Lake user brought two zebra mussels to a DNR office and provided details on the location where they were found. A DNR invasive species specialist found two zebra mussels on the public water access boat ramp, about three-quarters of a mile from the location of the initial report.

A lake property owner contacted the DNR after finding three zebra mussels attached to a native mussel in Heilberger Lake. A DNR invasive species specialist found five zebra mussels on the public water access boat ramp, about a quarter-mile from the location of the initial report.

While zebra mussels and other invasive species can be introduced to a lake via private docks and accesses, public accesses are typically the first to be surveyed for invasive species.

Whether or not a lake has any invasive species, Minnesota law requires people to:

• Clean watercraft, trailers and equipment to remove aquatic plants and prohibited invasive species.
• Drain all water and leave drain plugs out during transport.
• Dispose of unwanted bait in the trash.
• Never release bait, plants or aquarium pets into Minnesota waters.
• Dry docks, lifts and rafts for 21 days before moving them from one water body to another.

These additional steps reduce the risk of spreading aquatic invasive species:

• Decontaminate watercraft and equipment – find free stations on the courtesy decontamination page of the DNR website.
• Spray watercraft and equipment with high-pressure water or rinse with very hot water (120 degrees for at least two minutes or 140 degrees for at least 10 seconds).
• Dry watercraft and equipment for at least five days before using in another water body.

People should contact a Minnesota DNR aquatic invasive species specialist if they think they have found zebra mussels or any other invasive species that was not already known to be in the water body.

More information is available on the aquatic invasive species page of the DNR website.