Invasive zebra mussels have been confirmed in Lake Byllesby, the largest lake in southern Dakota County.

According to the Minnesota Department of Natural Resources, the nuisance mollusks were first detected in August 2023, when one adult zebra mussel was found by DNR staff working with native mussels. Subsequent surveys did not indicate more zebra mussels or evidence of reproduction. However, water samples this summer found four mussel larvae, called veligers, which is indicative of zebra mussel reproduction.

Located on the border of Dakota and Goodhue counties, the 1,400-acre Lake Byllesby is a reservoir on the Cannon River.

The DNR says state law requires boaters, anglers and waterfront property owners to take a variety of actions to prevent the spread of zebra mussels, regardless of whether a lake has an infestation.

Minnesotans should contact the DNR if they believe they have found zebra mussels or any other invasive species that was not already known to be in the water body.

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.