Analysis of water samples collected as part of a long-term monitoring project have shown small but measurable numbers of zebra mussel larvae, called veligers, in Lake Vermilion, Lake Kabetogama, Crane Lake and Namakan Lake, all in St. Louis County.
Although the Minnesota Department of Natural Resources has not found adult zebra mussels in these lakes, the presence of veligers suggests reproducing zebra mussel populations. For that reason, these lakes will be listed as infested for zebra mussels. Sand Point Lake, connected to Namakan Lake by a wide channel, will also be listed for zebra mussels. The lakes will be closely monitored for veliger populations and any adult zebra mussels.
It is not unusual for large lakes especially to have confirmed veligers without confirmation of adult zebra mussels. For example, the DNR confirmed zebra mussel veligers in Rainy Lake in St. Louis County in 2021 but has not confirmed adult zebra mussels there.
Whether or not a lake has any invasive species, 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. 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.
Anyone who suspects a new infestation of an aquatic invasive plant or animal should note the exact location, take a photo or keep the specimen, and contact a Minnesota DNR aquatic invasive species specialist.
More information is available on the aquatic invasive species page of the DNR website.