Starts with Ruth Lake in Crow Wing County
The Department of Natural Resources is initiating pilot projects aimed at treating recently discovered, small infestations of zebra mussels on Minnesota lakes. The first pilot project is the treatment of Ruth Lake in Crow Wing County.
The Ruth Lake infestation was confirmed in July, after a young snorkeler found a single zebra mussel under a rock. Subsequent surveys of the lake revealed about two dozen zebra mussels, all in the same small area. The pilot project treatment, using the pesticide Earth Tec QZ in a 3.4-acre section of the lake, will be paid for by the Ruth Lake Improvement Association.
Pilot projects are a new process designed by the DNR and the Minnesota Aquatic Invasive Species Research Center (MAISRC) at the University of Minnesota. They provide opportunities to test a specific, rapid protocol for treatment of zebra mussel infestations.
To be considered, an infestation must be limited in size and discovered early, and the DNR will require extensive pre- and post-treatment monitoring by the permittee to evaluate effectiveness. In most cases, the DNR will want to work with a lake association or similar stakeholder group.
“We’re hopeful that these pilot projects, combined with vigilant lake monitoring and adherence to clean, drain, dispose laws, can bring a heightened level of response to the challenges of aquatic invasive species in Minnesota,” said Ann Pierce, DNR section manager. “Our partnership with MAISRC assists our efforts to keep the percentage of Minnesota lakes with zebra mussels at the low level it is now, less than two percent.”
Christmas Lake treatment informs pilot projects
The effective treatment of a small, isolated zebra mussel infestation in Christmas Lake in April and May provided important groundwork for the new pilot project process. Shortly after the Christmas Lake infestation was confirmed, a combination of experimental, permitted pesticides was applied. A post-treatment survey showed no live zebra mussels in the treatment area and 10 outside the treatment area. A follow-up treatment was conducted across a slightly wider area. Subsequent searches of Christmas Lake, including the most recent dive survey Sept. 30, have shown no zebra mussels in the lake.
The rapid response treatment of Christmas Lake provided information to the DNR and MAISRC on zebra mussel sampling and treatment monitoring protocols. The information was useful in the development of the pilot project process. The treatments underscore the importance of vigilant monitoring and immediate reporting of zebra mussels. When an infestation is spotted and reported early, the lake may be a candidate for pilot project treatment.
This time of year, when cabins are being closed up, is an especially important time to check docks, lifts, and other equipment for zebra mussels. By law, docks and lifts must also dry for at least 21 days before putting them into another body of water, whether they are coming from an infested lake or not. Before leaving a lake, Minnesota’s aquatic invasive species laws require boaters and anglers to:
- Clean aquatic plants and animals from watercraft.
- Drain all water by removing drain plugs and keeping plugs out while transporting watercraft.
- Dispose of unwanted bait in the trash.
For more information on aquatic invasive species prevention and how to report a suspected infestation, visit the aquative species prevention page.