Invasive zebra mussels have made their way into Rainy Lake, posing an ecological threat to the popular haven for boaters and anglers that flanks the Minnesota-Canada border and is a gateway to Voyageurs National Park.
The Minnesota Department of Natural Resources confirmed Wednesday that zebra mussel larvae, known as veligers, were found in four of five water samples taken in July from the 360-square-mile lake near International Falls.
The DNR said the findings suggest the presence of a reproducing zebra mussel population.
About one-third of Rainy Lake is located within Voyageurs National Park. The zebra mussel larvae were found in waters outside the park boundary.
Zebra mussels are small mollusks, with a striped brown and tan, D-shaped shell. They usually cling to hard surfaces underwater, such as docks, trash, rocks or other shellfish.
About 3 percent of Minnesota lakes are infested with zebra mussels, although that number has been growing. The mussels can compete with native species for food and habitat, change the ecology of the lake, cut swimmers’ feet and cause damage to water intake pipes.
The DNR said it is in contact with the Canadian government, the National Park Service and the Bois Forte Band of Chippewa about the latest finding. The National Park Services collects samples from Rainy and adjoining lakes as part of a long-term monitoring program.
The DNR advises boaters and anglers to clean and drain watercraft and trailers and dispose of unwanted bait in the trash to prevent the spread of aquatic invasive species.
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