Invasive zebra mussels were discovered in two more Ramsey County lakes in the waning months of summer, bringing the number of county lakes infested or suspected of infestation to 10, according to the Minnesota Department of Natural Resources.
A diver hired by Ramsey County to conduct an early detection survey found a mussel last month near the public access on Long Lake in New Brighton. In August, a volunteer trained in invasive species detection found zebra mussels near the public access at Lake McCarrons in Roseville.
DNR staffers in 2018 confirmed the existence of zebra mussels in Bald Eagle Lake in White Bear Township, the east metro’s most popular muskie lake, and Lake Johanna in Arden Hills.
Other infested Ramsey County lakes are Charley and Pleasant lakes, North Oaks; Sucker and East and West Vadnais lakes, Vadnais Heights; and White Bear Lake.
Despite the new infestations, prevention and education efforts are continuing, said Justin Townsend, Ramsey County’s aquatic invasive species coordinator. The county will host a free forum on aquatic invasive species at 6:30 p.m. on Nov. 21 at the Ramsey County Public Works building in Arden Hills.
“We need to change people’s behavior and we can do that,” Townsend said. “Our point is to get people engaged and involved with what they can do.”
There’s no viable treatment once a lake has been infested, but DNR supervisor Heidi Wolf said they’re now exploring some pesticide treatments when the infestation is caught early.
Since 2015, the county has hired divers to regularly survey for the mussels and other invasive species at 17 area lakes that have public boat launches.
Zebra mussels, native to Eastern Europe and western Russia, likely were brought to North America in the ballast water of ships and were discovered in Lake Erie in 1988, according to the DNR website.
Named for their yellow and brown striped shells, they range in size from ¼ to 1½ inches long and are sharp enough to cut a swimmer’s feet. Unlike native mussels, they attach themselves to hard surfaces in the water including boat motors and hulls, clogging irrigation intakes.
Zebra mussels cause problems for native plants and animals, boaters and swimmers. They can smother native mussels and filter out tiny nutrient particles until the water becomes “gin clear,” reducing available food for native plants and animals. That filtering can also increase the growth of aquatic vegetation.
As of October 2018, the DNR had confirmed zebra mussels in 180 state lakes and wetlands and officials suspect they could be living in 167 additional bodies of water closely connected to infested waterways.
The mussels can be transported while attached to equipment or boat hulls or in lake water that contains mussels in their microscopic stage, Wolf said.
“You cannot see them with a naked eye, but they are in the water,” she said.