An independent laboratory has confirmed zebra mussel larvae in Garfield Lake in Hubbard County, according to a Minnesota Department of Natural Resources news release.
The lab provided photos of two zebra mussel larvae, called veligers, found in a water sample taken from the lake. Property owners on Garfield Lake hired the lab as part of their own monitoring.
Invasive species specialists from the DNR found no zebra mussels in the lake during a six-hour dive survey.
"I was involved in some of the on-the-water surveys with the DNR and we were not able to locate adult zebra mussels," said Bill DonCarlos, Hubbard County AIS Program Coordinator. "This simply means that the dive surveys were not successful in locating an established adult population of zebra mussels. I think that this is likely the very early stages of infestation."
More information is needed to assess the situation and will likely come with time, he said.
Located near Laporte, Garfield Lake is about 960 acres, with a maximum depth of 32 feet, according to the DNR. There is one public access.
It will be added to the state's "Infested Waters List" for zebra mussels, "with the provision that it may be removed from the list if future surveys continue to show no zebra mussels in the lake," the news release said.
Zebra mussels are native to Eastern Europe and western Russia. They were likely brought to North America in contaminated ballast water discharged from foreign ships. They were discovered in the Duluth harbor in 1989.
"Zebra mussels spread primarily by attaching to boat hulls, aquatic plants, docks and lifts. Adults can survive out of water for days under certain conditions," says Minnesota Sea Grant.
Adults range from a quarter-inch to 1.5 inches.
A DNR fact sheet explains that zebra mussels "attach to and smother native mussels" and "eat tiny food particles that they filter out of the water, which can reduce available food for larval fish and other animals and cause more aquatic vegetation to grow as a result of increased water clarity."