Zebra Mussel Larvae Confirmed in Big Marine Lake
Invasive clams detected for first time in the lake in lower St. Croix watershed.
Minnesota Department of Natural Resources, September 2, 2025.
Non-native zebra mussels cling to a native pocketbook mussel found in the St. Croix River at Prescott. (photo by Greg Seitz, St. Croix 360)
The Minnesota Department of Natural Resources has confirmed zebra mussels and zebra mussel larvae in Cedar Lake, near New Prague in Scott County, and Big Marine Lake, near Forest Lake in Washington County.
A lake service provider notified the DNR after finding zebra mussels attached to a dock on Cedar Lake. A contract diver found no adult zebra mussels in Cedar Lake, but water samples analyzed by the DNR contained zebra mussel larvae, called veligers.
DNR and conservation district watercraft inspection staff found adult zebra mussels on two watercraft exiting Big Marine Lake at different locations. No adult zebra mussels were found during subsequent dive searches, but water samples analyzed by the DNR contained veligers.