(Big Lake, MN) -- Zebra mussels have been found in two Sherburne County lakes. The Minnesota Department of Natural Resources says the invasive aquatic species have been confirmed in Big Lake and Mitchell Lake, two adjacent lakes in the city of Big Lake. The lakes are connected by a channel that allows boat traffic. Big Lake city staff discovered a zebra mussel on the fishing pier in Big Lake and D-N-R staff found zebra mussels near the public launch in Mitchell Lake. It's the second and third Sherburne County lake this year where zebra mussels have been discovered.