Zebra mussels have been confirmed in 29 lakes and nine rivers in Minnesota, and are suspected in 30 additional connected lakes.

The mussels accumulate on boats and clog motors, litter beaches with razor-sharp shells, and change the ecology of fisheries by consuming food that small fish need to survive.

They can spread easily, carried in bait buckets or on boats.

Some people are urging mandatory inspections and boat washing to keep the mussels from being transported carelessly or inadvertently by boaters who move from lake to lake.