As the summer season heats up, a warning to boaters from the Wisconsin Department of Natural Resources: help stop the spread of zebra mussels in our lakes.

"There's really no control," says DNR Lakes Coordinator Susan Graham, "Once zebra mussels are infesting a water body there's really nothing we can do."

Zebra mussels are small clams that attach to hard surfaces or aquatic plants. They're harmful to a lake's environment and now it's confirmed they've infested Rock Lake in Jefferson County.

"It's going to alter the ecology of that lake," says Graham, "It's going to change things radically for people who use the lake or live on the lake."

People like Andy Buss. "People have to realize when they take their boat from lake to lake they have unique species per lake and it could be okay in their waters, but in somebody else's it could do some damage."

Allen Wych knows first hand how zebra mussels affect bodies of water. "I do a lot of fishing on the Mississippi river, and there are zebra mussels all over the place over there and they really take over the bottom."

That's why officials says it's important to draw a line in the sand here and keep the mussels from spreading.

"It's really unfortunate that the lakes have been infested but we want to do everything to try to prevent the spread to other lakes," says Graham.

If you've recently had your boat in Rock Lake or plan on trying out a new body of water, you can help prevent the spread of zebra mussels:

Inspect and remove all plants, animals, and mud from your boat.

Drain all water from your boat's live wells.

Dispose of unused bait in the trash, no the water.

And spray off your boat with hot or high pressure water. Or, dry the boat for 5 days before heading out again.

The DNR says almost certainly Lake Koshkonong will become infested because it's downstream. Next week they'll survey Lake Ripley as well.