Seal of Dane County County of Dane
Dane County Land & Water Resources Department

Dane County Office of Lakes and Watersheds Asks For Lake Residents’ Help - Fall is best time to look for zebra mussels as boats, piers removed for winter

October 21, 2013
Sue Jones, 608-224-3764, or Pete Jopke, 608-224-3733,
Land & Water Resources

(Madison, WI)As the temperatures fall and lake residents begin to remove piers, docks and boats from the water, the Dane County Office of Lakes and Watersheds reminds them to check for any new invaders that might have attached themselves to the equipment while it was submerged over the summer.


Aquatic invasive species (AIS) are non-native plants and animals that threaten Wisconsin’s lakes and river systems by causing environmental and economic harm. Zebra mussels can clog water intakes and pipes, encrust piers, boats, and motors, and their sharp shells can cut the feet of swimmers.


Zebra mussels have been found in less than five percent of Wisconsin lakes predicted to be suitable for zebra mussels. In Dane County, zebra mussels have been confirmed in the Lower Wisconsin River and previously reported in Lake Monona although they have not been seen since 2005.


“With our proximity to other infested waterbodies in this part of the state, we are highly vulnerable to zebra mussels,” said Sue Jones, Director of Dane County’s Office of Lakes and Watersheds.  “The Yahara Chain of Lakes sees some of the highest recreational use in the state and we know boaters move from lake to lake. To protect the rest of Dane County’s lakes and rivers, the Dane County Office of Lakes and Watersheds is asking landowners and contractors to carefully examine piers, boats, boatlifts, rafts, and any other equipment that has been in the water for a prolonged period of time for signs of zebra mussels during removal.”


In addition to a visual inspection, citizens/contractors are encouraged to feel smooth surfaces of equipment to check for juvenile zebra mussels as they may have a “sand-paper like” feel and are often invisible to the human eye. If zebra mussels or other new invasive species are found:

  • Check that the invasive species has not been previously found on the waterbody by visiting
  • Note the exact location where the animal was found.
  • Take a digital photo of the animal in the setting where it was found (if possible). Then collect up to five specimens of varying sizes. Place in a jar with water; put on ice and transport to refrigerator.
  • Contact Susan Graham, DNR AIS Coordinator at (608) 275-3329 and deliver specimens.

Responding quickly to new AIS detections is critical to help curb the spread into other waterbodies.

There are also specific laws lake users, property owners and contractors must follow to prevent the spread of aquatic invasive species.  Prior to removing equipment from the water Wisconsin law requires that you:

  • INSPECT boats, trailers, boatlifts, piers, rafts and equipment.
  • REMOVE all attached aquatic plants and animals.
  • DRAIN all water from boats, vehicles, and equipment.


To learn more about zebra mussels or Wisconsin aquatic invasives species regulations visit: keyword “invasive species” and the Dane County Office of Lakes and Watersheds at



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