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

Dane County Asks Boaters, Lake Property Owners and Contractors to Watch for Zebra Mussels While Removing Piers and Boat Lifts

October 07, 2014
Pete Jopke, Dane County AIS Coordinator (608)-224-3733 Erika Hotchkiss, Marketing & Outreach Coordinator (608)-224-3762
Land & Water Resources

Along with falling leaves, apple season and Badger football, the fall season means that boating season is winding down and Yahara Lake levels will soon be lowered to winter operating levels.  Dane County aquatic invasive experts remind homeowners and contractors preparing to remove piers, boat lifts and rafts to be on the lookout for zebra mussels.


Why would anyone want to take a look at the bottom of the piers and other structures placed in the water?


“The clean equipment that gets installed every year provides an excellent home for aquatic invasive species (AIS) like zebra mussels to colonize,” explained Pete Jopke, Water Resources Planner for the Dane County Land and Water Resource Department.  “It’s often difficult to thoroughly inspect a structure while it’s in the water; however during removal anyone involved with the process can easily monitor for invasive species.”


AIS are non-native plants and animals that threaten Wisconsin’s waters by causing environmental and economic  harm. One example, 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 5% of Wisconsin lakes predicted to be suitable for zebra mussels. In Dane County, zebra mussels have been found in recent years in Lakes Monona, Mendota and Koshkonong.  Monitoring for zebra mussels in lakes Monona and Mendota has shown that earlier finds were isolated and the zebra mussels are not reproducing.  However, zebra mussel populations in the Lower Wisconsin River have remained steady. 


The high recreational use of the Yahara Chain of lakes and close proximity of other popular waterbodies with zebra mussels, increases the risk of aquatic invasives being transported by boat to Dane County waters.


To protect Dane County’s lakes and rivers, Sue Jones, Division Manager for the 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, Jones encourages citizens and contractors 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, Jones and Jopke ask:


  • Check that the invasive species has not been previously found on the waterbody by visiting the DNR zebra mussel page.  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 Pete Jopke,  Dane County  AIS Coordinator at (608) 224-3733 and deliver specimens.


“Responding quickly to new AIS detections is critical to help slow the spread into other waterbodies,” said Tim Campbell, AIS communications specialist for UW-Extension and the Wisconsin DNR. “It can also help control AIS within a body of water. Efforts of citizens statewide can help us achieve that.”


There are also specific laws lake property owners and contractors must follow to prevent the spread of AIS.  Prior to transporting any equipment Wisconsin law requires you to:


  • INSPECT boats, trailers, boat lifts, 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 invasive species regulations visit: keyword invasive species.


To read more about how Dane County is working to prevent the spread of aquatic invasives, please visit DaneWaters.



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