New Zealand Mudsnail Found for 2nd Time in Dane County

The invasive New Zealand mudsnail (Potamopyrgus antipodarum) has been recently discovered for the first time in Badger Mill Creek at the Highway 69 bridge crossing, near Verona, WI. The snail was initially identified by a Madison Metropolitan Sewerage District (MMSD) monitor during routine monitoring conducted on the creek, which begins in the Town of Middleton, and receives effluent from MMSD sewage outfall near Badger Prairie in Verona. It subsequently feeds into the Sugar River at Riverside Road, near the initial Highway 69 discovery. Regular monitoring helps MMSD gauge the effects of their discharge on the creek and any unexpected, harmful changes.

Response efforts are now being initiated by a partnership of groups including Wisconsin Department of Natural Resources, River Alliance of Wisconsin, Upper Sugar River Watershed Association, Southern Wisconsin Trout Unlimited and Southwest Badger Resource Conservation & Development Council.

Upon the discovery of New Zealand mudsnail on Badger Mill Creek, samples were provided to the Wisconsin Department of Natural Resources and verified by a taxonomic expert. Prior to this discovery, Black Earth Creek in Western Dane County was the only inland stream in Wisconsin to have a known population of the invasive snail. Subsequent stream monitoring by DNR staff confirmed the presence of these snails at two additional sites on Badger Mill Creek.

The New Zealand mudsnail is highly invasive in Western states and is known to reach high abundances, outcompete native stream insects that serve as food for fish, and change nutrient dynamics in streams. Its impacts can vary and it is uncertain what impacts this invasive species will have on streams in Wisconsin. Bobbi Peckarsky of the University of Wisconsin, Departments of Zoology & Entomology has been analyzing data collected on Black Earth Creek since the initial discovery of New Zealand mudsnail there. “Data show populations of these snails are growing fast at three sites on Black Earth Creek, but more time and further study are needed to fully understand the impacts proliferation of this invasive snail will have on other aspects of these streams, such as stream metabolism, plant growth, macroinvertebrate and fish communities,” Peckarsky stated.

Stream anglers, volunteer and professional water quality monitors, and paddlers play an important role in preventing the spread of the New Zealand mudsnail. Here’s what you can do to help:

• All water users are asked to inspect and carefully clean all gear, including waders, boots, nets, and boats, prior to leaving any stream.
• People who wade a stream for any reason should also use a brush to scrub their boots and waders, and rinse gear with clean water.
• Freezing gear is another option to further reduce the risk of transporting New Zealand mudsnails to other streams.
• When possible, anglers should avoid the use of felt soled wading boots to decrease the likelihood of transporting other harmful organisms to Wisconsin streams as well.
• Contact us if you’d like to volunteer in the coming months to help build boot brush stations and assist with further monitoring.

The River Alliance of Wisconsin, Upper Sugar River Watershed Association, Southern Wisconsin Chapter of Trout Unlimited, and Southwest Badger Resource Conservation & Development Council are currently teaming up with the DNR to install signage and boot brush stations across Badger Mill Creek and the Sugar River watershed to assist river users in cleaning their gear.

Volunteers will be needed over the coming months to build these stations and assist with further monitoring. Contact Amanda Perdzock at the River Alliance of Wisconsin, Upper Sugar Watershed Association or Southern Wisconsin Chapter of Trout Unlimited to become a part of these response efforts.