The invasive New Zealand mudsnail (Potamopyrgus antipodarum) was discovered in samples collected during a Water Action Volunteers training in Mt. Vernon Creek, the second such finding in the Upper Sugar River Watershed (Badger Mill Creek, 2016). The population abundance in Mt. Vernon Creek is uncertain at this time.
The impact of New Zealand mudsnails is not fully understood in the Midwest, though they are suspected to alter habitats and food chains in western states. Wisconsin DNR is actively monitoring for this species and working with Great Lakes states to assess populations.
New Zealand mudsnails are now known to exist in five Wisconsin rivers, three of those being in Dane County. USRWA encourages all users of any river to fully inspect and clean any gear that was in contact with the water. It is suspected that New Zealand munsnails are being transported through the boots and gear of anglers as each finding has been in a designated trout stream.