New Zealand mud snails are tiny, but can pose a big problem. Each snail is about one eighth of an inch long but, like zebra and quagga mussels, they cluster in high density and reproduce quickly. The snails compete with native snails and other macro-invertebrates for food and space in waterways they invade.
Originally from New Zealand, the snails are now widespread in many western states and present in Wisconsin. They are easily transported and resilient, and can survive in damp environments for up to 26 days, said Sarah LeSage, aquatic invasive species coordinator with the Michigan Department of Environmental Quality.
The snails were originally discovered this summer between Gleason’s Landing and Baldwin in the Pere Marquette River — a popular stretch for fishers, canoeists and kayakers. Subsequent surveys have found the snails in more downstream spots.
“It was an unfortunate discovery that was more widespread than we’d originally known,” she said.