Invasive New Zealand Mudsnails Detected in East Branch Au Sable River

Invasive New Zealand Mudsnails detected in east branch Au Sable River

Michigan DNR June 9, 2016

The DEQ and DNR recently received reports from Grand Valley State University confirming populations of invasive New Zealand Mudsnails in the east branch of the Au Sable River near Grayling Michigan.

New Zealand Mudsnails are considered an invasive species and are listed as a Prohibited Species in Michigan. These snails are only about 1/8 of an inch long and can be difficult to see. However, they often cluster in high densities and compete with native snails and other macroinvertebrates for food and space. 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. Where established, these snails can dominate the bottoms of rivers and streams and exhibit invasive qualities, outcompeting and displacing macroinvertebrates that are vital as food sources for many fish species. In addition, these invasive snails have no nutritional value for fish.

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