Anglers urged to step up prevention efforts during salmon season
Invasive New Zealand mudsnails have been detected at the mouth of Shanty Creek, a tributary of the Grass River in Antrim County. The snails were found during routine monitoring in May by the Grass River Natural Area Stream Watch project and confirmed through DNA analysis by Oakland University in August.
New Zealand mudsnails were first discovered in the United States in Idaho’s Snake River in 1987. Since then, the snails have spread throughout the western states and into areas of the Great Lakes by attaching themselves to boats, waders and equipment.
The Grass River is now the sixth river system in Michigan known to be infested by the mudsnails. Their discovery in the Pere Marquette River in August 2015 signaled the first detection in a Michigan inland waterway. In 2016, populations were confirmed in the Boardman and Au Sable rivers. By 2017, the invasive snails were found in the Upper Manistee and Pine rivers.
Michigan’s salmon season, which peaks in September and October, draws thousands of anglers to Michigan’s premier rivers.
“This is a time when people are likely to visit multiple rivers and streams over a few days,” said Lucas Nathan, Michigan Department of Natural Resources aquatic invasive species coordinator. “If they are not cleaning equipment thoroughly each time, there is a potential to introduce New Zealand mudsnails into new waters.”
What harm can a snail do?
This brown to black, one-eighth-inch long mudsnail, a native of New Zealand, is considered invasive and is prohibited in Michigan due to the environmental harm it can cause to rivers, streams and lakes. Because the snail reproduces by cloning (females develop complete embryos without fertilization), a single snail can start an entire population.
| One snail can produce over 200 young in a year. Since few natural predators or parasites of this species exist in North America, their numbers grow rapidly each year. In some locations in western states, researchers have documented snails reaching densities of 300,000 per square meter. With that many mudsnails, food for other stream invertebrate populations can become scarce. Read more |
