Michigan DNR: Invasive New Zealand Mudsnails Found In Shanty Creek In Antrim County

Press release from Michigan DNR:

Sept. 3, 2021

Contact: Lucas Nathan, 517-599-9323, or Joanne Foreman, 517-284-5814 Agency: Natural Resources

Sept. 3, 2021

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.

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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.

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What is being done?

Since the initial detection, the DNR and Department of Environment, Great Lakes, and Energy have incorporated mudsnail monitoring into their standard sampling procedures, increasing the potential for early detection in several rivers and streams each year.

Volunteers across the state, like those with the Grass River Natural Area Stream Watch, conduct regular monitoring of streams and rivers through the Michigan Clean Water Corps, or MiCorps, to determine stream health and look for invasive species. Other partners, including universities and cooperative invasive species management areas also engage in annual monitoring.

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What can you do?

The most important means of prevention is practicing good recreational hygiene. After a visit to one of Michigan's lakes, rivers or streams, be sure to clean, drain and dry your boat, trailer and equipment before heading to a new destination.

The New Zealand mudsnail's small size requires careful examination and cleaning of places where plants, mud or debris can be found on poles, nets, waders, boots, buckets, kayaks, canoes and flotation devices. Anything that has been in the water or at the water's edge should be inspected before it is packed or loaded.

The NZMS Collaborative offers these simple steps for cleaning boots and waders:

• Stomp and inspect as soon as you leave the water to remove attached debris.
• Brush waders, soles and laces to loosen remaining debris and mud.
• Spray boots and waders thoroughly with a disinfecting agent.
• Rinse after 20 minutes.
• Dry waders thoroughly before next use.

The short video, New Zealand Mudsnail Ecology and Fishing Gear Decontamination in Michigan, available at NZMSCollaborative.org, provides a demonstration of this cleaning technique as well as information on how to identify the invasive snail.

Additional information on New Zealand mudsnail, including how to report a suspected discovery of the snail, can be found at Michigan.gov/Invasives.

Michigan's Invasive Species Program is cooperatively implemented by the Department of Environment, Great Lakes, and Energy, the Department of Natural Resources, and the Department of Agriculture and Rural Development.

/Note to editors: Accompanying photos are available below for download. Suggested captions and credit information follow:

Map: Invaded river systems in Michigan, to date. Red dots indicate locations with confirmed presence of New Zealand mudsnails. Map courtesy of Jeremy Geist, Trout Unlimited.

Debris: New Zealand mudsnails are visible on this woody debris near the mouth of Shanty Creek. Photo courtesy of Emily Burke, Grass River Natural Area, Inc.

Mudsnails: A closer view of mudsnails is shown./

This press release was produced by the Michigan DNR. The views expressed here are the author’s own.