Nature Lab

Citizen Science

Show-Me Snails

Tiny snails that many of us overlook have become the focus of a joint project between MDC, the Missouri Department of Natural Resources (DNR), and the Missouri Stream Team. The reason? Snails are sensitive to pollutants, which makes them excellent indicators of water quality.

“Ammonia is highly toxic to mussels and snails,” says MDC Scientist Steve McMurray. “But snails can be even more intolerant of ammonia than mussels can be, and they can be found in streams that are too small to support mussels.”

Under the Clean Water Act, states are required to review their water quality standards every three years, and DNR is reviewing the standards for ammonia. Some ammonia occurs naturally in streams, but too much can cause problems. Knowing which streams have snails and mussels is key for knowing which areas need greater protections. While surveys for mussels have already been done, studies on snails in Missouri are few, so in 2020 when DNR reached out to MDC for snail data, MDC scientists called on the Stream Team for help, and the Show-Me Snails project was born.

“They reached out knowing that we have thousands of active water quality volunteers around the state,” says April Sevy, MDC’s volunteer programs coordinator.

Stream Team volunteers were already visiting streams, so putting snails into collection vials and sending them to MDC staff for identification was a simple task to add. “And if they don’t find any snails,” says Sevy, “that’s also very helpful data for us.”

Snails can live in the tiniest of streams, and “therefore those smaller water bodies deserve protection,” says McMurray. “This data will help DNR more confidently set the standards for ammonia.”

At a Glance

Missouri has 52 species of aquatic snails. They are divided into two main groups: gilled and pouched.

• Gilled snails absorb oxygen from the water through their gills, like fish.
• Pouched snails gulp air at the water’s surface and bring it down into the water with them (similar to holding air in lungs).
• Gilled snails are more sensitive to pollution.
• Show-Me Snails volunteers collect both types.

Thank you, volunteers!

The Show-Me Snails project wouldn’t be successful without volunteers. If you’re interested in volunteering, sign up for the Stream Team at mostreamteam.org and email StreamTeam@mdc.mo.gov to say you’d like to help with snail collections.

Learn more at short.mdc.mo.gov/424