Mystery Snails
Chinese Mystery Snails (Cipangopaludina chinensis Reeve)
Chinese mystery snails are non-native (different than invasive) snails that have been identified in many Wisconsin Lakes, Wheeler included. They originated from Eastern Asia and were brought to America as a food source and as filter feeders.
There is not a lot yet known about these species, especially their effects on ecosystems. However, they have been known to clog propellers and decrease the native snail population (Wisconsin Sea Grant). The mystery snail has a thick shell, a right-opening shell, and hard operculum (a trap door cover which protects the soft flesh inside). Please note that the operculum is gone when the snail is dead and/or the shell is empty. These qualities make them less likely to be eaten by predators and more resistant to chemical treatments since their trap door cover prevents exposure.
They prefer silty and mucky habitats in which they consume dead organic matter (OM). This in turn makes them difficult to remove. The best way to remove them is to dispose of them if they wash up on your shore.
Some publications:
Juvenile Chinese Mystery Snails
Example of the operculum
Banded Mystery Snails(Vivaparus georgianus)
These non-native snails originated from the southeastern United States and are commonly sold in the aquarium trade. Like the Chinese Mystery Snails, they prefer the sandy/mucky bottom of lakes and slow-moving streams where they can filter feed on dead OM.
Banded Mystery Snails have a right-opening shell with 4 reddish bands and a hard operculum (please note that the operculum is gone when the snail is dead and/or the shell is empty).
Banded Mystery snails decrease native snail populations, invade largemouth bass nesting sites, and transmit parasites to fish and wildlife (Wisconsin Sea Grant). Removal techniques are the same as the Chinese Mystery Snails, just remove them from the lake and from your shore when you notice them.
Check out this website for more information on Banded Mystery Snails.