Mystery Snails

Mystery Snails

Two types of mystery snails will be discussed here – Chinese mystery snails (CMS), and banded mystery snails (BMS).

Where are mystery snails from and how did they get here?
CMS are originally from Asia. They were brought to California as a food source, and spread to other parts of North America from there, likely as an aquarium release.
BMS are originally from the southeastern United States, usually in the Mississippi River system. It is popular in aquariums, and is most often spread through aquarium dumping.

Mystery snails get their “mysterious” names because they give live birth to fully developed young – unlike native snails that lay eggs. It takes only one impregnated snail to start a new colony

How do I identify mystery snails?
CMS are identified primarily by the size of their shell – they grow to be much larger than native snails. They are round and apple-shaped.

BMS are most easily identified by the horizontal stripes on their shells.

Please contact our Water Program Coordinator if you think you have found mystery snails.

How do mystery snails affect Wisconsin water bodies?
Both CMS and BMS are prolific reproducers and can form dense aggregations. They compete with native snails, and can be a nuisance on beaches and around docks.

 

What can be done once mystery snails enter a Wisconsin water body?
At the moment, there are no known methods of removing mystery snail populations. If your lake group chooses to hand harvest mystery snails, this activity must be conducted on a very large scale, and completed several times within a season, each year, in order to decrease snail populations. Harvested snails should never be thrown in another lake, or even onto land in case an animal transports the snail. Dispose of snails in a tied garbage bag, or let them dry out in a bucket for several weeks before disposing of the snails. Mystery snails can live outside of the waters for up to two weeks.