Mystery Snails (Chinese, Japanese and Banded)
Chinese (Cipangopaludina chinensis), Japanese (C. japonica), and banded mystery snails (Viviparus georgianus) can form dense populations and outcompete native species for food and habitat in lakes and streams. They are intermediate hosts for parasitic worms and can transmit trematodes that kill waterfowl. Banded mystery snails (BMS) prey on fish embryos. Shells often litter shorelines and clog screens of water intakes.
Native to Asia, Chinese (CMS) and Japanese mystery snails (JMS) were shipped to California in the late 1800s for Asian seafood markets. CMS were likely released from aquaria into the Niagara River in the 1930s. JMS were stocked in Lake Erie as food for channel catfish in the 1940s. BMS were released into the Hudson River in 1867. Historically, they spread due to release by aquarists and consumers who purchased them from live food markets. Some speculate, without evidence, that young may spread by bait buckets and boat bilges. They can survive out of water for days by closing their shells. Eradicating mystery snails is nearly impossible. Your actions and your help in reporting new infestations are vital for preventing their spread.
Identify Mystery Snails
- Large golf ball-size snails with "trapdoor" (operculum missing when dead)
- Found in lakes and in slow moving rivers
- Dead snails foul shorelines and beaches during summer
What You Can Do
- Learn to recognize mystery snails.
- Contact a retailer for proper handling advice or possible returns.
- Give or trade with another aquarist, pond owner, or water gardener.
- Donate to a local aquarium society, school, or aquatic business.
- Seal aquatic plants in plastic bags and dispose in the trash.
- Contact a veterinarian or pet retailer for guidance on humane disposal of animals.
Report New Sightings — note exact location; place specimens in a sealed plastic bag or store in rubbing (isopropyl) alcohol; and call a Minnesota DNR Invasive Species Specialist (see www.mndnr.gov/invasives/contacts.html), 1-888-MINNDNR or (651) 259-5100; or the Minnesota Sea Grant Program in Duluth, (218) 726-8712.
Know the Rules!
Specimens are needed to confirm sightings, but some jurisdictions prohibit possession and transport of invasive aquatic plants and animals.Contact your local natural resource management agency for instructions. Unauthorized introduction of plants, fish, or invertebrates into the wild is illegal. Protect your property and our waters.