Chinese Mystery (trapdoor) Snail

Help Protect Our Lake from Aquatic Invasive Species

The Chinese mystery (trapdoor) snail is an invasive freshwater species that threatens the health of our lakes. Originally brought to North America as a food source in the 1890s, this snail has since spread widely across both the United States and Canada.

Once established, Chinese mystery snails compete aggressively with native clams, snails, and other filter-feeding species for food such as algae and plankton. This disrupts the natural aquatic food chain and can negatively affect overall lake health. They may also carry parasites that impact waterfowl.

This invasive snail has been confirmed in Lake Vernon and near the Camp Kitchen beach area on Fairy Lake. Residents and visitors are encouraged to monitor their shorelines and report any sightings.

How to Identify a Chinese Mystery Snail

Key features:

• Size: Typically 6–7 cm long

• Colour: Olive green, ranging to greenish-brown or reddish-brown

• Shell: 6–7 spirals (whorls)

• Has a hard “trapdoor” (operculum) that closes when threatened

• Can survive out of water for several days by sealing its shell

Reproduction:

• Females live up to 5 years

• Can produce up to 100 young in a single breeding season

• Juveniles are born fully formed with hard shells

• Breeding season typically runs June through October

Because of their high reproduction rate and lack of natural predators, these snails are extremely difficult to control once established.

Look-Alike Species

The banded mystery snail is another invasive species that closely resembles the Chinese mystery snail. It can be distinguished by 3–4 dark brown spiral bands on its shell.

How You Can Help Protect Our Lake

Prevent the Spread

It is provincial law that all watercraft and equipment must be cleaned before entering another body of water.

This includes:

• Boats, canoes, kayaks, sailboats, and trailers

• Docks, boat lifts, and boat ramps

• Water toys and recreational equipment

Remember to:

Clean • Drain • Dry

Also:

• Never release aquarium or pond water, fish, or plants into the lake.

Observe and Report

Early detection is critical.

If you suspect an invasive species:

• Report sightings to your Lake Association Environmental Coordinator

• Call the Invading Species Hotline: 1-800-563-7111

• Report online through EDDMapS

Learn More

Visit the Invasive Species Centre website to learn more about prevention and identification.

Work Together

Community participation makes a difference. Partner with your Lake Association to help monitor shorelines and safely remove invasive snails when found.

Photo credits: Ken-ichi Ueda; Lake Vernon Association