Habitat

Slow rivers, canals, docks, reservoirs, lakes, water pipes and cooling systems 

Key ID features

• Similar in shape to marine mussels, but smaller in size (usually about 30mm).

• Has distinctive ‘D’ shape shell, with stripes of light and dark bands of blue/brown/yellow-white bands.

Distribution

Common across England, rare in Wales and Scotland.

Impacts

It attaches in groups to anything solid underwater such as masonry, stones or wooden posts. Shells block pipework, and affect lock gates and other hard structures in water. Filters food from the water so efficiently that there is little food left in the water for mayfly larvae, caddisfly larvae, and small fish.

Do’s & Don’ts

• DO be a responsible water user.Follow the guidance and Check - Clean - Dry your kit and equipment.

More Information

For more information visit the GB Non-Native Species Secretariat website.