Invertebrates
Slipper Limpet
Crepidula fornicata · also called common slipper shell
On the shell of a live oyster in a muddy estuary, a stack of slipper limpets sits one on top of another, the bottom ones female and the top ones male.
Overview
The slipper limpet, Crepidula fornicata, is a sea snail from the east coast of North America that has become an invader in the sheltered coastal waters of north-western Europe. Its stacking, sex change, and smothering of shellfish beds make it one of the best-known marine invaders on European shores.
A snail that lives in a tower
By stacking up in chains, slipper limpets guarantee that every animal in the tower has a mate, with the oldest and biggest at the bottom.
Status
Not Evaluated, and invasive in Europe.
Slipper Limpet: common questions
Is a slipper limpet a true limpet?
No, it is a sea snail whose shell looks like a limpet, with a small internal shelf like the seat of a slipper.
Why do slipper limpets live in stacks?
They settle in chains of several animals, one on top of another, with the bottom ones female and the top ones male.
How did it reach Europe?
It was brought from North America in the late 1800s, probably with imported oysters.
Why is it a problem?
It forms dense beds on shellfish beds, where it competes for food and space and smothers the seabed with mud.