The Common Slipper Limpet (Crepidula Fornicata) is a small marine shellfish native to North America’s Atlantic coast but now found in large numbers along European coasts, including the UK. It was introduced accidentally over a century ago, likely through imported oysters. Since then, it has spread quickly, becoming known as an “invasive species” because it can disrupt native marine life and habitats.

These limpets are particularly interesting because they form “stacks” or clusters on rocks, shells, or even other shellfish. A single stack can have up to twelve limpets piled on top of each other. This stacking behaviour is unique and related to their reproduction: slipper limpets are sequential hermaphrodites, meaning they can change their sex. The largest, oldest individuals at the bottom of the stack are female, while the younger, smaller limpets above them are male. If the female dies, one of the males changes to female, ensuring that the stack always has a reproductive pair.

Slipper limpets are filter feeders, which means they filter tiny bits of food, like plankton, from the water. However, in large numbers, they can change the structure of their environment. For instance, they trap particles in the water and deposit waste, which changes the seabed and can cover surfaces that other species need to grow. This behaviour affects native species, especially oysters and mussels, and can cause challenges for local fisheries. When they gather on oyster beds, slipper limpets can reduce the space available for oysters and affect the water flow needed for oysters to thrive, which impacts the health of these valuable shellfish.

In response to the slipper limpet’s spread, some regions have explored using them as a food source. Promoting these limpets in cuisine could offer an environmentally friendly way to control their population, potentially reducing their numbers while providing a new seafood option