Gastropods · Littorinimorpha · Littorinidae

Common Periwinkle

Littorina littorea

Not Evaluated

It has not yet been assessed against the IUCN criteria. See full glossary

The common periwinkle — known in Spanish as bígaro común or caracolillo — is a gastropod mollusc of the family Littorinidae. It is edible and has been eaten since antiquity, and is an accepted commercial species in Spain. No subspecies are recognised.

Size

up to 5.2 cm

Lifespan

8 years

Diet

Herbivore

Feeds mainly on plants.

Social structure

Colony

Lives in large concentrations, often for breeding reasons.

Sighting difficulty

Unknown

OceanHerbivore Colonial Ocean Mollusc

21countries 23parks 24dive sites

Fun facts

Introduced accidentally into North America in the nineteenth century, it completely transformed the rocky shores of New England by cutting back the intertidal algae and leaving the rock bare.
It is one of the keystone species of the intertidal: how hard it grazes determines which algae dominate the rock.
It is the largest periwinkle on British shores, with a shell of up to 52 mm.
It reached North America from Europe in the mid-nineteenth century, probably in ships' stone ballast. It arrived in Canada around 1840, Maine in 1870 and Cape May, New Jersey, in 1888.
There it has reordered the New England shore: by grazing on young algae it competes with native periwinkles and reduces algal cover, changing the whole community.
Its development of intersex features is used as a biomarker of tributyltin pollution, the compound used in ships' antifouling paints.
Its shells hold a climate archive: analysis of those from Orkney middens has shown that in the Middle Ages they were gathered mainly in early spring, probably as a famine food.