Description: A large bivalve (up to 12 cm long) which lives just below the surface of muddy sand. It is known to be long-lived, with reported ages to 400 years. The shell is broadly oval, with prominent ridges. The shell is a dull white but this is mostly covered with thick periostracum; in younger animals this is a glossy chestnut-brown and in older animals it ranges from greenish-brown to black.

Habitat: Sand and muddy sand; usually offshore.

Distribution: Found around all coasts of Britain and Ireland where there is suitable habitat.

Similar Species: There is only one species of Arctica found in Britain and Ireland.

Key Identification Features:

• Large bivalve, reaching up to 12 cm.
• Broadly oval shell with prominent ridges.
• Dull white shell which is mostly covered with periostracum.
• Periostracum glossy chestnut-brown in younger animals, green-brown to black in older specimens.

Distribution Map from NBN: Arctica islandica at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Arctica islandica at iNaturalist World Species Observations database.

WoRMS: Arctica islandica at World Register of Marine Species.