Natural England - Ocean quahog

Ocean quahog

Arctica islandica

Ocean quahog © Paul Kay

Ocean quahog © Paul Kay

The Ocean quahog is a typical cockle-shaped bivalve, and the two halves of its hinged, rounded shell are thick, glossy and dark brown in colour. It is a long-lived animal and is quite large for its kind, growing up to 13cm across.

Ocean quahogs can be found from just below the low water level to depths of about 500m. They live buried in sand and muddy sand, often with their shells entirely hidden and just a small tube extending up to the surface of the seabed. The tube is a siphon that keeps water flowing across the animal, so that it can breathe, capture food, and expel waste.

People do eat quahogs, although this is more common in North America, Iceland and Norway than in the UK. Commercial fisheries for the bivalve suddenly increased enormously in the mid-1970s, and have remained at those levels ever since.

Ocean quahogs grow very slowly, and can take up to 50 years to reach market size. They are at particular risk from bottom fishing gear, and, like other slow-growing animals, once their numbers have been reduced the populations can take a long time to recover.

Ocean quahogs are also an important food source for cod.

Other common names

Icelandic cyprine, Iceland cyprina

Brief description of European distribution

Ocean quahogs are found all around, and offshore from, British and Irish coasts, and the European range extends from Norway to the Bay of Biscay.

Conservation status / need

OSPAR List of Threatened and/or Declining Species and Habitats (Region II – Greater North Sea)

In Wales, ocean quahogs are a species of principal importance for the purpose of conservation biodiversity under the Natural Environment and Rural Communities Act 2006

Further information sources

Icelandic cyprine - Arctica islandicaexternal link Marine life information network

Arctica islandicaexternal link Conchological Society of Great Britain and Ireland

Arctica islandicaexternal link Food and Agriculture Organization of the United Nations

Arctica islandicaexternal link World register of marine species (WoRMS)

Arctica islandicaexternal link Encyclopedia of Marine Life of Britain and Ireland

Interesting fact

Ocean quahogs can live to more than 400 years old.