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
Ocean quahogs are found all around British and Irish coasts and
in offshore waters. The European range extends from Norway to the
Bay of Biscay.
OSPAR list of threatened and/or declining species and habitats
(Region II - Greater North Sea)
OSPAR List of Threatened and/or Declining Species and
OSPAR Commission –
Background Document for ocean quahog Arctica
Food and Agriculture
Life Information Network
World Register of Marine Species