Ocean quahog

Ocean quahog

5-Ocean_quahog-(D)-Ocean_quahog--(copyright-Jon_B_H)

Ocean quahog

Illustration: Jón Baldur Hlíðberg

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Ocean quahog fishing grounds in 1998-2011 (t/nm2), all gear combines. dark areas indicate highest catches.

Source: The Marine Research Institute

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Ocean quahog catch (t) in Icelandic waters

Source: Statistics Iceland

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Ocean quahog catch (t) by month

Source: Statistics Iceland, weight reports

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Value of exported ocean quahog products by main countries in 2008 (FOB million ISK)

Source: Statistics Iceland

Scientific: Arctica islandica. English: Ocean quahog, Icelandic cyprine, black clam, black quahog. Icelandic: Kúfiskur, kúskel. For more languages see the Marine Animal Dictionary.

Biology and distribution

The ocean quahog is large bivalve that can reach a height of up to 10 cm. It grows rather rapidly during the first years, but the growth slows down after it reaches sexual maturity at the age of about 20 years, at the size of 6 to 7 cm. The ocean quahog can live to a very old age; the oldest individual measured in Icelandic waters was estimated to be about 400 years old. This makes the ocean quahog the longest lived animal on earth. The ocean quahog lives buried in the sediment so only a small opening of the shell is visible. It feeds by filtering phytoplankton and organic material from the sea,

The ocean quahog is found all around Iceland on sand or mud bottom at depths of 5 to 50 m. It also occurs deeper. Where conditions are favourable, the density can reach up to 88 shells per m2, or 8 kg. The total stock size estimated in Icelandic waters is more than 1 million tonnes. The ocean quahog has a wide global distribution. It is found in European waters from the White Sea in the north to the Strait of Gibraltar in the south. It is also around the Faroe Islands, and from Labrador to Virginia in North America.

Catch and fishing methods

The fishery for ocean quahog is very specialized and have fluctuated greatly in the past. Due to marketing reasons the fisheries have been negligible for the last years. Historically the ocean quahog has also been fished with smaller dredges for bait in the cod fisheries.

Stock status

See the Marine Research institute

Processing and markets

The ocean quahog catch is frozen and exported to USA where it is mostly processed into clam chowder soup. A small local market also exists for ocean quahog as bait.

References and further information

Hreiðar Þór Valtýsson, University of Akureyri