Greenland shark

Greenland shark

5-Greenland_shark__2-Shark_and_cod_fisheries-(D)-Greenland_shark--(copyright-Jon_B_H)

Greenland shark

Illustration: Jˇn Baldur HlÝ­berg

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Greenland shark catch (t) in Icelandic waters

Source: ICES, Statistics Iceland

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Greenland shark catch (t) by month

Source: Statistics Iceland, weight reports

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Greenland shark catch (t) by fishing gear

                                       Source: Statistics Iceland, weight reports

Scientific: Somniosus microcephalus. English: Greenland shark. Icelandic: Hßkarl. For more languages see the marine animal dictionary.

Biology and distribution

The Greenland shark is the most cold tolerant shark (or dogfish) species in the world, and the only one that is native to the cold waters north of Iceland. It occurs in the entire northern North Atlantic, but specimens have also been reported in waters off the Azores and even off South Africa. A closely related species (Somniosus pacificus) is in the northern Pacific. The Greenland shark occurs all around Iceland but is more common in the north.

The shark can get quite large, or up to 7 meters long, and possibly even longer. Usual size is 2 to 5 m. The Greenland shark is a voracious eater of everything that is smaller than itself, both live prey and carrion. Among the things that have been found in a Greenland shark stomach are all possible fishes, seals, porpoises, dolphins, seabirds, reindeer, horses, cats and dogs. The last four were probably already dead when eaten.

The Greenland shark has live pups that are already about 40 cm long when born. It is difficult to age determine the Greenland shark, but tagging studies suggest that it grows very slowly and presumably reaches a very old age.

Catch and fishing methods

Greenland shark fisheries have probably been conducted in Icelandic waters from the time of settlement. They reached a large scale in the 18th century, and a zenith in 1867 when 13,100 barrels of shark oil were exported (each barrel is about 62 l). This was probably the most important marine resource in Icelandic waters at the time, and these were the only fisheries by Icelanders prior to the 20th century that can be described as deep-water fisheries. Despite this, they were first conducted in open rowing boats, but later they were the first Icelandic fisheries to use decked sailing boats extensively. Usually only the liver was retained, yielding valuable oil used for lighting up cities in Europe. When whale oil and fuel oil became more available the markets for the shark oil disappeared and direct fisheries for the Greenland shark were over by about 1910. Catches have been low since that time, or about 40 tonnes annually, mostly bycatch in bottom trawls but a few are caught each year in direct longline fisheries. Most of the catches are during spring and early summer.

Stock status

No information is available on the stock status of this species.

Processing and markets

This is the only Icelandic fish species where the majority, if not all of the catches go to local consumption. It is considered lightly poisonous when fresh, but Icelanders have a way to wind dry it and cure it and get rid of the poison. After curing, it has a strong ammonia taste that is not loved by everyone.

References and further information

  • Jˇnsson, G., & Pßlsson, J. (2006). ═slenskir fiskar (Icelandic fishes). ReykjavÝk, Iceland. 336 p (in Icelandic)
  • Yano, K., Stevens, J. D., & Compagno, L. J. (2007). Distribution, reproduction and feeding of the Greenland shark Somniosus (Somniosus) microcephalus, with notes on two other sleeper sharks, Somniosus (Somniosus) pacificus and Somniosus (Somniosus) antarcticus. Journal of Fish Biology 70, 374-390

Hrei­ar ١r Valtřsson, University of Akureyri

 

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