Biodiversity & Conservation

Common or Harbour seal - Phoca vitulina

Phoca vitulina

Image Sue Scott - Common seal on rock. Image width ca XX cm.
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Distribution map

Phoca vitulina recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)

Why do the maps differ?

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  • EC_Habitats
  • NI_Act
  • UK_BAP
Taxonomy icon Taxonomy Taxon English term
Phylum Chordata Sea squirts, fish, reptiles, birds and mammals
Class Mammalia Seals, walrus, dolphin and whales
Authority Linnaeus, 1758
Recent synonyms None
Map icon Recorded Distribution in Britain and Ireland The species is fairly evenly distributed around the coasts of Great Britain and Ireland, except for regions where there are extensive cliffs (Hewer, 1974). It is most commonly seen on the east coast of England, western Scotland and the northern isles.
Habitat information icon Habitat information The common seal lives mainly along shorelines and in estuaries. It is commonly seen resting on sandbanks, easily accessible beaches, reefs and protected tidal rocks.
Text page icon Description Common seals have a rounded head with eyes equidistant between the nose and the ears. The nostril slits form a characteristic 'v' shape when viewed from the front. Adult common seals grow up to 1.2 to 2 metres long, and weigh around 65-140 kg. Males are slightly bigger than females. The coat is grey to brownish-grey with a uniform pattern of small darker spots, although the pattern varies geographically. Individuals may live for 20-30 years (SMRU, 2004).
Identifying features
  • Lacking external ear flaps.
  • Colouration variable but generally coat is grey or brownish grey with small spots.
  • Head rounded with nostrils forming 'v' shape when animal viewed head on.
  • Eyes equidistant between ear and nose.
  • 3 front teeth, one eye tooth and 5 cheek teeth in each half of upper jaw.
  • 2 front teeth, one eye tooth and 5 cheek teeth in each half of lower jaw.
Additional information icon Additional information May be confused with the grey seal (Halichoerus grypus) that has a much longer muzzle and their nostril slits are nearly parallel.

Seals are highly adapted to live in water. Their limbs are modified into flippers and they have streamlined bodies. Phoca vitulina can dive to 450 m and remain submerged for up to 30 minutes. The common seal is a strong swimmer and can be seen leaping completely out of the water (porpoising) (Nowak, 2003). Only the head is usually seen when the seal is in water. As well as being fur-coated they have a thick layer of subcutaneous fat or blubber. This keeps them warm and enhances streamlining (SMRU, 2004). Seals are warm-blooded air-breathing mammals but spend a considerable amount of time below the water surface. Common seals give birth to pups in June and July and moult in August. The main threat to seals in the UK and Ireland is organochlorine compounds that may interfere with reproduction (SMRU, 2004).

The Common or harbour seal has been reported as non-migratory and littoral in distribution and as exhibiting a diurnal haul-out pattern (Evans & Raga, 2001). Common seals in Europe belong to a distinct sub-species. Britain holds around 40% of the world population of the European sub-species (Duck & Thompson, 2003).

The Conservation of Seals Act, 1970, provides a closed season for the Common seal during its pupping season. During this time, it is illegal to kill or take seals without a licence. There is also provision for giving complete protection to seals at al times, if neccesary. During the close season, a license is required to handle seals unless they are sick or injured (SMRU, 2004). The Baltic and Wadden Sea populations are listed under the Bonn Convention (Appendix II).

This review can be cited as follows:

Judith Oakley 2008. Phoca vitulina. Common or Harbour seal. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 31/07/2010]. Available from: <http://www.marlin.ac.uk/speciesinformation.php?speciesID=4097>