Seals

Seals

5-Seals-(D)-Harbour_seal--(copyright-Jon_B_H)

Harbour seal                 

Illustration: Jón Baldur Hlíđberg

5-Seals-(D)-Grey_seal--(copyright-Jon_B_H)

Grey seal                                           

Illustration: Jón Baldur Hlíđberg

Only 2 species of seals are native to Iceland, grey seals (Halichoerus grypus) and common or harbour seals (Phoca vitulina). Greenland or harp seals (Phagophilus groenlandicus), ringed seals (Phoca hispida), and hooded seals (Cystophora cristata) are frequent guests in the winter, while bearded seals (Erignathus barbatus) and walruses (Odobenus rosmarus) are rarer.

Resident seals

The harbour, or common, seal is the most abundant seal around Iceland. It can be found all around the country but is rarer in the northern part. They are coastal, non- migratory, and aggregate in small numbers on skerries, small islands, and also on beaches and in estuaries. This is a rather small seal and can reach a maximum of 2 m in length. The average size of males is 1.7 m and 105 kg. The females are smaller as is almost universal for seals. It breeds in the spring. They eat a variety of fish species, cephalopods and crustaceans.

The grey seal is larger than the harbour seal; they can reach up to 3 m in length and 300 kg in weight. This species can also be found all around Iceland, but is even rarer than the harbour seal in the colder waters off the northeast and east coast. Both species of resident seals are classified as coastal seals, i.e. they are not known to leave the Icelandic shelf. However, the grey seal is shyer than the harbour seal and therefore less often seen. This is reflected in the Icelandic name for these species, grey seal is “útselur” or outer-seal and harbour seal is “landselur” or land-seal. As opposed to the harbour seal, the grey seal breeds in autumn. The diet of the grey seal is mostly fishes. Similar as with the hooded seals, the grey seals are not popular with fishermen because they bite fish in nets to eat the liver. This seal is also one of the main hosts for a roundworm that infects fish.

Vagrant seals

5-Seals-(P)-Bearded_seal--(copyright-Skapti_H)

Bearded seal

Photo: Skapti Hallgrímsson

Walruses and bearded seals have similar habits as they both feed mostly on benthic animals and are therefore most common in shallow waters in the Arctic. Nevertheless, both species can swim considerable distances offshore and consequently may be seen occasionally in Icelandic waters. Walruses have even reached the North Sea.

Ringed seals are the classic Arctic ice seals since they can maintain breathing holes in thick sea ice far away from the ice edge, something the other species cannot do. This is, therefore, the most abundant seal species in the Arctic and also the main prey of the polar bear. The species is common around Iceland in cold ice-years. In some areas in Northern Iceland, such as in Eyjafjörđur, it can be seen almost every winter.

Hooded seals are large seals that breed on the pack ice. The rest of the year they mostly live offshore all over the North Atlantic. They are not uncommon in northern Icelandic waters, especially in winter. They are considered a pest by inshore fishermen as they kill fish that is stuck on longlines or in gillnets. The seals do not eat the entire fish, only the liver. They have even been known to enter bottom trawls to feed on the fish. Satellite tags reveal that hooded seals swim all around Iceland, even all the way to northern Scotland.

The above mentioned species are usually found as individuals. Harp seals, however, are highly gregarious. They migrate long distances and were sometimes quite a frequent sight in Icelandic waters when the drift ice was close by. In such times of hardship, harp seals were often hunted, being ready prey when other food was scarce. Harp seals do not have the same bad reputation as hooded seals, as they mainly prey on pelagic crustaceans and small fishes and do not compete as much with fishermen.

Stock sizes and exploitation

5-seals-(g)-numbers-(hafro) 

The estimated number of resident seals around Iceland

Source: The Marine Research Institute

5-seals-(g)-seals-total-catch-(statice-&-ices)

Seal catch in Iceland

Source: The Marine Research Institute

The numbers of seals breeding in Iceland are actually small compared to the hundreds of thousands of the Arctic seals breeding on the pack ice. A grey seal survey was conducted in 2005 from which 6,000 grey seals were estimated along the Icelandic coast. The stock was estimated at 12,000 in 1990. According to a survey conducted in August 2006, the stock of common seals was in the region of 12,000 animals. That stock was estimated at approximately 30,000 individuals in 1980.

Sealing has never reached industrial proportions in Iceland; stock sizes do not allow that. Seal hunting, nevertheless, used to be important for the small local population in Iceland as seals yield oil and meat for domestic use and fur for domestic use and export. It was therefore considered a great benefit to have a seal rockery on one’s land. Although many rockeries were probably exterminated in the first centuries of settlement, they were managed by the landowners later on, so the hunting of the valuable pups could continue.

Between 6,000 and 7,000 seals were hunted annually at the beginning of the 20th century. The value of the seal products did, however, decline compared to other products so catches fell to about 2,000 animals annually in 1960. Because of a fashion trend for seal furs, catches increased after that to about 6,000 animals a year, mainly harbour seal pups. The anti-sealing campaign caused prizes and catches to collapse after 1975.

Catches increased again due to a bounty system in 1982. This aimed at lowering the seal numbers to reduce ringworm infection in fish as the seals are an important host for the worm. However, catches have declined again. In 2007, the reported seal catch in Iceland was 274 grey seals, 104 common seals, and 1 of each of harp, ringed and bearded seals.

References and further information

  • Hauksson, E. (2004a). Vöđuselur (Harp seal). In Hersteinsson, P. (ed.), Íslensk spendýr (Icelandic mammals) (pp. 124-127). Reykjavík, Iceland: Helgafell.
  • Hauksson, E. (2004b). Hringanóri (Ringed seal). In Hersteinsson, P. (ed.), Íslensk spendýr (Icelandic mammals) (pp. 128-131). Reykjavík, Iceland: Helgafell.
  • Hauksson, E. (2004c). Kampselur (Bearded seal). In Hersteinsson, P. (ed.), Íslensk spendýr (Icelandic mammals) (pp. 144-145). Reykjavík, Iceland: Helgafell.
  • Hauksson, E., & Ólafsdóttir, D. (2004). Útselur (Grey seal). In Hersteinsson, P. (ed.), Íslensk spendýr (Icelandic mammals) (pp. 132-139). Reykjavík, Iceland: Helgafell.
  • Hauksson, E., Bogason, V., & Ólafsdóttir, D. (2004). Landselur (Harbor seal). In Hersteinsson, P. (ed.), Íslensk spendýr (Icelandic mammals) (pp. 116-123). Reykjavík, Iceland: Helgafell.
  • Ţórđarson, G. (2004). Blöđruselur (Hooded seal). In Hersteinsson, P. (ed.), Íslensk spendýr (Icelandic mammals) (pp. 140-143). Reykjavík, Iceland: Helgafell.
  • Ţórđarson, G., & Hauksson, E. (2004). Rostungur (Walrus). In Hersteinsson, P. (ed.), Íslensk spendýr (Icelandic mammals) (pp. 112-115). Reykjavík, Iceland: Helgafell.

Hreiđar Ţór Valtýsson, University of Akureyri

 

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