Spotted seal (Phoca largha)

Description

What’s the World’s Favourite Species?

Spotted seal fact file

• Description
• Biology
• Range
• Habitat
• Status
• Threats
• Conservation
• Find out more
• Glossary
• References
• Print factsheet

Spotted seal description

The spotted seal (Phoca largha) varies in colouration from very light to very dark ⁽⁵⁾, but is generally pale on the underside, with darker silver or grey over the rest of the body ^{(2) (3) (4) (6) (7)}. Brown colouration also sometimes occurs ⁽⁶⁾. As its name suggests, the spotted seal is marked with a pattern of dark spots, which measure about one to two centimetres in diameter and are evenly distributed along the body ^{(4) (6)}. Some spots may be surrounded by a light ring, or there may be large, irregularly-shaped spots or blotches ⁽⁴⁾.

This species has a rounded head, a narrow snout, and short, narrow flippers ⁽⁸⁾. There are few differences in size and appearance between the male and female spotted seal ⁽⁸⁾, but pups are born with a white, fluffy coat, or ‘lanugo’, which is usually shed about two to four weeks later ^{(3) (4) (6) (7)}.

Until fairly recently, the spotted seal was considered to be a subspecies of the closely related common or harbour seal, Phoca vitulina ⁽⁴⁾. The two species are very similar in appearance, but the spots of the harbour seal tend to appear more faded and are sparser on the underside of the body. The spotted seal is generally slightly smaller than the harbour seal and has a darker face and muzzle, and there are also behavioural differences between the two species ⁽⁴⁾.

Also known as

larga seal.

Synonyms

Phoca vitulina largha.

Size

Male length: 150 - 170 cm ^{(2) (3)}

Female length: 140 - 160 cm ^{(2) (3)}

Newborn length: 77 - 92 cm ⁽⁴⁾

Male weight: 85 - 110 kg ⁽²⁾

Female weight: 65 - 115 kg ⁽²⁾

Newborn weight: 7 - 12 kg ^{(2) (4)}

Spotted seal biology

The spotted seal begins to breed from three to four years old in females and four to five years old in males ^{(1) (2) (5) (7)}. Most births occur between January and mid-April, usually with a peak around mid-March ^{(2) (4) (6) (8) (9)}. The female spotted seal gives birth to a single pup each year ⁽¹⁾, after a gestation period of just over ten months ⁽⁸⁾.

Male spotted seals are less aggressive towards females than in some other seal species ⁽⁵⁾, and are thought to be monogamous ^{(1) (3) (4) (5) (8)}. During the breeding season, a male spotted seal will join a female about ten days before the female gives birth, and will then defend the female and pup on the ice floe ^{(1) (3) (7)}. The male will mate with the female after the pup has been born ^{(1) (7)}.

Although the spotted seal pup spends the first few weeks of its life on ice, it is able to swim within hours of being born ⁽⁶⁾. Weaning takes place at around four to six weeks old ^{(2) (3) (7) (8)}. Newly weaned pups can only dive to depths of around 80 metres, feeding mainly on small crustaceans, but adult spotted seals can dive to 300 metres or more, and feed on a wide variety of fish, squid and crustaceans ^{(3) (4) (7) (8) (9)}.

The spotted seal has a potential lifespan of 35 years ^{(2) (7) (8)}, but few individuals have been known to live for more than 25 years, with around 45 percent dying within their first year ⁽⁹⁾. Predators of the spotted seal include Pacific sleeper sharks (Somniosus pacificus), orcas (Orcinus orca), polar bears (Ursus maritimus), brown bears (Ursus arctos), Arctic foxes (Vulpes lagopus) and various predatory birds ^{(1) (7) (9)}.

Spotted seal range

The spotted seal is found around the North Pacific Ocean, from the coast of Alaska, through the Bering Sea, to the Sea of Okhotsk, Sea of Japan, Yellow Sea and Bohai Sea ^{(1) (4) (7) (8)}. This species also ranges as far north as the Arctic Ocean, west to about 170 degrees East, and east to the Mackenzie River Delta in Canada ^{(1) (6)}.

Spotted seal habitat

A species of Arctic and sub-Arctic waters ⁽⁸⁾, the spotted seal inhabits the southern edges of the pack ice from winter to early summer, and moves into coastal areas, including river mouths, during late summer and autumn ^{(1) (2) (3) (4) (6) (7)}.

Although it usually breeds and hauls out on ice, the spotted seal has also been known to come ashore on beaches and sand bars ^{(1) (4)}. At some sites along the Asian coast, this species breeds on small, remote islands ⁽¹⁾.

Spotted seal status

The spotted seal is classified as Data Deficient (DD) on the IUCN Red List ⁽¹⁾.

Spotted seal threats

Hunting of the spotted seal is known to occur, but does not seem to have had a dramatic effect on its population size. However, commercial harvesting of fish currently poses a risk to this species due to competition between spotted seals and fisheries for prey species ^{(1) (6) (7) (9)}. As with other marine species, entanglements and injuries due to fishing gear also occur, especially off the coasts of Japan and in the Sea of Okhotsk ^{(1) (6)}. In some areas, fishermen shoot small numbers of spotted seals, and small organised kills also occur to limit damage to fisheries ^{(1) (7)}.

Adverse environmental conditions have been known to injure or kill spotted seals, mainly pups that have become caught between sheets of colliding pack ice ⁽⁹⁾. A newer, potentially greater risk to the spotted seal comes from oil and gas exploration and extraction. This could destroy the spotted seal’s habitat, as well as causing direct disturbance to the seals and the risk of pollution and oil spills ^{(1) (7)}.

Perhaps of greatest concern for the spotted seal is a predicted reduction in sea ice as a result of climate change ^{(1) (7) (10)}. As well as affecting the location, timing and stability of the ice, changes to the climate and ocean could also affect the availability of the spotted seal’s prey ⁽¹⁾. Although the two main northern populations of the spotted seal are not currently considered to be at risk of extinction due to changes in sea ice, a smaller, more southerly population off the coasts of China and Russia has been assessed by the National Oceanic and Atmospheric Administration (NOAA) as being threatened ^{(8) (10)}.

Spotted seal conservation

There is currently a ‘total allowed catch’ policy in place in some areas to control hunting of the spotted seal ⁽⁹⁾. In the United States, the spotted seal is protected from hunting, other than subsistence hunting by Alaska Natives, by the Marine Mammal Protection Act of 1972. This prohibits the import and export of this species or its products ^{(1) (8)}.

Commercial hunting of the spotting seal in Russia ended in 1994, but a small-scale harvest still occurs in some areas ⁽¹⁾. The spotted seal is listed as a nationally endangered animal in China, and it has been suggested that the Dalian Seal Sanctuary, a nature reserve in the Bohai Sea, should be upgraded to national status ⁽⁷⁾.

Although the spotted seal is still relatively abundant and widespread, there are no reliable estimates of its global population size or of the extent of any population declines, making it difficult to accurately assess the species’ current conservation status ⁽¹⁾.

Find out more

Find out more about the spotted seal and its conservation:

• Seal Conservation Society - Spotted seal (Phoca largha):
  http://www.pinnipeds.org/seal-information/species-information-pages/the-phocid-seals/spotted-seal
• Jefferson, T.A., Leatherwood, S. and Webber, M.A. (1993) FAO Species Identification Guide. Marine Mammals of the World. FAO, Rome. Available at:
  http://nlbif.eti.uva.nl/bis/marine_mammals.php?menuentry=inleiding
• NOAA Fisheries: Office of Protected Resources - Spotted seal (Phoca largha):
  http://www.nmfs.noaa.gov/pr/species/mammals/pinnipeds/spottedseal.htm

Find out more about climate change at ARKive’s climate change pages:

• ARKive - Climate change:
  http://www.arkive.org/climate-change/

Authentication

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
arkive@wildscreen.org.uk

This species information was authored as part of the ARKive and Universities Scheme.

Glossary

Crustaceans

Diverse group of animals with jointed limbs and a hard chitinous exoskeleton, characterised by the possession of two pairs of antennae, one pair of mandibles (mouthparts used for handling and processing food) and two pairs of maxillae (appendages used in eating, which are located behind the mandibles). Includes crabs, lobsters, shrimps, woodlice and barnacles.

Gestation

The state of being pregnant; the period from conception to birth.

Monogamous

Having only one mate during a breeding season, or throughout the breeding life of a pair.

Pack ice

Sea ice that floats on the surface of the water. Often formed from large pieces of ice that consolidate into a single ice mass, pack ice typically moves with currents, tides and wind.

Subspecies

A population usually restricted to a geographical area that differs from other populations of the same species, but not to the extent of being classified as a separate species.

References

1. IUCN Red List (April, 2012)
   http://www.iucnredlist.org/
2. Macdonald, D.W. (2006) The Encyclopedia of Mammals. Oxford University Press, Oxford.
3. Nowak, R.M. (1991) Walker’s Mammals of the World. The Johns Hopkins University Press, Baltimore and London.
4. Jefferson, T.A., Leatherwood, S. and Webber, M.A. (1993) FAO Species Identification Guide. Marine Mammals of the World. FAO, Rome. Available at:
   http://nlbif.eti.uva.nl/bis/marine_mammals.php?menuentry=inleiding
5. Archer, G. (1995) Aquatic Mammals Illustrated. Navigator Books, Ringwood.
6. Jefferson, T.A., Webber, M.A. and Pitman, R.L. (2008) Marine Mammals of the World: A Comprehensive Guide to their Identification. Academic Press, London.
7. Seal Conservation Society - Spotted seal (Phoca largha) (April, 2012)
   http://www.pinnipeds.org/seal-information/species-information-pages/the-phocid-seals/spotted-seal
8. NOAA Fisheries: Office of Protected Resources - Spotted seal (Phoca largha) (March, 2012)
   http://www.nmfs.noaa.gov/pr/species/mammals/pinnipeds/spottedseal.htm
9. Wilson, D.E. and Ruff, S. (Eds.) (1999) The Smithsonian Book of North American Mammals. Smithsonian Institution Press, Washington.
10. National Oceanic and Atmospheric Administration (NOAA) (2009) NOAA will not list two spotted seal populations as endangered or threatened. NOAA, 15 October. Available at:
    http://www.noaanews.noaa.gov/stories2009/20091015_spottedseal.html