Spotted Seal - Phoca largha

Taxonomy & Nomenclature

Scientific Name Phoca largha
Author Pallas, 1811
Taxonomic Rank Species
Taxonomic # 180642
Common Names English: Spotted Seal
Current Standing valid
Taxonomic Parents Kingdom: Animalia
  Phylum: Chordata
    Subphylum: Vertebrata
      Class: Mammalia
        Subclass: Theria
          Infraclass: Eutheria
            Order: Carnivora
              Suborder: Caniformia
                Family: Phocidae
                  Genus: Phoca
Taxonomic Children
Synonyms (since 1950)
Taxonomic data is courtesy of the Integrated Taxonomic Information System (ITIS)
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Physical Description / Field Identification

The spotted seal is a sibling species with the harbor seal. Their coloration is generally pale, silver gray above and below, with a darker mantle dominated by even darker oval spots of fairly uniform size (1-2 cm) and generally oriented parallel to the long axis of the body. There may be light rings around some spots, or large irregular spots or blotches. Spotting tends to be of fairly even distribution and darkness overall. In harbor seals, spots are more faded and sparse on the underside. The face and muzzle are darker. Pups are born with a long and woolly whitish lanugo, which is shed 2-4 weeks after birth.

The dental formula of adults is I 3/2, C1/1, PC 5/5.

Adult males are up to 1.7 m and females to 1.6 m long. Adults weigh 82-123 kg. At birth, spotted seals are 77-92 cm long and weigh 7-12 kg.

Can be Confused With

In addition to harbor seals, spotted seals share their range with ringed and ribbon seals. Ribbon seals lack spots and have broad bands on a black or brown body, or as juveniles are dull gray above and lighter below, but in all age classes and both sexes ribbon seals lack the abundant spots of the spotted seal.

The range of the eastern Pacific and Western Pacific subspecies of the harbor seal overlaps with the range of the spotted seal. Unfortunately, the consistent differences between the species are features of the skull and genetic characteristics. Coloration, body size and shape, and size of features overlap in the two species. Some of the best features are behavioral. Spotted seals give birth on sea ice and usually are alone or accompanied by a male. Harbor seals give birth in haul-out groups typical of the sites where they are found year-round. In addition to being born in a long gray lanugo coat, spotted seals spend their first weeks on the ice, while harbor seals are generally born in a short hair coat similar to the adult, and are able to swim within hours of birth. Where they co-occur, spotted seals give birth up to 2 months earlier than harbor seals.

Spotted seals and ringed seals can be easily confused. Spotted seals are longer and proportionately leaner, with a longer neck, head, and muzzle. Spotted seals rarely have many rings, whereas ringed seals have an abundance of rings and a low density of less conspicuous spots. Pups of both species are born in a long, grayish lanugo coat and would be difficult to tell apart if away from adults. However, spotted seal pups are born on top of ice floes, whereas ringed seal pups are born in lairs under snow and ice.

Spotted seals haul-out on land, and can be found mixed in with groups of harbor seals in at least Bristol Bay, Alaska, and are said to be separable from harbor seals only by experienced observers based on behavior, response to disturbance, and subtle differences in facial features.

Distribution

Spotted seals are widespread in the Sea of Okhotsk and the Sea of Japan, and reach China in the northern Yellow Sea. They are widespread in the Bering and Chukchi Seas and range north into the Arctic Ocean north to about the edge of the continental shelf, west to about 170°E and east to the Mackenzie River Delta in Canada. They inhabit the southern edges of the pack ice from winter to early summer. In late summer and fall, ringed seals move into coastal areas, including river mouths. They breed exclusively, and haul-out regularly, on sea ice, but do come ashore on beaches and sandbars.

Ecology and Behavior

Spotted seals are widespread in the Sea of Okhotsk and the Sea of Japan, and reach China in the northern Yellow Sea. They are widespread in the Bering and Chukchi Seas and range north into the Arctic Ocean north to about the edge of the continental shelf, west to about 170°E and east to the Mackenzie River Delta in Canada. They inhabit the southern edges of the pack ice from winter to early summer. In late summer and fall, ringed seals move into coastal areas, including river mouths. They breed exclusively, and haul-out regularly, on sea ice, but do come ashore on beaches and sandbars.

Feeding and Prey

Adults can dive to at least 300 m, and feed on a wide variety of organisms; composition of diet varies with the age of the seal, and on seasonal variation in abundance of preferred prey species. Newly weaned pups feed on small crustaceans, advance to schooling fishes, larger crustaceans, and octopuses, and finally graduate to higher percentages of bottom dwelling fish species.

Threats and Status

Subsistence hunting of spotted seals has no doubt occurred since humans made first contact with the species. Intensive harvesting of commercial fish species in the North Pacific and southern Bering Sea poses an as-yet unquantified risk. Entanglement in commercial fisheries occurs in Japan and the Sea of Okhotsk, and fisheries damage control kills regularly occur in small numbers in Japan.

Global climatic change, including global warming, and decreases in annual sea ice development and extent of coverage pose an unknown, but potentially serious, threat to this pagophillic species.

Links

References

Burns, J.J. 2002. Harbor seal and spotted seal Phoca vitulina and P. largha. pp. 552-560 in W.F. Perrin, B. Würsig and J.G.M. Thiewissen, eds. Encyclopedia of Marine Mammals. Academic Press.

King, J.E. 1983. Seals of the world. Second Edition. British Museum (Natural History), Comstock Publishing Associates, and Cornell University Press. 240 pp.

Lowry, L.F., K.J. Frost, R. Davis, D.P. Demaster and R.S. Suydam. 1998. Movements and behavior of satellite-tagged spotted seals (Phoca largha) in the Bering and Chukchi seas. Polar Biology 19:221-230.

Lowry, L.F., V.N. Burkanov, K.J. Frost, M.A. Simpkins, R. Davis, D.P. Demaster, R. Suydam and A. Springer. 2000. Habitat use and habitat selection by spotted seals (Phoca largha) in the Bering Sea. Canadian Journal of Zoology 78:1959-1971.

Mizuno, A.W., M. Suzuki and N. Ohtaishi. 2001. Distribution of the spotted seal Phoca largha along the coast of Hokkaido, Japan. Mammal Study 26:109-118.

ITIS TSN180642
Status - ESA, U.S. FWS -
    T (Southern)
Status - Red List, IUCN -
    LC (Global or one of the sub regions)
#records (spatial)116
#records (non-spatial)0
#datasets3
Year1981 - 2013
Latitude59.70 - 73.65
Longitude-168.88 - -138.66
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