(Pallas, 1811) - Larga seal
Distinctive Characteristics
Until recently, Larga seals were considered a subspecies of the harbour seal. Studies revealed morphological, biochemical, and behavioural differences sufficient to warrant its reclassification as a full species. Larga seals are smaller than harbour seals, but are nearly identical in build and proportions.
Coloration is generally pale, silver-grey above and below, with a darker mantle dominated by dark oval spots of fairly uniform size (1 to 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 harbour seals, spots are more faded and sparse on the underside. The face and muzzle are darker than in the harbour seal. Pups are born with a long, woolly, whitish lanugo, which is shed 2 to 4 weeks after birth.
The dental formula of adults is I 3/2, C 1/1, PC 5/5.
Can be confused with
In addition to harbour seals, 2 other phocids (ringed and ribbon seals) share the the Larga seal's range. Details of pelage markings and coloration, particularly the presence or absence of large numbers of rings (ringed seals), or conspicuous light and dark bands (ribbon seals) are sufficient to distinguish among them. Further, ringed seals are generally solitary beside breathing holes, while Larga and ringed seals are most often found along fractures in larger floes. Of these species, only the ribbon seal moves on ice or land by slashing motion; the others inch along.
Size
Adult males are up to 1.7 m and females to 1.6 m long. Adults weigh 82 to 123 kg. At birth, Larga seals are 77 to 92 cm long and weigh 7 to 12 kg.
Geographical Distribution
Larga seals are widespread in the Sea of Okhotsk, and Yellow, Japan, and Bering seas. They inhabit the southern edges of the pack ice from winter to early summer and coastal areas, including river mouths, in late summer and autumn. They breed exclusively, and haul out regularly, on ice, but do come ashore on beaches and sand-bars.
Biology and Behaviour
Larga seals are annually monogamous and territorial. Breeding takes place on pack ice from January to mid-April. Pupping peaks from mid to late March.
Adults can dive to at least 300 m, and they feed on a wide variety of organisms; composition of diet varies with the age of the seal. Newly weaned pups feed on small crustaceans, advance to schooling fishes, larger crustaceans, and octopuses, and finally graduate to bottom dwelling fish and cephalopods.
Exploitation
Small commercial and subsistence harvests of Larga seals have been active throughout this century, and continue to this day. An unknown number are incidentally caught in drift and gill net fishing operations every year.
IUCN Status
Insufficiently known.