The Spotted Seal (Phoca largha) is an abundant species found in the Arctic and subarctic North Pacific Ocean, and named for obvious reasons. They are closely related to the Harbour Seal (Phoca vitulina), but separated morphologically and behaviourally. The word ‘largha’ comes from the original name given to the seals by the native Siberian people. The species is described as Least Concern by the IUCN. Estimated population size = 643,300.
P. largha are true seals that are medium in size (males ♂ up to 1.7 m long/ 123 kg, females ♀ up to 1.6 m/ 110 kg), usually slightly smaller than P. vitulina. With short, backward-facing hind flippers and short front flippers with long claws,the seals are plump in shape, with rounded heads and muzzles and large, dark eyes. Generally, overall colour of the coat is pale grey or silvery, but the head and back may be darker. The diagnostic spots are black and uniform across the coat, appearing in different sizes, and in a mixture of spots and splodges.
P. largha are generalist predators that will feed on whatever is available locally and seasonally. Animals incorporated into this diet include: pollock, cod, rockfish, herring, smelt, capelin, salmon, flatfish, squid, octopus, shrimp and crab. Younger individuals may mostly rely on krill for their nutritional needs. Dives of around 300 m are often undertaken to forage in the open ocean.
Sexual maturity – males ♂ 4-5 years old/ females ♀ 3-5 years old.
P. largha are a shy and solitary species which gathers in large aggregations on ice or land during the breeding season (January – April). They form family units or ‘triads’ consisting of the male, female and pup, and are thought to be seasonally monogamous. Mating likely occurs in water, and after a 10 month gestation, a small pup with a fluffy white lanugo coat is born. Most births occur towards the latter part of the breeding season, as the region comes into spring. Weaning age varies with region and may be as short as 2-3 weeks in Japan, but more like 4-6 weeks elsewhere. Around this time they will lose their newborn coat too. Time is taken learning to dive and forage effectively after this, however they are capable of swimming if necessary. Adult moults occur during May-June. Life expectancy in P. largha is thought to routinely be up to a maximum of 35 years.
In the past, P. largha was classified as a subspecies of P. vitulina. However it was more recently given species status of its own, and there are not currently known to be any subspecies.