Bearded seal (Erignathus barbatus)
Bearded seals are the largest of the northern phocid seals. They have an extremely elaborate, long set of whiskers that tend to curl when they are dry. It is these whiskers (or vibrissae) that give the species its name.
Bearded seals are the largest of the northern phocid seals. Adults are 2–2.5 meters long and are grey-brown in colour (some individuals have irregular light-coloured patches). The weight of bearded seals varies dramatically on an annual cycle, but an average weight is 250–300 kg. Females, which are somewhat larger than males in this species, can weigh in excess of 425 kg in the spring. The sexes are not easily distinguished. Bearded seals have several distinctive physical features: their bodies have a very rectangular shape; their heads appear to be small compared to the size of their bodies; they have square-shaped front flippers with the longest toe being the middle one, and very strong claws; and they have an extremely elaborate, long set of whiskers that tend to curl when they are dry. It is these whiskers (or vibrissae) that give the species its name. Pups are approximately 1.3 meters long at birth and weigh an average of 33 kg. At birth they have a partial coat of fuzzy grey-blue fur, but have already commenced moulting into a smooth dark-grey coat, with a light belly, that is their pelt by the time they are a few weeks old. Their faces have white cheek patches and white eyebrow spots that give them a ”bandit” or ”teddy-bear” appearance. Yearlings look very similar to pups, but the facial patterns are somewhat less distinct and they often have dark spots on their bellies.
Bearded seals have a patchy distribution throughout the circumpolar Arctic. Their preferred habitat is drifting pack ice in areas over shallow water shelves. Juvenile animals wander quite broadly, but adult animals tend to have quite small home ranges, remaining in coastal waters much of the year. Bearded seals are found at low densities in all of Svalbard’s fjords on a year-round basis, and in coastal regions wherever there is drifting ice.
It is not possible to provide accurate abundance estimates for bearded seals because they are very difficult to survey. But, this species probably numbers in the hundreds of thousands globally and there are thousands of bearded seals in the Svalbard area. Similar to ringed seals, bearded seals are ice-loving seals. It is unusual to see a bearded seal on land; they prefer to haul out on ice. But, bearded seals do come ashore to rest occasionally in Svalbard during the summer months. This seal species is very calm and it can be approached easily in areas where they are not routinely hunted.
Bearded seals shed their hair much more diffusely than other phocid seals, losing some hair most of the year. But, they do have a concentrated period of moulting in June/July when they prefer not to go into the water. At this time of year there is not a lot of ice available in coastal areas, so bearded seals can be seen in small groups on the available ice. Beyond the loose social aggregations that occur during breeding and moulting, bearded seals are for the most-part solitary animals.
Bearded seals are not deep divers; they feed in shallow coastal areas and hence normally are not required to dive to depths of more than 200–300 metres. Pups dive to much greater depths during their first year (up to 450 m), but older, more experienced animals remain in shallow water where most of their benthic prey resides.
Bearded seals eat a wide variety of different types of prey, but they are predominantly benthic feeders, eating clams, shrimps, crabs, squid, fishes and a variety of other small prey that they find near, on, or in the ocean floor. They can search soft bottom sediments using their whiskers to find hidden prey that they get at using a combination of water jetting and suction. Some bearded seals in Svalbard have rust-coloured faces and foreflippers. This colouration is the result of iron-compounds from soft-bottom substrates sticking to the hairs while the animals feed and then chemically reacting with oxygen when brought to the surface. The rust is on the hairs rather than in them.
Life history and reproduction
Bearded seals give birth in the spring. In Svalbard, the peak pupping period is early May. Females normally give birth on small, drifting ice floes in shallow areas. The pups enter the water very quickly, only hours after birth, which is likely a response to heavy predation by polar bears. The pups become proficient divers during the 18–24 days they are cared for by their mothers. During this time they consume about eight litres of milk per day that has a 50% fat content. Consequently, they grow rapidly during this time – at an average rate of 3.3 kg per day. Pups usually weigh about 100 kg when they are weaned. Mating takes place toward the end of the lactation period. During the breeding period male bearded seals ”sing” to attract females. Their beautiful, but slightly melancholy, underwater songs are composed of a downward spiralling trill that can be heard for many kilometres in calm conditions. Males defend small patches of ocean with elaborate bubble displays, where they sing their songs intensively and repeatedly over a period of some weeks. Individual males occupy the same areas from one year to the next for at least several years. Female bearded seals reach sexual maturity when they are about five years old, whereas males are a bit older, usually six or seven when they reach maturity. Bearded seals normally live to an age of 20–25 years.
Management status and monitoring
Bearded seals are an important subsistence resource for coastal peoples throughout much of theArctic.Russiahad a commercial harvest of this species in theSeaofOkhotskand theBering Seawith annual catches that exceeded 10,000 animals in some years during the 1950s and 1960s. Quotas were established to reduce hunting and catches dropped to a few thousand bearded seals annually in the 1970s and 1980s in these regions. Norwegian sealers and whalers also killed significant numbers of bearded seals as a by-catch when in northern waters targeting whales or polar bears. In Svalbard, it is legal for licensed hunters to harvest bearded seals outside the breeding season (at which time they are protected) and some 10s are shot annually. Bearded seals, like all other species, are totally protected in the national parks and nature reserves in Svalbard throughout the year. In recent years in Svalbard there have been spring seasons during which sea ice did not form in traditionally used pupping areas in the fjords on the west coast of Spitsbergen. Bearded seals have managed to raise their young in these conditions, by using glacier ice pieces as a substrate to give birth and nurse their young. Young bearded seals are strong enough to climb up onto these irregular pieces of ice, although the flat annually-formed sea ice is clearly a preferred habitat. This refuge within a warming Arctic will likely be temporary however, because glaciers on Svalbard are retracting and many are already grounded and not calving ice into the sea any longer.
MOSJ indicators (Environmental Monitoring of Svalbard and Jan Mayen):
Awaiting results from MOSJ…