BEARDED SEAL
The bearded seal (Erignathus barbatus), also called the square flipper seal, is a medium-sized pinniped that is found in and near to the Arctic Ocean. It gets its generic name from two Greek words (eri and gnathos) that refer to its heavy jaw. The other part of its Linnaean name means bearded and refers to its most characteristic feature, the conspicuous and very abundant whiskers. When dry, these whiskers curl very elegantly, giving the bearded seal a "raffish" look.
Bearded
seals are the largest northern phocid. They have been found to weigh as much as
300 kg (660 lb) with the females being the largest. However, male and
female bearded seals are not very dimorphic.
The only
member of the genus Erignathus, the bearded seal is unique
in that it is an intermediate. Bearded seals belong to the family Phocidae which contains two
subfamilies: Phocinae and Monachinae. The bearded seal possesses
characteristics of both of these subfamilies.
Fossils
first described in 2002 indicate that, during the Pleistocene epoch,
bearded seals ranged as far south as South Carolina.
Bearded seals get their name from their... moustache!
Sub Species
Two subspecies are recognized
E. b. barbatus from the central Canadian Arctic
east to the central Russian Arctic including Greenland, Iceland, Jan Mayen, and
Svalbard, and south to Norway and Newfoundland; and
E. b. nauticus from the central Canadian
Arctic west to central Arctic Russia, south to the Karaginsky Gulf, Russia, and
Bristol Bay, Alaska, also including the Sea of Okhotsk south to northern Japan.
Distinctive characteristics
Bearded seals are large phocids with
a relatively small head and short fore flippers. The head is rounded and
somewhat narrow, and the eyes are relatively small and close-set. The muzzle is
wide and fleshy, with widely-spaced nostrils. The whiskers are sufficiently
conspicuous to have given rise to the common name, “bearded” seal. The abundant
vibrissae are pale, long, curved downwards, densely packed, and not beaded as
in other Arctic phocids. When dry, the vibrissae curl inwards at the tips. The
fore flippers are short, relatively broad, and strong, with robust claws.
Unlike any other phocid, the bearded seal's fore flippers end in digits of about
the same length, or with slightly longer middle digits. The result is a square,
or slightly rounded, end to the fore flippers. Also, unlike all other Arctic
phocids, bearded seals have four retractable mammae instead of two.
Adults are slightly darker above
than below. Body coloration varies considerably and can be from light to dark
gray, or tawny brown to dark brown. There can be rust coloration on the head,
back of the neck and top of the fore flippers. The lanugo is shed in the uterus
before birth and pups are born with a somewhat longer, dark brown to dark
bluish gray, wavy coat. There are pale areas on the muzzle, around the eyes,
and sometimes on the crown and top of the back. A line of dark color runs from
the top of the head between the eyes and along the bridge of the nose.
Size
Adults range up to 2.5 m in length. Adult females are slightly longer than males. In the Bering Sea, males reach 262 kg and females 361 kg. Pups are, on average, about 1.31 m and 33.6 kg at birth.
Life Span
Typically both male and Female Live up to 25 years; Maximum 31 years.
Gestation Period 335 days.
Can be confused with
Bearded
seals regularly share their range with seven other Arctic and subarctic
phocids, including harbor, spotted, ringed, ribbon, harp, hooded, and gray
seals. Of these, most are smaller, spotted (or otherwise uniquely colored), or
generally distributed further south. In the North Atlantic, the bearded seal is
most likely to be mistaken for the similar-sized hooded seal when hauled-out,
except when the distinctive coloration of the hooded seal can be seen.
Distribution
Bearded seals have a circumpolar distribution in the Arctic, generally south of 80°N. They are subarctic in some areas, such as the lower Bering Sea, Sea of Okhotsk to northern Japan, and western North Atlantic, where they reach the Gulf of St. Lawrence. They usually restrict themselves to sea ice and stay in relatively shallow continental shelf areas of continuously moving ice, where open leads and polynyas regularly form. In some areas, they are known to haul-out on shore, ascend streams, or live a pelagic existence away from ice and land for long periods of time.
Ecology and
Pups are born in the open on the
surface of the pack ice, from mid-March to early May. After the breeding
season, many seals migrate northward with the retreating ice, returning south
again as the ice advances in fall and winter.
Bearded seals are solitary and
rarely haul-out on the same ice floe together, and even then, maintain healthy
distances from neighbors. Mother and pup pairs are an exception to this rule.
At times, bearded seals seem to concentrate in an area and this may be due to
shifting winds and currents driving ice floes together or because of favourable
feeding opportunities. Bearded seals are exceptionally wary and always haul-out
and position themselves with their head very close to the water at the edge of
an ice floe, along a crack, or by a hole.
In the water, bearded seals can be
found “bottling,” or floating vertically head-up, asleep. When startled, they
bolt into the water and swim with strong strokes of the fore flippers with the
head held up in a manner that looks like they are rising and surging through
the surface of the water. When in the water and disturbed by a passing ship,
bearded seals will roll steeply forward to dive, raise the lower back and rear
flippers in the air and splash the flippers on the surface. This is often done
repeatedly as the seal swims away from the direction the ship is traveling.
Bearded seals primarily feed on or
near the bottom, and live in shallow areas overlying the continental shelf.
They generally dive to depths of 200 m or less and frequently are found in much
shallower areas. The longest dives recorded have been 20-25 minutes, with most
dives lasting less than 10 minutes. They are quite vocal in the water and are
known for their oscillating frequency-modulated songs that can last more than a
minute and be heard in air and for long distances underwater. Singing has
largely been attributed to males, but it is likely that females sing as well.
Besides humans, predators include polar bears, killer whales and Greenland
sharks.
Predation
Bearded Seals have two main predators, Polar bears and killer Whales. Polar bears hunt seals by Waiting near a breathing hole for their prey to surface. However, breathing holes of bearded seals usually form domes or capes of ice that they must dig through to reach the surface. This may serve as a defensive strategy, obscuring breathing hole Positions and making them more difficult for polar bears to locate. Killer whales do not actively hunt bearded seals, but eat them opportunistically. Although rarely observed pups of bearded seals are occasionally eaten by walruses. Bearded seals are also taken by humans through subsistence fishing by Native Americans in Canada and Alaska.
Feeding and prey
Bearded seals feed on a large diversity of demersal fish species and invertebrates that live on, and in, the bottom. Different combinations of prey dominate feeding at different times of year and in different locations, and juveniles and adults have different prey preferences. In the Bering and Chukchi seas fishes taken included capelin, Arctic and saffron cod, long-snouted prickle backs, sculpins, flatfishes, several snail fish species, and eelpouts. Invertebrates were dominated by several species each of crabs, clams, snails, amphipods, shrimps, marine worms and octopus.
Exploitation
On March 28, 2008, the U.S. National Marine Fisheries Service initiated a status review under the Endangered Species Act (ESA) to determine if listing this species under the ESA is warranted. All bearded seals are protected under the Marine Mammal Protection Act, and determined by the IUCN to be classified as a "least concern" for extinction. This classification was determined due to various factors including, widespread distribution, stable population size, as well as alternating prey resources. NOAA determined that the factors influencing any change in conservancy status of the bearded seal may include: loss of sea ice by climate change, by catch from commercial fishing gear, and hunting. Their main predators include polar bears; however, typically pups around age 2 are attacked within birthing lairs, leaving older juveniles and adults commonly unharmed. Due to climate change, factors such as loss of sea ice, as well as decrease in prey population may create negative results on the bearded seal population in the future. Therefore, monitoring of the species as well as influences of human activity, will be vital to ensure species stability.
Threats and status
Native peoples of the Arctic have hunted bearded seals for subsistence for thousands of years. This practice continues to the present, with several thousand being taken annually throughout their circumpolar Arctic range. Bearded seals provide numerous products, including food for humans and sled dogs, oil for lamps, skins for clothing, boats and tent coverings, and leather for sinews, to name a few, and they are important in many other culturally important ways. The worldwide population is estimated at 500,000 with more than half of these thought to live in the Bering and Chukchi seas. Commercial exploitation by Soviet whalers in the Sea of Okhotsk and Bering and Chukchi seas during the mid-twentieth century resulted in harvests of thousands to more than 10,000 animals per year lasting several decades.
Factors hypothesized include
The direct and indirect effects of large-scale commercial fisheries on key prey species, long –term ecosystem shifts, and changes in behavior by a primary predator, the killer whale, or a combination of these factors.
IUCN status Least concern
Bearded Seal Pup
Bearded Seal On Ice
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