Beluga Whale

Classification

Class: Mammalia
Order: Cetacea
Suborder: Odontoceti
Family: Monotontidae
Genus: Delphinapterus
Species: leucas
Common names: Beluga, Sea Canary, White Whale
Irish Name: An míol mór bán
 

Key Identification Features

Max. adult body length/weight: 5m / 1500 kg.
Blow:Not obvious as it is inconspicuous, low and steamy, but may be heard at a range of several hundred metres on calm days.
Head: The head is relatively small when compared to the body and is bulbous in shape with a small short beak. The melon is rounded and can change shape and resonates during sound production. The mouth line is broad and there is a distinct well-defined crease behind the blow- hole. The mouth line is broad and the Beluga appears to create a variety of facial shapes or expressions by altering the shape of its forehead and lips. This can result in an apparent smile, frown, or whistle, and may be related to the production of sound or form some other means of communication. Belugas have a stocky body, with a distinct neck that displays a considerable degree of flexibility due to its neck vertebrae not being fused.
Dorsal Fin: As is common among cetaceans living among the pack ice, they have no dorsal fin. Instead, a narrow ridge extends for about 50cm and may consist of a series of dark bumps. This dorsal ridge is often marked with a series of nicks, cuts and scrapes – from both abrasion on the sea ice and from polar bear attacks. The body of a well-fed Beluga has a lumpy appearance, with folds of fat along the sides of the body; thick blubber protects them from the extreme cold.
Pectoral Fins: The pectoral fins are short, broad and spade-like. They curve upwards in male Beluga, becoming more pronounced with age.
Colouration: Beluga whales are born with a dark late grey body, which may have a pinkish tinge. As they age they become whiter with a blue tinge, before eventually becoming pure white once sexually mature at 5 to 10 years of age. The flukes also change shape having a straighter trailing edge in newborns, becoming more convex as a juvenile and adult with a distinct notch in the centre and a dark brown trailing edge.
Markings: Identification of individual belugas is possible using a combination of naturally occurring features – scars; caused by abrasion and cuts from the ice and also from polar bear attacks, and colouration and pigmentation that varies among individuals.
Average adult body length/weight: 4m / 1000 kg
Average length/weight of calf at birth: 1.5m / 80 kg
 

Field Identification

The Beluga whale is normally a slow swimmer, spending much time at the surface and moving in an undulating motion. The dive sequence typically consists of 5-6 shallow dives in a minute, followed by a deeper dive lasting about a minute.
 

Species Similar in Appearance

Unlikely to be confused with any other species in Irish waters, although adult Rissos dolphins may appear almost white.
 

Behaviour

The Beluga rarely breaches but is known to lob tail and spy hop regularly. They are very inquisitive and have been known to lift over 1m of their body out of the water, turning and nodding their flexible necks, possibly to look for predatory polar bears that use breathing holes in the ice from which to launch their attacks.
 

Status and Distribution

The Beluga whale is endemic to the high latitudes of the Northern Hemisphere and is found in discrete populations in the arctic and sub-arctic and is circumpolar in its distribution. Five main populations are recognised world-wide: Bering Sea, Chukchi and Okhotsk Sea, high Arctic Canada and west Greenland; Hudson Bay and James Bay, Canada; Svalbard area and the Gulf of St. Lawrence Canada.

Seasonal distribution is directly related to ice conditions but most populations do not make extensive migrations. In Canada, Beluga whale’s movements have been documented. From the Bering Sea in winter, Belugas migrate to the MacKenzie Delta, Beaufort Sea and Amundsen Gulf. From West Greenland, they migrate to Lancaster Sound and Prince Regent Inlet. From the Davis Strait and Hudson Strait they migrate in summer to Cumberland Sound, Ungava Bay, and Hudson Bay. A population in the St. Lawrence estuary remains year round.


Satellite telemetry has shown that (at least some) belugas undertake more extensive migratory movements than previously thought.

The current Beluga whale world population has been estimated at about 100,000. Many of the 16 stocks have been seriously reduced by over-exploitation. Estimates of 55 - 60,000 Belugas have been made from surveys of the Bristol Bay-MacKenzie Delta area, Bering-Chukchi, Hudson and James Bays, Lancaster Sound, and Spitsbergen.
 

Where and When Best Seen in Ireland

The Beluga is only a very rare visitor to Irish waters, there are no records of strandings and only two authenticated sightings in the 20th century – one off Clare Island , Co. Mayo and the other in Cork Harbour in 1987. Both were of single animals.
 

Food and Feeding

Beluga whales have a relatively varied diet feeding mainly on squid but also on octopus and crustaceans and on various small fish, including salmon, herring and cod. They hunt in a variety of ways often herding or chasing fish into a group before capturing them, driving fish from the deep to the shallow surfaces, or by rushing through a group of fish and gulping them as they swim, resulting in the capture of larger species such as cod and haddock.

The prevalence of mud, stones and algae in the stomachs of Belugas shows that they often feed on the bottom. Less mobile or sedentary prey, such as benthic organisms, make important prey for weaning calves. They seem to rely upon suction as a feeding mechanism making use of the mobile, flexible lips. Belugas use their well-adapted and sensitive hearing and echolocation to assist in foraging. It has been suggested that Belugas visit estuaries in summer principally to feed, but other studies suggested they do so to moult.
 

Reproduction and Life Cycle

Max. life expectancy: 40 years.
Average life expectancy: 20 -25 years.
Mating Occurs: April - May. Season of birth: July – August.
Gestation: Approximately 14-15 months.
Beluga whales produce a calf every three years, and this calf is weaned after 20 - 24 months.
 

Social Structure

Beluga whales are sociable animals and are typically seen in pairs or in polygamous (having more than one mate) groups of 5-20. Some aggregations of 1,000 or more are encountered. The sexes form separate schools outside the breeding season, the calves remaining with the mother.
 

Conservation Issues

The only known predators of the Beluga whale appear to be polar bears, killer whales and man. Belugas occasionally get trapped under the ice and without a breathing hole will die. The Inuit people have traditionally hunted the Beluga as a subsistence resource but in the 20th century they were subject to over-exploitation. Contamination of the oceans by toxic man-made chemicals and other pollutants has had a huge impact on Beluga whales, particularly in the St. Lawrence River. So much so that stranded or dead Beluga whales are classified as toxic waste due to the high levels of contaminants in their bodies. The effects of oil and gas exploration, other industrial activities, and the development of hydro-electric plants on rivers used for calving are also of concern.
 

Stranded Animals

The white colouring and general size and shape of this animal aids in identification of stranded animals. The lack of a dorsal fin and the transverse slit of the blowhole located just in front of the neck crease are also diagnostic. There are 8 – 11 teeth in each side of the upper jaw, and 8 – 9 in each side of the lower jaw.
 

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