Beluga

April 19, 2012, 4:29 pm
Content Cover Image

Beluga whale swimming underwater. Source: Stanislav Krejčík/Bio Lib

caption Beluga from Churchill River near Hudson Bay. @ Ansgar Walk
caption Size comparison of an average human and a beluga. Source: Chris Huh

Conservation Status:

Scientific Classification

Kingdom: Animalia
Phylum:--- Chordata
Class:------ Mammalia
Order:-------- Cetacea
Family:-------- Monodontidae
Genus:--------- Delphinapterus
Species:---------Delphinapterus leucas (Pallas, 1776)

Common Names:
Beluga
Beluga Whale
Belukha
White fish
White whale; Beluga
Buluga
Sea canary
White whale

The Beluga whale (Delphinapterus leucas) is one of two species in the Monodontidae family, the other being the Narwhal. The snow-white Beluga whale is one of the most distinctive of all cetaceans (a group including, dolphins, whales and porpoises).

The stocky body ends in a particularly small head, and adults develop their striking white colouring as they mature. Belugas lack a dorsal fin and their genus name Delphinapterus means “dolphin-without-a-wing”.  In place of a dorsal fin, there is a ridge of toughened skin along the back that tends to be more pronounced in mature males. Unlike most cetaceans, Belugas have an extremely flexible neck and can turn their heads almost 90 degrees to the side. Their lips are also flexible, forming a variety of facial expressions.

Belugas use a wide range of vocalisations such as clicks, grunts, squeals, screeches and whistles. These sounds can be heard through the hulls of ships and the Beluga was nicknamed the sea canary by early Arctic sailors. Belugas are a Northern Hemisphere species, and have a thick layer of blubber that enables them to live in icy polar waters.  This layer of blubber may be up to 15 centimetres thick which is characteristic of cold climate species.

Belugas are highly social animals, and in the summer months thousands of individuals can be seen gathered in rivers and estuaries.  Females with calves will join together, and males will form large bachelor groups.  During these summer months, large numbers of Belugas gather in estuaries (such as in the Churchill River discharging to Hudson Bay) in order to give birth and to moult. They drag themselves on the gravel bed and shed the yellow, withered skin of the previous year to once again become gleaming white. While the majority of Belugas migrate annually, some populations remain close to the shore in rivers and estuaries year round. 

Females are sexually mature around five years of age.  They usually give birth to a single calf after a gestation period that lasts just over a year. Mother and calf have an extremely strong bond and swim close together.  The calf will continue to feed on its mother’s milk for up to two years. Belugas breed in the winter and give birth during the summer months.

Belugas are able to dive to depths of over 1000 metres, but spend most of their time on the surface of the water swimming slowly. During winter months it may be necessary for individuals to create breathing holes in the ice, which they can do with their heavy head. Their flippers are capable of a wide-range of movement and enable Belugas to manoeuvre themselves effectively.

Belugas feed on a wide variety of fish, bottom-dwelling invertebrates and worms.  Most of the prey is found on the seabed, and it is thought that the highly flexible lips may be used to suck prey into the mouth. Sounds can be used to detect prey; the enlarged melon is an electro-receptor for sounds that are sent out from the nasal passages.

These whales are thought to live up to 50 years in the wild.  Their predators include Killer whales, Polar bears and humans. Although the ice can protect the Beluga from predators, they can become trapped by their reliance on breathing holes in the sea ice.

Physical Description

Key physical features are: endothermic; homoiothermic; and bilateral symmetry.

The Beluga whale is also known as the White whale for its milky white skin. It is the only species of whale that is entirely white, although it is born gray and whitens gradually with age. These whales lack a dorsal fin, but have a shallow ridge along their back. Their appendages are narrower and pointier than that of the Narwhal.  Belugas also have a melon-shaped head, which is the center for echolocation.

They are three to five metres in length and have an average body mass of 1.6 tonnes (3500 lbs). Fifty percent of the body mass is fat, a marked increase relative to other non-Arctic whales, whose body is only twenty percent fat. The blubber is 10 centimetres thick and their skin is tougher than that of other whales.  Their thick skin has been tanned and used as leather by the native people of the Arctic.  Belugas are sexually dimorphic, with the males slightly larger than the females. Females average 1350 kilograms (kg), with a range of 540 to 790 kg; correspondingly, males have a mean body mass of 1500 kg in body mass, with a characteristic range of 800 to 1500 kg (Paine, 1995). The length range of Beluga is 3.4 to 4.9 metres for males and 3.3 to 4.0 metres in females.

Belugas have a fusiform body shape and a large melon on the head. The melon is composed of fat and is believed to focus echolocation tones. The Beluga manipulates the melon while creating sounds and whistles.  The melon can also be used as an indicator of health; poorly nourished Belugas have low flat melons while well-fed individuals have round melons.  The melon can also indicate emotional state; aggressive individuals often raise their melons forward. There are no dorsal fins, which helps them conserve heat and navigate through ice packs. They have small blunt flippers they use to steer and forage for food in the sediment.  Thirty-eight conical shaped teeth are present.  The teeth are used to grab and tear their prey.

Behaviour

Belugas aggregate in herds of hundreds to thousands. Grouping of different pods is still uncertain, but age and sex seem to play a role in the grouping.  They are rarely seen breeching, although they can rise vertically out of the water about one third of their body length. They swim approximately nine to ten kilometres per hour. Belugas are constantly vocalizing and swimming around, over, and under each other. They also play with objects in the water together or by themselves. These objects include wood, plants, dead fish, and bubbles that they created (Paine, 1995).

Communication

Communication is achieved by using the melon for echolocation.  Belugas employ a high frequency band for communication. Their airborne vocalisations are sufficiently loud that they sound like birds, which is why they were nicknamed sea canaries. Their voices sound like chirps, whistles, and squawks.  They are considered to be among the most vocal species of cetaceans. They use their vocalisations for echolocation, mating, and communication.

Belugas also use body language such as grinding their teeth or splashing around. Some communication undoubtedly occurs when calves are in contact with their mothers (Bonner, 1989; Paine, 1995).  Other sensory perception channels are: visual, tactile, acoustic, echolocation, vibrations, and chemical.

Reproduction

Key reproductive features: iteroparous; seasonal breeding; gonochoric/gonochoristic/dioecious (sexes separate); sexual; fertilization; viviparous; and delayed implantation.

Belugas tend to mate from late February to early April. It takes four to seven years for females to sexually mature, and seven to nine years for males (Bonner, 1989).  Males pursue the females, making a variety of noises. The male throws down his tail and bends violently, he then throws his head up and down as his melon vibrates to ward off other male competitors.  The male and female swim in harmony and caress each other, until she swims underneath his belly. She puts her belly up against his and they appear to mate with consent (Paine, 1995).  Males are not monogamous; a dominant male will often mate with several females during the mating season.

Gestation lasts about 14 months and calves are born during the summer migration. However, it is a possibility that these creatures have delayed implantation. Calves are born during the months of May through July. Females can give birth to one or two calves at a time, but twins are rare.  When calves are born they are about 1.4 metres and 82 kg and remain close to their mothers for the first two years.  The calf is very well developed and has a grayish coloration. The nursery pod stays around during the delivery and then all of them leave except the mother and a young teenage nursemaid. A nursery pod consists of several female Belugas and their calves. The baby stays in-between the two females as they swim, pulling the calf with the current.  The calves are born with small amounts of fat and need to be birthed in warm waters to avoid hypothermia.  They quickly build up their fat storage by nursing their mother’s fat rich milk.  The calf is totally dependent on the mother’s milk for a year, but lactation lasts 1.5 to 2.0 years (Paine, 1995). Offspring are precocious, and able to swim alongside their mothers from birth. The mother provides protection and guidance for the offspring, as well as milk.  Females reproduce every 2 to 3 years and cease reproduction in their early twenties (Lentifer, 1989) (Bonner, 1989; Lentifer, 1988; Paine, 1995).  To successfully reproduce the female Beluga needs a clean environment free of toxic chemicals.  When high levels of pesticides and flame retardants are present, females can suffer from debilitating reproductive cancers and high embryo mortality rates.

Lifespan/Longevity

The average life span for females is thought to be about 32 years and that for males about 40 years. A small number of Belugas have been known to live for up to 50 years.  Age can be determined through an examination of the teeth. Predation and ice entrapment are common causes of premature death (Lentifer, 1988).

Distribution and Movements

Belugas are found in Arctic waters around northern Russia, North America, Greenland and the Norwegian archipelago of Svalbard. Most populations migrate north in the spring, then south in the autumn once the ice starts to form.

Subpopulations

The IUCN Red List reports:

The global population consists of numerous subpopulations with varying degrees of differentiation (hereafter the terms subpopulation and stock are used interchangeably). The International Whaling Commission’s Scientific Committee (IWC 2000) organized information on Belugas on the basis of 29 provisional management stocks. Some of the stock boundaries overlap spatially and seasonally, complicating assessment. Many of the subpopulations or stocks maintain distinct or contiguous geographical ranges during the summer months but mix during the spring and autumn migrations and share common wintering quarters. A few stocks do not migrate and remain in the same waterways throughout the year.  While good abundance estimates are available for some Beluga subpopulations/stocks, the sizes of others are virtually unknown. Many cetaceans are still understudied, including the Beluga, due to these difficult research conditions. Total estimates worldwide are above 150,000 animals, but many portions of the range are unsurveyed. While some subpopulations number in the thousands, certain subpopulations only number in the hundreds. The following estimates for subpopulations/stocks or regions range from relatively precise abundance estimates to rough approximations of numbers in the late 1990s or early 2000s.

Alaska
Cook Inlet: The number of Beluga whales in Cook Inlet is estimated from counts by aerial observers and aerial video group counts (Hobbs et al. 2000b; Lowry et al. 2006). The most recent published estimate at the time of the present assessment (May 2008) was 302 (CV=0.16) in 2006 (Angliss and Outlaw 2007). In addition, the National Marine Fisheries Service had indicated via a web posting that the point estimate from the 2007 aerial survey was 375.  This subpopulation is not a seasonal migrant and remains at the inlet year round.  This population declined drastically due to overharvesting.  In the last four decades the estimated number of Belugas dropped from 1300 to 375 individuals.  From 1994 to 1998 the Belugas were hunted beyond sustainable levels.  During this time frame there was a limit set to 14 whales per year, but close to 72 whales were removed from the stock. The Cook Inlet Beluga was classified as critically endangered in 2006 by the International Union for the Conservation of Nature. This isolated subpopulation is believed to be genetically diverse because of geographical barriers.

Bristol Bay: Most recently (1994), the number of Beluga whales in Bristol Bay was estimated at 1,555 (Lowry and Frost 1999). This estimate was based on a maximum count of 503 animals, which was corrected using radio-telemetry data for the proportion of animals that were diving (Lowry and Frost 1999) and for the proportion of newborns and yearlings not observed due to their small size and coloration. Surveys in 1999 and 2000 resulted in maximum counts of 690 and 531, which can be extrapolated to population estimates of 2,133 and 1,642, respectively (L. Lowry, University of Alaska Fairbanks pers. comm. to K. Laidre, Jan. 2007).

Eastern Bering Sea: Aerial surveys of Norton Sound, the summering site for the eastern Bering Sea stock, were conducted in 2000. Preliminary analyses produced an uncorrected estimate of 5,868 animals; when corrected for animals not visible at the surface and for newborn and yearling animals not observed due to their small size and dark coloration, the estimated population size for Norton Sound is 18,142 (CV=0.24) (R. Hobbs, AFSC-NMML pers. comm. 01/07; Angliss and Outlaw 2005).

Eastern Chukchi Sea: Frost et al. (1993) estimated the minimum size of the eastern Chukchi Sea stock of Belugas at 1200 individuals, based on counts of animals from aerial surveys conducted during 1989-91. The total corrected abundance estimate for the eastern Chukchi stock is 3,710.

Shared Alaska/Canada
Eastern Beaufort Sea/Beaufort Sea: The most recent aerial survey, conducted in July 1992, resulted in an uncorrected estimate of 19,629 (CV=0.229) (Harwood et al. 1996). The corrected population estimate was 39,258 animals (Angliss and Outlaw 2005).

Canada
Cumberland Sound: This stock numbers about 1500 animals and is thought to have increased since the 1980s (COSEWIC 2004).

Ungava Bay: The Ungava Bay stock is too small to estimate. Hammill et al. (2004) recently estimated it at <50 animals; none were seen on a survey conducted in 2001.

West Hudson Bay: There are estimated to be more than 23,000 Belugas in western Hudson Bay and more than 1300 along the southern Hudson Bay coast (Richard 1991).

East Hudson Bay: Belugas in Eastern Hudson Bay have declined from 4200 (SE 300) in 1985 to 3100 (SE 800) in 2004 (corrected estimates) (Hammill et al. 2005).

St Lawrence River: The St. Lawrence subpopulation is estimated to be in the order of 900-1000 individuals. There is no evidence of a significant trend in abundance since 1988 (COSEWIC 2004).  This subpopulation does not migrate and remains in the river and estuary year round.  The population has not shown a significant amount of growth during several decades of surveys and is considered endangered.  This could be due to the rivers high level of industrial contaminants, ship collisions, increase in noise pollution, and climate change.  The St. Lawrence River Beluga has shown a lack of genetic variation meaning that this group remains segregated from migrating subpopulations.

Eastern High Arctic/Baffin Bay: A survey in 1996 estimated 21,213 Belugas (95% CI 10,985 to 32,619) in the waters surrounding Somerset Island: Barrow Strait, Peel Sound and Prince Regent Inlet (Innes et al. 2002). This estimate takes into account both whales missed by observers and those that might have been unavailable for detection due to diving behavior. It includes whales that move to West Greenland during the winter.

Shared Canada/Greenland
West Greenland: Aerial surveys flown in late winter in West Greenland between 1981 and 1994 found that Beluga numbers had decreased by 62% during that period, probably because of overharvesting (Heide-Jørgensen and Reeves 1996). Further surveys in 1998 and 1999 confirmed the decline and found 7,941 (95% CI: 3650-17278) Belugas in West Greenland, including whales missed by the observers and whales that were submerged during the survey (Heide-Jørgensen and Acquarone 2002). Heide-Jørgensen et al. (2003) estimate that approximately 30% of the Eastern Canadian high Arctic/Baffin Bay Beluga stock migrates to West Greenland for overwintering.

Svalbard
Belugas have never been surveyed around Svalbard. Pods numbering into the thousands are sighted irregularly around the archipelago, and pods ranging from a few to a few hundred individuals are seen regularly (Gjertz and Wiig 1994; Kovacs and Lydersen 2006).

Russia
Eastern and Central Russian Arctic: There are no rigorous abundance estimates for the Eastern and Central Russian Arctic (Boltunov and Belikov 2002). Rough estimates of a few thousand in Anadyr Gulf and a few thousand in the western Chukchi and eastern East Siberian Seas were summarized in a table compiled by the IWC Scientific Committee (IWC 2000). In addition to those stocks, Belugas from some Alaskan stocks (e.g. eastern Bering Sea, eastern Chukchi Sea, and Beaufort Sea stocks) move into eastern Russian waters during the winter. The IWC table mentioned above (IWC, 2000) indicates a rough estimate of 18,000-20,000 in the Okhotsk Sea.

Western Russian Arctic: Belugas in the Western Russian Arctic occupy four major areas: southern Barents Sea and White Sea, southern Barents and Kara seas, coastal waters of the Kara Sea, and western portion of the Laptev Sea. They may share wintering grounds to some extent. It is estimated that a combined 15,000 to 20,000 individuals inhabit the White, Barents and Kara Seas of the Western Russian Arctic (Boultunov and Belikov 2002). The White Sea hosts a resident population of Belugas numbering about 1,000 over-wintering individuals. In summer, this number is augmented by animals from the Barents Sea.

Habitat

The Beluga whale is a pelagic species inhabiting cold arctic waters.  They are located in the Arctic and subarctic, often in or near glacial ice.  Belugas are circumpolar and found throughout the Arctic, but a few populations have discontinuous distribution like the Cook Inlet and St. Lawrence populations.  Some groups remain around Northern Alaska and Canada traveling between the Pacific Ocean and the Chukchi and Beaufort Seas.  

During the winter months, Belugas congregate around areas of loose pack ice.  Wind and ocean currents provide cracks in the ice, leaving breathing holes open during the winter months.  These breaks in the ice are called polynyas.  Migrating populations spend the winter months in these ice packs and feed from the polynyas.  They supply an abundance of food and support several Arctic marine species.  The Beluga shares the winter polynyas with Narwhals, Bowhead whales, seals and walruses.  This ice also protects Belugas from their predators, the Polar bear and Killer whale.     

Belugas inhabit coastal waters, estuaries, shelf breaks, and deep basins during the summer months.  They can also be found around inlets, fjords, channels, bays, or any shallow water that is warmed by continuous sunlight. These warmer waters are usually eight to ten degrees Celsius (Paine, 1995).  They gather at the mouths of rivers where they feed on benthic organisms, socialize, and deliver their offspring. The warm brackish water also allows them to shed their winter skin.

Food and Feeding Habits

Belugas are dietary generalists feeding on smelt, flatfish, flounder, sculpins, salmon, and cod. They also feed on invertebrates such as crab, shrimp, clams, worms, octopus, squid, and other bottom dwelling creatures. Species that have a diverse diet are referred to as dietary generalists.  Belugas compete with other marine species for their dietary needs but they benefit from their diverse diet.  Their echolocation is used to locate faunal prey. Since they do not have big, sharp teeth to puncture their prey, they use suction to draw it into their mouths. Consequently, everything must be eaten whole. Prey cannot be too large, therefore, or the beluga will choke on it (Lentifer, 1988; Paine, 1995).  Belugas are considered apex predators because they are high on the food chain with only a few known predators.

Belugas consume large amounts of fish, especially since they travel in herds of hundreds to thousands. This undoubtedly causes some regulation of fish populations. Belugas also seem to have a parasite called Pharurus pallasii, thought to infect the hearing organs. However, it is not known if this parasite is harmful to the Beluga (Lentifer, 1988).

The Beluga feeds close to the shore on prey that can come into contact with several parasites.  Belugas can also contract the parasite T. gondii from ingesting infected prey.  This parasite causes toxoplasmosis and infects the lungs, brains, and eyes of its victims.  This parasite is excreted from infected animals and it is believed to be washed into waterways during heavy rains and water table fluctuations.  T. gondii has been determined to be a cause of death for several stranded Belugas from the St. Lawrence River. 

Predation

The known predators of Belugas are Killer whales, Polar bears and humans. Polar bears will attack Belugas in the same way they would attack a seal, which entails lying in wait at breathing holes. Killer whales come into Beluga territory around August. Belugas can usually hear Killer whales, so this makes it difficult for Killer whales to attack them. Also, the conspicuous fin makes it almost impossible for a Killer whale to maneuver in ice.  Humans hunt Belugas for their skin, meat and oil (Paine, 1995).  These whales are particularly vulnerable to predation due to their high fidelity for certain migratory routes. 

Economic Importance for Humans

Belugas have traditionally been hunted for food and oil, but only with the advent of commercial whaling did the harvest become too large to sustain (Paine, 1995).  Whaling previously provided humans with a profit but there are now regulations regarding the sale of Beluga meat and skin. The sale of Beluga is still allowed in some regions but only among the native Inuit people.

The Beluga provides ecological and economical support to Inuit communities through hunting.  This practice is performed by native people to provide traditional food.  The hunting exists in some villages where sustenance hunting is an annual event.  Sustenance hunting is intended to feed a group or family in order to survive.  The Beluga meat and blubber provide the Inuits with an affordable source of food.  Beluga hunting is used as a way to continue knowledge and traditions that have been passed down through generations.  The practice also encourages the natives to socialize as they hunt together and share their catch.  They believe that the Beluga is a sentient being and that is must be respected and treated a specific way in order to offer itself to the Inuit hunter. 

Harvesting Belugas has been a part of their culture for generations but as their populations increase and the technology used during the hunts change there could be a noticeable decline in Beluga populations.  Beluga hunts have been banned in some regions like the Cook Inlet and the St. Lawrence Estuary, but other areas do not have restrictions.  Beluga migration routes can travel through regions without hunting limitations to areas with strict limitations.  This often causes disagreements between neighboring communities because they view the limitations as unfair.  The Inuit communities also differ in the ways they hunt and their usage of whale meat and blubber.  Some regions use harpoons and nets and others use shot guns from the rocks of the shore.  There are regions that do not consume the entire beluga and only use its blubber. In some regions hunting restrictions and the importation of food sources have lead to a decrease in Beluga harvests.

Now, because of their large social groupings, they provide ecotourists with entertainment (Lentifer, 1988).  This is the case in the St. Lawrence River where thousands of tourists visit each year to see the whales.

Threats and Conservation Status

The Beluga is classified as near threatened (NT) on the IUCN Red List, Appendix II of CITES , and Appendix II of the Convention on Migratory Species (CMS or Bonn Convention).  The Cook Inlet subspecies is listed as critically endangered (CR).

In some parts of the Beluga whales range, particularly in Canada and Greenland, intensive hunting represents an ongoing threat to Belugas. Traditional hunting takes advantage of the migration routes that bring large groups of Belugas close to land.  Overhunting has already led to a dramatic decrease in smaller populations.  One overharvested population (or "distinct population segment" in the language of the U.S. Endangered Species Act), the Cook Inlet Beluga whale of Cook Inlet in southeastern Alaska, was listed as critically endangered by the U.S. National Oceanic and Atmospheric Administration (NOAA) in October of 2008. In December of 2009, NOAA proposed designating more than a third of Cook Inlet as critical habitat for the remaining approximately 300 Cook Inlet Beluga whales.

Today the widespread hunting of Beluga whales is prohibited under the International Moratorium on Commercial Whaling; however, small quotas are permitted to local people who depend upon the harvest. The Alaska and Inuvialuit Beluga Whale Committee was established in 1988 and encourages dialogue between native hunters, conservationists and government representatives as well as carrying out stock and hunting assessment of the Alaskan and Canadian populations of Belugas. 

In a few instances hunting is compounded by the less direct and less easily quantified threats of disturbance by vessel traffic (e.g., St. Lawrence estuary, river mouths in eastern Hudson Bay), habitat modification (e.g., large hydroelectric dams in rivers flowing into Hudson Bay and James Bay), contaminants (e.g., St. Lawrence estuary), and possibly incidental catch in fisheries (wherever entangling gear overlaps the species range) (IUCN 2009).  Competition with humans for fish, such as salmon, can lead to net entanglement and ship collisions.

Global climate change may have potential negative impacts on Beluga whales. Particular populations are more vulnerable to oil spills and industrial accidents, but all populations are subject to climate change.  Climate changes are well documented and are causing the ice caps to melt and the sea levels to rise.  The rise in sea level will wash pollutants from the land into the waterways causing health issues for all marine species.  The most serious impacts of climate change on Belugas may not come directly from the effects of weather conditions, but rather indirectly from the role that regional warming and reduced sea ice play in changing human activities. Extensive ice cover and extreme winter conditions (including both darkness and cold) have always limited human activities in the Arctic, and many regions have remained inaccessible to ships and other vessels. As Arctic ice cover declines and the passages between northern landmasses become more navigable, humans will gain easier access to formerly pristine areas that have long served as refuges for Belugas (IUCN 2009).

The number of vessels sailing through the Arctic for gas and oil exploration/extraction, commercial shipping (for both transportation and tourism), and fishing has already increased. Further reductions in sea ice are likely to accelerate this trend in coming decades. With the increase in ship traffic, ship strikes are likely to become an increasingly significant cause of Beluga injury and death. Belugas detect and respond to the presence of icebreaking ships over great distances (up to 50 km). Industrial noise (e.g., from ships, seismic surveys, and offshore drilling), likely disrupts Beluga behaviour and may impair the ability of Belugas to communicate, forage efficiently and generally sense their environment. Noise-producing activities are already ongoing or planned in many areas used by large populations of Belugas, including the Beaufort and Chukchi seas, West Greenland, and Hudson Bay (IUCN 2009).

As Arctic waters become warmer and patterns of circulation, salinity, and nutrient input change, species that previously were not present in the Arctic will be able to move further north and remain there for longer. This could have two major types of effects on Belugas. First, species such as Minke and Humpback whales as well as seals and other predators may directly compete with Belugas for food resources. Second, species such as Killer whales may have more opportunities to prey on Belugas. Both of these factors could negatively affect Beluga populations (IUCN 2009).

Loss of sea ice and increased ocean temperatures will affect the distribution, composition, and productivity of prey communities and in turn influence the ability of Belugas to find and catch suitable prey. The warming of the Arctic will cause a disturbance in the food web impacting several marine species. Migrating Belugas rely on seasonal abundances of their prey, and the congregations of fish and squid will become non-existent leading to a mass starvation.  Winter spots, such as the polynyas would be lost due to ice regression and leave Belugas vulnerable to predation.  There has been a shift in prey competition in the Cook Inlet region.   Natives and commercial fishermen have noted a large increase in the amount of Salmon sharks, Spiny dogfish and Northern pike.  The Northern pike is an invasive species that has entered the inlet from surrounding rivers due to floods and the rise in water levels.  As the sea levels rise coastal habitats will be lost destroying the feeding and breeding grounds of the Beluga.  Given the great uncertainties about how Arctic and sub-Arctic ecosystems function and about how they will be affected by climate change, it is difficult to confidently predict impacts of climate change on Beluga prey populations (IUCN 2009).

As the sea levels rise, coastal habitats will be lost destroying the feeding and breeding grounds of the Beluga.  Siltation and erosion have an opposing effect on passageways.  As glaciers melt, sediment is deposited and sandbars are created leaving past migratory routes inaccessible.  Belugas and vessels could be forced to share an overcrowded waterway negatively affecting the Belugas feeding, breeding and migration grounds.

In contrast, as weather patterns become more unpredictable and extreme due to climate change, it is possible that Belugas and other Arctic whales will become more susceptible to ice entrapment.  Such events have always occurred and are assumed to contribute to natural mortality in most Beluga populations. However, it is feared that the frequency and scale of the mortality from ice entrapment will increase as the climate changes (IUCN 2009).

The most pertinent threat to the Beluga today is habitat deterioration in the form of industrial development and water pollution of coastal habitats in which they live.  Some populations are declining principally as a result of pollution.  Belugas in the St Lawrence River Estuary, for example, accumulate so many toxins that deformed calves are prevalent and dead individuals are treated as toxic waste.  The Belugas ingest the pollution through their food sources and this directly impacts their health.  They feed by sifting through sediment to find marine invertebrates.  In the St. Lawrence Estuary this sediment and the species found in it are contaminated with industrial toxins.  For decades the United States used harmful chemicals as pesticides but several of these chemicals were never used in the Arctic or Canada.  The chemicals that pollute the St. Lawrence Estuary were initially developed to resist biodegradation and the residue is still found since the ban of these chemicals.  The chemicals traveled by water and air currents and were deposited in Canadian provinces and the Arctic Ocean.  These chemicals in turn were found in Arctic cod, which is one of the Beluga’s food sources.  The chemicals are soluble in fat and gather in high levels in blubber.  These chemicals cause cancer, malformation, and reproductive problems.

Pollution may become an increasingly significant problem for Belugas with rapid industrialization and urbanization of the Arctic. Many toxic contaminants become concentrated, or biomagnified, as they move up the food chain. Because Belugas and other cetaceans are at or near the top of the food chain and have long life spans, they accumulate relatively high concentrations of certain toxins in their blubber and other organs. These may contribute to a range of health problems in the animals themselves and are also of concern to the people who hunt Belugas for food (IUCN 2009).  The consumption of Beluga whale also raises concerns regarding harmful pollutants.  Several contaminants have been found in Beluga samples including PCBs, toxaphene, DDT and methylmercury.  High levels of mehylmercury have been detected in populations of Beluga whales.  It is believed that diets high in methylmercury can lead to heart disease.  These pollutants affect the Beluga population and thereby affect the health of the Inuit communities.  Some protection from industrial development is being provided at locations where these whales commonly occur but careful monitoring of existing stocks will be needed to secure the future of this attractive cetacean.

Further Reading

1.            Alaska and Inuvialuit Beluga Whale Committee (March, 2003) http://www.state.ak.us/adfg/wildlife/mm/bh.htm

2.            Alvarez-Flores, C. and Heide-Jørgensen, M. P. 2004. Risk Assessment of the beluga (Delphinapterus leucas) harvest in West Greenland. ICES Journal of Marine Science 61: 774-786.

3.            Angliss, R.P. and Lodge, K.L. (2003) Beluga whale (Delphinapterus leucas): Cook Inlet Stock. NOAA, US.

4.            Angliss, R. P. and Outlaw, R. B. 2005. Alaska marine mammal stock assessments. NOAA Technical Memorandum NMFS-AFSC.

5.            Ayotte, P., A. Carrier, N. Ouellet, V. Boiteau, B. Abdous, E. A. L. Sidi, M. Château-Degat, and Ã. Dewailly. 2011; 2011. Relation between methylmercury exposure and plasma paraoxonase activity in Inuit adults from Nunavik. Environmental Health Perspectives 119(8):1077-1077-1083.

6.            Banks, R. C., R. W. McDiarmid, A. L. Gardner, and W. C. Starnes. 2003. Checklist of vertebrates of the United States, the U.S. Territories, and Canada

7.            Banks, R. C., R. W. McDiarmid, and A. L. Gardner. 1987. Checklist of vertebrates of the United States, the U.S. Territories, and Canada. Resource Publication, no. 166. 79

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Life, E., & Matarazzo, N. (2012). Beluga. Retrieved from http://www.eoearth.org/view/article/165117

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