Beluga whale (Delphinapterus leucas) COSEWIC assessment and status report: chapter 2
The beluga, Delphinapterus leucas, is a medium-sized toothed whale, which becomes completely white when it reaches sexual maturity around seven years of age. Adult males attain a length of 4.5 meters and females 3.5 meters. Both are similar in appearance. Young are born a dark grey and gradually become paler as they mature.
Belugas are also known as white whale, béluga in French, and qilalugaq or siqsuaq in the Inuktitutt, Inuvialuktun and Inupiat dialects.
Currently available evidence supports continuing to divide the Canadian belugas into seven populations, based on largely disjunct summer distributions and genetic differences: (1) the St. Lawrence Estuary population occupying the area of the estuary centered around the Saguenay River mouth; (2) the Ungava Bay population occupying the whole of Ungava Bay in the summer; (3) the Eastern Hudson Bay population occupying the area from Kuujjuaraapik to Inukjuak, in the area of the Little Whale and Nastapoka Rivers during the summer months; (4) the Western Hudson Bay population occupying the areas of the Seal, Nelson and Churchill Rivers and further north to Southampton Island and Roes Welcome Sound during the summer and early autumn months; (5) the Eastern High Arctic – Baffin Bay population spending its summer in the Lancaster Sound, Barrow Strait, Prince Regent Inlet and Peel Sound areas of the Canadian high Arctic (6) the Cumberland Sound population which seems restricted to the Cumberland Sound area and concentrates in Clearwater Fiord during July and August; (7) the Eastern Beaufort Sea population occupying the Delta of the Mackenzie River and into the Amundsen Gulf and as far north as Viscount Melville Sound during late summer.
Migrations of all the populations occur from overwintering areas in the areas of open water to their spring and summer calving and feeding areas, which are usually river estuaries.
Population Sizes and Trends
There are large differences in both the extent of the range and size of the seven beluga populations. (1) The St. Lawrence population is estimated to be in the order of 900-1000 individuals. There is no evidence of a significant trend in abundance indices since 1988. (2) The Ungava Bay population is too small to estimate. It might have been extirpated. (3) The Eastern Hudson Bay population is declining rapidly in size and numbers around 2000 individuals. Recent harvest levels could cause this population to be extirpated in less than 10 years. (4) The Western Hudson Bay population has a minimum of about 23 000 animals, but is the subject of a substantial hunt. (5) The Eastern High Arctic – Baffin Bay population is estimated to be in the order of 20 000 animals. It might consist of two distinct populations: the West Greenland population numbering around 5 000 belugas, which is heavily exploited, and the North Water population, which numbers approximately 15 000 belugas, and is only lightly hunted. (6) The Cumberland Sound population numbers about 1500 animals and is thought to have increased since the 1980s. (7) An estimate of the Eastern Beaufort Sea population of 39 000 animals is considered conservative and this population is exploited at a level well below the sustainable yield.
Belugas spend the summer in coastal and offshore areas. Their distribution is centred on certain river estuaries, which they visit shortly after ice break-up and where they moult. They frequent these areas occasionally throughout the summer months. In the autumn they begin migrating to other locations, including certain deep-water areas, where they may feed intensively. They then continue to move to areas where pack-ice is of about 4/10-8/10 cover, in which they spend the winter.
Belugas have mean lifespans in the range of 15 to 30 years, although they may live beyond age 40, and are sexually mature at the ages of 5-7 years. Scientific evidence suggests that adults are capable of giving birth, on the average, every 3 years. They feed on a variety of fish and invertebrates. Little is known of their mating behaviour as this occurs in the winter offshore areas. Polar bears, killer whales and Inuit hunters are their main predators. Belugas occupy the level above fish, but below bears, in the Arctic trophic pyramid.
Limiting Factors and Threats
Sources of natural mortality include killer whales and polar bears, which often prey on belugas when they become entrapped in ice. Belugas are made vulnerable to both bear and human predation by their habit of returning to specific rivers and continuing to use these sites in spite of intense hunting pressure. Belugas in the St. Lawrence are further stressed by disturbance, pollution and loss of habitat.
Existing Protection or Other Status Designations
The hunting of belugas of the St. Lawrence Estuary has been prohibited since 1979 under the Fisheries Act. The St. Lawrence Beluga Recovery Plan has focused research and management efforts on this population. Under the Quebec Endangered Species Act, this population has been classified as Endangered. The St. Lawrence belugas have also received special protection from harassment under the law creating the Saguenay St. Lawrence Marine Park. The Ungava and Eastern Hudson Bay belugas are the subject of quotas, and closed hunting seasons in certain areas under a co-management plan between Nunavik and Department of Fisheries and Oceans Canada in an effort to remedy the critical status of these populations. The Cumberland Sound population is co-managed by the Pangnirtung Hunters and Trappers Association, the Department of Fisheries and Oceans Canada, and the Nunavut Wildlife Management Board with a current (2003) annual quota of 41 beluga whales. Community quotas also exist for Nunavik communities, and recommendations have been made to drastically reduce the harvests of belugas in the possibly separate West Greenland population. The Eastern Beaufort Sea population is co-managed by Hunter and Trappers Committees, the Inuvialuit Game Council, the Department of Fisheries and Oceans and the Fisheries Joint Management Committee.
The St. Lawrence belugas are the subject of ongoing research and discussions in an effort to protect the population and its habitat from various negative anthropogenic factors.
For both the Cumberland Sound and the St. Lawrence populations, efforts of management appear to have helped these populations to stabilize their numbers.
Report a problem or mistake on this page
- Date modified: