|Scientific Name:||Delphinapterus leucas|
|Species Authority:||(Pallas, 1776)|
|Infra-specific Taxa Assessed:|
|Taxonomic Notes:||Specimens that appear to be hybrids between Narwhals and Belugas have been described from nature (Heide-Jørgensen and Reeves 1993). An alternative common name is White Whale.|
|Red List Category & Criteria:||Near Threatened ver 3.1|
|Assessor/s:||Jefferson, T.A., Karkzmarski, L., Laidre, K., O’Corry-Crowe, G., Reeves, R., Rojas-Bracho, L., Secchi, E., Slooten, E., Smith, B.D., Wang, J.Y. & Zhou, K.|
|Reviewer/s:||Brownell Jr., R.L. & Cooke, J.|
At the global level the species does not qualify for a threatened status under any of the criteria although there is substantial uncertainty about numbers and trends for at least some large parts of the range, especially in the Russian Arctic. Given that uncertainty, and the fact that cessation of national and international, taxon-specific conservation programs that currently monitor and manage hunting could result in the Beluga’s qualifying for threatened status (under criterion A3) within five years, the species should be listed as Near Threatened. The Beluga whale is unquestionably a conservation-dependent species.
The species was assessed previously (1996) as Vulnerable (VU A1abd). The main reason for the change to Near Threatened is that the decline criterion for Vulnerable is not met for some of the largest subpopulations, and they have a disproportionate effect on the assessment of the species as a whole. Also, estimates of current population size for several of the larger stocks are substantially higher than previous estimates (due to better survey methods and not necessarily because of increases in numbers).
Across the global range of Belugas, subpopulations are subject to differing levels of threat and warrant individual assessment. Some subpopulations clearly qualify for threatened status and only one of these – the Cook Inlet subpopulation – has been assessed thus far (as CR) (Lowry et al. 2006). Those other potentially threatened subpopulations (e.g. West Greenland, eastern Hudson Bay, St. Lawrence River, Ungava Bay) that are well-defined and well-studied should be assessed separately as soon as feasible.
|Range Description:||Beluga whales are distributed in high latitudes of the Northern Hemisphere from the west coast of Greenland westwards to Svalbard (Stewart and Stewart 1989; O'Corry-Crowe 2002). Records from the Sea of Japan and Baltic Sea are considered extralimital, but resident populations occur in cold temperate latitudes in Cook Inlet (Alaska, US) and the St. Lawrence River system (Canada). Satellite telemetry, genetic studies, and organochlorine analyses show belugas have strong matrilineally driven seasonal site fidelity to fjords and estuaries for summering and they migrate to separate wintering grounds (O’Corry-Crowe et al. 1997, Richard et al. 2001, de March et al. 2002, Innes et al. 2002, O’Corry-Crowe et al. 2002, Palsbøll et al. 2002).
The map shows where the species may occur based on oceanography. The species has not been recorded for all the states within the hypothetical range as shown on the map. States for which confirmed records of the species exist are included in the list of native range states.
Native:Canada; Greenland; Russian Federation; Svalbard and Jan Mayen; United States
Vagrant:Belgium; Denmark; Faroe Islands; France; Germany; Iceland; Ireland; Japan; Netherlands; Norway; Sweden; United Kingdom
|FAO Marine Fishing Areas:||
Arctic Sea; Atlantic – northeast; Atlantic – northwest; Pacific – northeast; Pacific – northwest
|Range Map:||Click here to open the map viewer and explore range.|
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. While good abundance estimates are available for some Beluga subpopulations/stocks, the sizes of others are virtually unknown. Total numbers worldwide are well above 150,000 animals, with many portions of the range unsurveyed. 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:
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.
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 colouration. 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, 1/07).
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 stock of belugas at 1,200, 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.
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).
Cumberland Sound: This stock numbers about 1,500 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 1,300 along the southern Hudson Bay coast (Richard 1991).
East Hudson Bay: Belugas in Eastern Hudson Bay have declined from 4,200 (SE 300) in 1985 to 3,100 (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 900–1,000 individuals. There is no evidence of a significant trend in abundance since 1988 (COSEWIC 2004).
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 behaviour. It includes whales that move to West Greenland during the winter.
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 over-harvesting (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.
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).
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 animals, belugas from 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: (1) southern Barents and White seas, (2) southern Barents and Kara seas, (3) coastal waters of the Kara Sea, and (4) western portion of the Laptev Sea. They may share wintering grounds to some extent. Surveys have not yet been conducted in the Barents and Kara seas and the number of Belugas inhabiting these regions is unknown. 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 and Ecology:||
Belugas are relatively well-studied as a result of carcass sampling in association with hunting, along with a considerable amount of satellite-linked radio-tracking (Richard et al. 1998a,b; Richard et al. 2001; Lydersen et al. 2001; Heide-Jørgensen et al. 2003a; Hobbs et al. 2005).
Belugas occur seasonally (mainly in summer) in coastal waters as shallow as 1–3 m deep but also in deep offshore waters (800 m). They typically enter estuaries and sometimes move upstream into rivers; there are records of individuals or small groups ranging hundreds of kilometers from the sea. They occupy estuaries, continental shelf and slope waters, and deep ocean basins in conditions of open water, loose ice, and heavy pack ice. Belugas generally prefer to overwinter in shallow or coastal areas, usually with light or highly moveable ice cover (Barber et al. 2001, Richard et al. 2001, Suydam et al. 2001, Heide-Jørgensen et al. 2003a) and may occur as fully Arctic populations (Richard et al. 1998b, Richard et al. 2001, Suydam et al. 2001) or sub-Arctic populations (Hobbs et al. 2005).
Some Belugas undertake large-scale annual migrations between summering and wintering sites, while others remain in the same area year-round, shifting offshore only when excluded from coastal habitat by fast-ice formation (Hobbs et al. 2005). Large numbers of migratory Belugas occur along the northwestern and northern Alaskan coast, in the Canadian high Arctic, and in western Hudson Bay. At certain times of the year, those whales migrate thousands of kilometers, in some cases as far as 80oN into dense pack ice (Suydam et al. 2001) or thousands of kilometers into the North Water polynya or to the pack ice off West Greenland (Richard et al. 1998a,b; Richard et al. 2001; Heide-Jørgensen et al. 2003a). Non-migratory belugas that generally make seasonal shifts in distribution of less than a few hundred kilometers are found in Cook Inlet, Cumberland Sound, Svalbard, and the Gulf of St. Lawrence (Lydersen et al. 2001; Kingsley 2002; Hobbs et al. 2005).
While the general features of Beluga whale habitat can be described for the relatively well-studied populations, the importance of those features is not well understood (Laidre et al. in press). For example, the summer occupation of nearshore/estuarine waters has been ascribed alternatively to feeding (Seaman et al. 1982), to warm water providing a thermal advantage to neonates (Sergeant and Brodie 1969), and to the presence of fresh water and coarse substrates facilitating skin shedding during molt (St. Aubin et al. 1990, Frost et al. 1993). The relative importance of each of those factors likely varies based on the environmental conditions (e.g., water temperatures and prey availability) specific to each of the summering areas (Frost and Lowry 1990a). Similarly, it is unclear why belugas sometimes move into deep, ice-covered waters. One potential reason would be to avoid Killer Whale (Orcinus orca) predation (Frost et al. 1992). However, the movements into the ice appear excessive for what would be needed to avoid killer whales (Suydam et al. 2001) and actually could expose belugas to predation by Polar Bears (Ursus maritimus) (Lowry et al. 1987a) as well as increase the risk of entrapment in the ice. It is possible belugas move into ice-covered offshore regions for feeding, primarily on Arctic Cod (Boreogadus saida), but few data are available to test this hypothesis. Similarly, the associations of belugas with features such as the continental shelf break (Moore 2000) may be related to oceanographic processes that produce good feeding conditions (Laidre et al. in press).
Dives may last up to 25 min. and can reach depths of 800 m. The Beluga has a diverse diet, which varies greatly from area to area. Although various species of fish are considered to be the primary prey items (including salmon, herring, and Arctic Cod), Belugas also feed on a wide variety of molluscs (such as squid and octopus) and benthic crustaceans (shrimps and crabs). Polar Bears and Killer Whales are known predators of belugas throughout their Arctic range (Frost et al. 1992).
Hunting for human consumption is the biggest known threat to belugas across certain portions of their range. The most immediate concerns relate to continuing harvests from small and depleted subpopulations (IWC 2000). The strong philopatry of belugas, which causes them to return to the same estuaries year after year, makes them highly vulnerable to overexploitation. This behavioural trait is undoubtedly the most important natural factor that has led to the extirpation of Belugas from some parts of their range by a combination of commercial and subsistence hunting (e.g. in southwestern Greenland and some river mouths in Ungava Bay, Canada).
Known or potential threats include a variety of human activities in addition to hunting: oil and gas development, expansion of fisheries (with possible implications for bycatch and resource depletion), hydroelectric development (in Hudson Bay), and industrial and urban pollution. Climate change will likely increase the scale and distribution of these activities. Hydroelectric development may affect belugas because of their dependence on estuarine conditions. Areas such as the McKenzie Delta and West Greenland are subject to oil exploration, which often includes seismic surveys, offshore drilling, and artificial island construction. These activities are undertaken in the summer months in the same areas occupied by belugas at this time of year. In a study of responses of belugas to ice-breaking ships, the Belugas typically moved rapidly along ice edges away from approaching ships and showed strong avoidance reactions to approaching ships at distances of 35–50 km (Finley et al. 1990).
Climate change is another potential threat. Belugas may experience climate-induced geographic shifts or altered reproductive success due to persistent changes in extent of sea ice (Tynan and DeMaster, 1997, Laidre et al in press). Belugas are also susceptible to savssats or ice entrapments when sea ice conditions change rapidly.
Threats from contaminants are of concern in some areas. Studies of the small, geographically isolated subpopulation in the St. Lawrence River have found that concentrations of both total PCBs and chlorinated PCB congeners are much higher in these belugas than in Arctic belugas. Some scientists believe that the increased occurrence of opportunistic bacterial infections, parasitic infestation, gastric ulcers and other disorders in St. Lawrence belugas is evidence of a link between immune system dysfunction and PCB exposure (Martineau et al., 1994).
To summarize, in some parts of the species’ range, particularly in Canada and Greenland, intensive hunting represents an ongoing major threat, and in a few instances this is compounded by the less direct and less easily quantified threats (realized and potential) 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), climate change (including secondary effects from opening of Arctic and sub-Arctic waters to year-round ship traffic, oil an gas development, commercial fishing), and possibly incidental catch in fisheries (e.g. St. Lawrence estuary).
Although the Beluga was hunted intensively on a commercial basis in many parts of its range during the 20th century, the only known direct removals at present are for food (subsistence use) and the aquarium trade (there is a limited live-capture fishery in Russia). A regional management body, the Joint Committee on Narwhal and Beluga/North Atlantic Marine Mammal Commission (JCNB/NAMMCO), exists in Canada and Greenland with the expectation that it will ensure the conservation of Belugas. This body sets or recommends catch limits for Beluga populations within member countries. Catch levels from subpopulations range anywhere from <10 to a few hundred animals per year. Removals from some subpopulations/stocks are considered sustainable, however, there is concern and evidence that removals from other subpopulations/stocks are not (e.g. Eastern Hudson Bay and West Greenland) (Alvarez and Heide-Jørgensen 2004, COSEWIC 2004, NAMMCO/JCNB 2005).
It is listed on CITES Appendix II.
|Citation:||Jefferson, T.A., Karkzmarski, L., Laidre, K., O’Corry-Crowe, G., Reeves, R., Rojas-Bracho, L., Secchi, E., Slooten, E., Smith, B.D., Wang, J.Y. & Zhou, K. 2012. Delphinapterus leucas. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 24 May 2013.|
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