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The global population of beluga today stands at about 100,000. Although this number is much greater than that of other cetaceans, it is much smaller than historical populations before decades of over-hunting. There are estimated to be 40,000 individuals in the Beaufort Sea, 25,045 in Hudson Bay, 18,500 in the Bering Sea and 28,008 in the Canadian Low Arctic. The population in the St. Lawrence estuary is estimated to be around 1000.[1] They are considered an excellent sentinel species and indicator of the health of, and changes in, the environment. This is as they are long lived, on top of the food web, with large amounts of fat and blubber, relatively well studied for a cetacean, and still somewhat common.
The beluga's natural predators are polar bears, who hunt when the whales become encircled by ice during winter. In these cases many miles of ice separate groups of Belugas from the open ocean, and as a result they are unable to leave until the ice melts in spring. During this period belugas do not offer much resistance to bear attacks due to their low energy reserves.
Because beluga congregate in river estuaries, human-caused pollution is proving to be a significant danger to their health. Incidents of cancer have been reported to be rising as a result of the St. Lawrence River pollution. The bodies of the Beluga residents in this area contain so many contaminants that their carcasses are treated as toxic waste. Reproductive pathology has been discovered in the population here and many suspect organochlorines to be responsible. Levels between 240 ppm and 800 ppm of PCBs have been found, with males typically having higher levels.[2] It is not known what the long-term effects of this pollution will be on the affected populations.
Erysipelothrix rhusiopathiae gram positive/variable bacilli, likely from contaminated fish in the diet, can endanger the beluga causing anorexia, dermal plaques, and lesions. This may lead to death if not diagnosed early and treated with antibiotics. Cetaceans seem quite vulnerable to pneumonia, and various species of the aerobic actinomycete Nocardia, likely more problematic when anything causes more soil or dust to become airborne, (spreading the organisms to the water or air the belugas breath), can be worrisome and can lead to death.
Belugas were amongst the first whale species to be brought into captivity. The first beluga was shown at Barnum's Museum in New York in 1861. Today it remains one of the few whale species kept at aquaria and sea life parks across North America, Europe and Asia. Their popularity there with visitors reflects their attractive color, and their range of facial expressions. While most cetacean "smiles" are fixed, the extra movement afforded by the beluga's unfused cervical vertebrae allows a greater range of expression. Most beluga found in aquariums are caught in the wild, though captive breeding programs have enjoyed some success.
Indirect human disturbance may also be a threat to the species. While some populations have come to tolerate small boats, others have been known to actively try to avoid ships. Whale-watching beluga has become a huge and booming activity in the St. Lawrence and Churchill River areas.
Because of their predictable migration pattern and high concentrations, beluga have been hunted by indigenous Arctic peoples for centuries. In many areas a pattern of hunting, believed to be sustainable, continues to this day. However, in other areas, such as the Cook Inlet, Ungava Bay, and off west Greenland, previous commercial catches (now banned under the general moratorium on whaling) left the populations in great peril. Indigenous whaling continues in these areas, and some populations continue to decline. These areas are the subject of intensive dialogue between Inuit communities and national governments aiming to create a sustainable hunt and are the reason that the beluga has been listed as vulnerable on the IUCN Red List of Threatened Species since 1995.
Both the United States Navy and the Soviet Navy have used belugas in anti-mining operations in Arctic waters.
