What do belugas die from?
Each year around 15 belugas are found stranded along the shores of the St. Lawrence. What do they die from? An examination of these carcasses has revealed uncommon health problems in this population.
To go through the looking glass
An entire team swings into action as soon as a stranded beluga is reported. The decision whether or not to transport the animal for a more detailed examination is taken at the time of the initial examination on the beach. Between five and ten carcasses are thus transported to the St. Hyacinthe necropsy room every year.
The main causes of death were determined through the analysis of 129 of 264 beluga carcasses discovered along the shores of the St. Lawrence between 1983 and 1999 (n = 129). The study revealed that 27 percent of adult beluga deaths are attributable to cancer, particularly cancer affecting the digestive system. As for the female beluga whales, three cases of mammary gland cancer– a type of cancer never before reported in a cetacean – were revealed, along with three cases of cancer of the ovaries and one case of cancer of the uterus. The level of cancer observed in the St. Lawrence belugas is much higher than levels in Arctic belugas and in all other species of wild mammal. This level is in fact comparable to human levels. Gastro-intestinal and respiratory infections due to parasites are responsible for 22 percent of the deaths of the belugas examined and other infections caused by bacteria, viruses and protozoans caused 17 percent of beluga deaths.
Daniel Martineau, Karin Lemberger, André Dallaire , Philippe Labelle, Pascal Michel et Igor Mikaelian, Faculty of Veterinary Medecine at l’Université de Montréal, Thomas P. Lipscom, Department of Veterinay Pathology, Armed Forces Institute of Pathology.
Department of Fisheries and Oceans Canada, Parks Canada, World Wildlife Fund Canada and SLNIE.
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