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


  • Carcass of beluga whale ashore
  • Photo credit : © GREMM

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.

In short

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.

Project collaborators

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.

Scientific papers

Béland, P. 1996. The beluga whales of the St. Lawrence River. Scientific American May 1996: 74-81.

Béland, P., S. DeGuise, C. Girard, A. Lagacé, D. Martineau, R. Michaud, D. C. G. Muir, R. J. Norstrom, É. Pelletier, S. Ray et L. R. Shugart. 1993. Toxic compounds and health and reproductive effects in St.Lawrence beluga whales. J. Great Lakes Res. 19(4): 766-775.

Béland, P., S. DeGuise et R. Plante. 1992. Toxicologie et pathologie des mammifères marins du St-Laurent. Rapport pour le Fonds pour la toxicologie faunique du Fonds mondial pour la nature, mai 1992.

Jarman, W. M., R. J. Norstrom, D. C. G. Muir, B. Rosenberg, M. Simon et R. W. Baird. 1996. Levels of organochlorine compounds, including PCDDS and PCDFS, in the blubber of cetaceans from the west coast of North America. Marine Pollution Bulletin 32(5): 426-436.

Martineau D., K. Lemberger, A. Dallaire, P. Labelle, T. P. Lipscomb, P. Michel, I. Mikaelian. 2002. Cancer in wildlife, a case study: beluga from the St. Lawrence estuary, Québec, Canada. Environmental Health Perspectives. 110(3): 1-7.

Martineau, D., S. DeGuise, M. Fournier, L. Shugart, C. Girard, A. Lagacé et P. Béland. 1994. Pathology and toxicology of beluga whales from the St. Lawrence Estuary, Quebec, Canada. Past, present and future. Sci. Total Environ. 154: 201-115.

Muir, D. C. G., C. A. Ford, B. Rosenberg, R. J. Norstrom, M. Simon et P. Béland. 1996. Persistent organochlorines in beluga whales (Delphinapterus leucas) from the St. Lawrence River estuary. I. Concentrations and patterns of specific PCBs, chlorinated pesticides and polychlorinated dibenzo-p-dioxines and -dibenzofurans. Environmental Pollution 93 (2): 219-234.

Muir, D. C. G., C. A. Ford, R. E. A. Stewart, T. G. Smith, R. F. Addison, M. E. Zinck et P. Béland. 1990. Organochlorine contaminants in belugas, Delphinapterus leucas, from Canadian waters.Can. Bull. Fish. Aquat. Sci. 224: 165-190.

Muir, D. C. G., K. Koczanski, R. Rosenberg et P. Béland. 1996. Persistent organochlorines in beluga whales (Delphinapterus leucas) from the St. Lawrence River estuary. II. Temporal trends, 1982-1994. Environmental Pollution 93 (2): 235-245.

Norstrom, R. J., D. C. G. Muir, C. A. Ford, M. Simon, C. R. Macdonald et P. Béland. 1992. Indications of P450 monooxygenase activities in beluga (Delphinapterus leucas) and narwhal (Monodon monoceros) from patterns of PCB’ PCDD and PCDF accumulation. Marine Environmental Research 34: 267-272.