What Is Killing the Beluga Whales of the St. Lawrence Estuary?

Beluga Whales of St. Lawrence Estuary

Lawrence River estuary, located in Quebec, Canada, has long been home to the southernmost population of beluga whales, and this isolated population of marine mammals has encountered continual pressure from external sources, such as overhunting and pollution, for most of the 20th century. Although a comprehensive ban on whaling was instituted in the 1950's, marine biologists and other researchers have noted that the expected beluga whale population recovery has failed to materialize, and a number of sound theories have been put forth by qualified scientists to explain the phenomenon. One of the most widely read and recognized of these hypotheses was developed by Canadian researcher Daniel Martineau and a team of colleagues, who studied the corpses of over a hundred beluga during a period of 17 years before determining that the St. Lawrence River estuary "beluga and their environment are contaminated by polycyclic aromatic hydrocarbons (PAHs) produced by the local aluminum smelters" (Martineau et al., 2002). Although the merits of this particular hypothesis have been confirmed by additional studies, I hold that the continuous and steady decline of the beluga whale in the St. Lawrence River estuary, in spite of the species threatened status and worldwide preservation efforts, must be attributable to a more diverse array of external sources than the presence of PAHs alone. I contend that a properly designed study of beluga whale corpses will demonstrate that these animals are succumbing to the effects of a proverbial cocktail of pesticide-based environmental contaminants, in addition to PAHs, and that these effects will be manifested in the form of extremely high rates of cancer development, both among the whales themselves and the human inhabitants of the St. Lawrence River area.

While the study conducted by Martineau and his team was undoubtedly informative and insightful, I contend that focusing solely on the effects of PAHs may result in other carcinogenic factors being neglected or ignored. In order to test for the presence of other carcinogens, including harmful pesticides like DDT and Mirex, it will be necessary to conduct rigorous autopsies on a sample of no less than 120 beluga whales. Samples of organ tissue and blood will be taken from the beluga and tested for noticeable levels of pesticide poisoning, while water and soil quality are also examined for traces of DDT or Mirex. By comparing the samples taken from St. Lawrence River estuary beluga to samples harvested from nominally healthy beluga whales found elsewhere, it will be possible to identify instances of pollution-based tumors, and other evidence of cancer. Because instances of cancer are "normally rare in wildlife, cancers in California sea lions, North Sea flounder and Great Lakes catfish seem to have been triggered or accelerated by environmental contaminants" (Gammon, 2009), and the heavy agricultural use by humans living in these habitats suggests a connection between the heavy use of pesticides and cancer rates in marine wildlife. This experiment represents a systems-based approach because I intend to index all autopsy findings by the age, sex, and size of the animal, in an effort to determine if sufficient numbers of beluga whales are living to reach breeding age. If cancers caused by pesticide absorption are causing beluga to die before they are able to breed, this phenomenon would further explain the overall population's inability to fully recover.