A sentinel species in the North: what belugas can teach us about the world
photo credit: Fisheries and Oceans Canada
Belugas: the Arctic white whales are not only beloved for their amicable nature; they are also wonderful indicators of ecosystem health. That topic is a pretty big part of my research at the University of British Columbia, where I’m working to model mercury contamination in Beaufort Sea beluga whales. Although I’m focusing on mercury concentrations in particular, ecosystem modelling requires an understanding of the species of interest, as well as the ecosystem as a whole. Here, I’ll walk you through belugas as a species, what makes them special to the ecosystem and to humans, and how they can be used in environmental research.
Beluga whales are odontocetes, or toothed whales, that feed on various fish and invertebrates in the ocean. They’re a charismatic and social species that live in groups of up to 100 individuals and communicate via a series of clicks and whistles, a trait that has earned them the nickname the “canary of the sea.” Individuals live an average of 35 to 50 years in the wild and are relatively small, reaching a maximum length of roughly 6 metres, or about two-thirds the length of a school bus.
There are approximately 20 genetically distinct populations or stocks of belugas. Spread across the circumpolar Arctic and the sub-Arctic, they can be found in the waters of Alaska, Canada, Greenland, Norway, and Russia. Most stocks are migratory, moving towards colder waters in the summer in search of more abundant food and returning to the warmer waters in the winter months to breed. The Eastern Beaufort Sea belugas—the stock that I’m studying—spend winter in the Bering Sea but travel 2,500 kilometres to the Beaufort Sea for the summer, which borders northern Alaska, the Yukon, and the Northwest Territories. The St. Lawrence Estuary belugas’ summering grounds extend into the Saguenay River, and in the winter, they’re thought to migrate to Sept-Iles. Meanwhile, the Hudson Bay stock spend their summer in the estuaries of Hudson Bay and migrate north into the open bay in the winter.
Yellow areas are beluga habitat.
photo credit: IUCN
While each beluga population inhabits a different ecosystem and therefore encounters slightly different environmental conditions and prey sources, all stocks play similarly important roles in the ecosystem. As apex predators, they control the prey populations that sit below them in the food web, such as Arctic cod, marine snails, crustaceans, and plankton. They are also an important food source for predators such as orcas, polar bears, and humans, and so support the biomass of the food web above them as well. Belugas are also an important source of nutrients for primary producers and decomposers. When belugas die, their carcasses sink to the bottom of the ocean and serve as food for decomposers; when they’re alive, their fecal matter acts like a pump that recirculates the nutrients that they’ve ingested from fish and zooplankton near the surface to the primary producers below. Belugas are also present in the stories, artwork, spiritual beliefs, tools, and meals of many Arctic Indigenous communities. Though specific traditions and ecological knowledge vary between different Indigenous communities, belugas in general are considered to be culturally, spiritually, and nutritionally important to Indigenous communities and their livelihoods.
Apart from their importance to ecosystems and humans, belugas are also extremely useful to science. They’re a sentinel species because they accumulate pollutants and respond to environmental variability, making them good indicators of ecosystem health. Beluga blubber, behaviour, diet, and contaminants found in their liver and kidneys can indicate the quality of the marine ecosystem as a whole. Scientists can study beluga behaviour, stock size, and migration patterns through aerial surveys; measure concentrations of contaminants like mercury by taking samples from hunted whales; and understand beluga diet by performing stable isotope analysis. More and more, beluga research and monitoring programs are including Indigenous Knowledge in studies, as community observations, experiences, and expertise provide valuable insight into beluga behaviour and health, the ecosystem more broadly, and environmental change. Indeed, various types of environmental change are occurring in the Arctic, including chemical pollution, noise pollution from ships and oil and gas exploration, rising temperatures, melting sea ice, changing food sources, and pathogens.
Through Earth observations, modelling, field measurements, traditional ecological knowledge, and interdisciplinary Arctic research, scientists and communities are working together to understand how belugas are responding to current and future environmental changes. Studying and understanding belugas is important not only for protecting the species. As I’m seeing in my research, belugas can also teach us how climate change is affecting Arctic ecosystems, communities, and public health concerns like environmental mercury concentrations.
