The beluga whale, often called the “white whale” or the “canary of the sea,” is a toothed cetacean residing in the Arctic and sub-Arctic. Its white coloration, flexible neck, and lack of a dorsal fin are adaptations for navigating the icy marine environment. Belugas are social animals, forming large pods that rely on vocalizations for communication and echolocation. This species spends its life in the shallow coastal waters, estuaries, and deeper ocean regions across the circumpolar north, where its presence shapes the ecosystem.
Belugas as Regulators of the Marine Food Web
Beluga whales occupy a mid-to-high trophic position in their ecosystem, functioning as predators that structure the Arctic food web. Their dietary habits, which shift based on season and location, involve consuming smaller organisms, thereby exerting a top-down control on prey populations. Belugas hunt fish, including Arctic cod, salmon, and herring, alongside invertebrates such as shrimp, squid, and octopus.
By consuming these animals, belugas prevent the overpopulation of specific prey items, which maintains biodiversity across the lower trophic levels. Their predation ensures that no single species monopolizes the primary food sources, allowing for a more stable community structure. This regulatory effect helps maintain the food web in the face of environmental fluctuations.
Indicators of Arctic Environmental Health
Belugas are recognized as “sentinel species,” serving as biological monitors for the health of the Arctic marine environment. Several characteristics make them susceptible to accumulating contaminants, offering a direct measure of pollution levels in their habitat. As long-lived mammals, with lifespans extending up to 80 years, belugas have extended periods during which toxins can build up in their bodies.
The blubber layer that insulates the beluga also acts as a reservoir for fat-soluble pollutants like polychlorinated biphenyls (PCBs) and heavy metals such as mercury. Monitoring the contaminant load in beluga tissues provides researchers with data on the bioaccumulation of toxins transported into the Arctic. Changes in their body condition, migration timing, and reproductive success are observed as responses to shifting sea ice conditions and noise pollution, which makes them early warning systems for climate change and human activity.
Contribution to Oceanic Nutrient Cycling
Beluga whales participate in the biogeochemical cycles of the ocean, moving and redistributing nutrients across different water depths and regions. This process, referred to as the “whale pump,” involves the vertical transport of elements like nitrogen and phosphorus. Belugas dive to forage for prey and then return to the surface, where they excrete nutrient-rich fecal plumes.
This waste releases dissolved nutrients into the sunlit surface layer, or euphotic zone, stimulating the growth of phytoplankton. Phytoplankton are microscopic organisms that form the base of the marine food web and capture atmospheric carbon dioxide. Upon the death of a beluga, its body sinks to the deep-sea floor, creating a “whale fall” that delivers organic carbon and nutrients. This supports deep-sea scavengers and microbes, enriching the benthic ecosystem.