Beluga whales have traditionally been hunted for their blubber for many centuries, but only with the advent of commercial whaling did the harvest become unsustainable (6) (9). This species is particularly vulnerable to such exploitation, due to its high fidelity for certain migratory routes (3).
However, perhaps the most pertinent threat to the beluga whale today is habitat deterioration in the form of industrial development and pollution of coastal habitats (3). Some beluga whale populations are declining principally as a result of pollution. Beluga whales in the St Lawrence River Estuary, for example, accumulate so many toxins that deformed calves are now prevalent and dead individuals are treated as toxic waste (10).
A further identified threat to the beluga whale is global climate change. While this species is not thought to be directly threatened by changes in weather patterns or global warming, reductions in sea ice cover will provid access to the Arctic for ships and other vessels, which were previously absent from the region. Formerly pristine areas that have long served as refuges for the beluga whale will become more navigable, with numbers of vessel sailing through the Arctic for gas and oil exploration, commercial shipping and fishing increasing. With the increase in ship traffic, ship strikes are likely to become an increasingly significant cause of beluga whale injury and death (11).
In addition, beluga whales detect and respond to the presence of large ships over great distances of up to 50 kilometres. Industrial noise, for example from ships, seismic surveys and offshore drilling, likely disrupts beluga whale behaviour and may impair their ability to communicate and forage efficiently. Industrialisation and urbanisation of the Arctic is also bound to exacerbate the problem of pollution (11).
Climate change is also likely to lead to a loss of sea ice and increased ocean temperatures. This may affect the distribution, composition and productivity of beluga whale prey species, affecting the beluga whale’s ability to find prey. Furthermore, as weather patterns become more unpredictable and extreme, it is possible that the beluga whale will become more susceptible to ice entrapment. Such unfortunate events have always occurred, but it is feared that the frequency and scale of the mortality from ice entrapment will increase as the climate changes (11).