Beluga

In the St. Lawrence

Its annual range extends from the St. Lawrence Estuary to the Gulf of St. Lawrence and into the Saguenay Fjord. The population is estimated at around 900 individuals. It frequents coastal waters with strong currents such as river mouths. Cows accompanied by their calves prefer protected bays. In winter, they seem to favour open ice with 70-90% cover.

Migration

It is the only year-round resident cetacean of the St. Lawrence, where it feeds, reproduces and calves. However, migratory movements are observed between the downstream and upstream portions of its range. In summer, the population is concentrated in the Estuary between Île aux Coudres, Forestville (Upper North Shore) and Île du Bic (south shore) as well as the Saguenay Fjord. In winter, the population moves into the downstream sector of the Estuary (between Forestville and Pointe des Monts) and into the northern parts of the Gulf. In spring, it ranges from the Gaspé Peninsula to Île aux Coudres. The formation of herds numbering up to 100 or more individuals in the spring and autumn might be attributable to these migratory movements.

In the world

St. Lawrence belugas are isolated from other populations of the species residing in the Arctic and distinct from a genetic perspective. It is the southernmost population, frequenting areas in close proximity to human activities and heavy industry. Elsewhere in the world, belugas are found only in the Northern Hemisphere, in seas, estuaries and rivers of circumpolar regions between the 50^th and 80^th parallels.

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) designated the St. Lawrence beluga population “endangered” in 2014. The population had been listed as “threatened” in 2004. COSEWIC experts, who undertake a species status assessment every ten years, have evaluated that this small population is now facing a considerably higher risk of extinction. In 2013, St. Lawrence beluga specialists issued a Science Advisory Report in which they established that this population is declining and that the rise in newborn mortalities that has been observed in recent years might accelerate this decline.

Only about 900 belugas are believed to remain in the St. Lawrence. Major factors identified as threats or limitations to the recovery of the population include contamination from chemical products; loss and degradation of its habitats; reduction in the abundance, availability and quality of prey; as well as disturbance. Through their cumulative impacts, which are further aggravated by climate change, these threats exert an even more serious pressure on the population. Furthermore, the small size of the population, its restricted range, low genetic diversity and isolation from other beluga populations in the Arctic are considered to be risk factors.

The International Union for Conservation of Nature (IUCN) has listed global beluga populations as “near threatened”. In Quebec, the St. Lawrence population has been “threatened” since 2000 on the List of threatened or vulnerable species in Quebec under the Act Respecting Threatened or Vulnerable Species.

Feeding

A beluga uses its teeth to bite into its prey, which it swallows whole. Suction is the main means of capturing prey that it hunts near the seabed. It feeds on bottom-dwelling fish (capelin, herring, smelt, sand lance), eels and invertebrates (nereid worms, squid, octopuses, crustaceans). But it can also hunt in a water column and near the surface while swimming or treading against the current. Thanks to an intimate knowledge of its environment and highly efficient hunting strategies, it spends little time searching for food, dedicating its time instead to travelling, resting and engaging in social activities. Learning such strategies requires cooperation between individuals as well as a more prolonged mother-to-calf transfer than in baleen whales.

On the surface

Being the slow swimmers they are, belugas are happy to use the currents to travel. They perform 2 or 3 breathing sequences and rarely raise their tail out of the water when diving. In compact groups, individuals sometimes show themselves to be highly dynamic: they frolic about, rolling onto their sides and partially jutting out of the water, sticking their heads out and slapping the water surface with their tails. These behaviours may be related to feeding, juvenile play, or sexual behaviour, their pink penises sometimes being visible during these antics.

Diving

Studies conducted in the Arctic show that belugas spend between 40 and 60% of their time below the surface. Dives can last up to 15 minutes and reach depths of up to 800 m, with 70% exceeding 40 m. Of these, 80% include a prolonged foray near the seabed. Data on the diving behaviour of the St. Lawrence beluga are currently under analysis.

Social

The beluga is a gregarious animal, living in pairs and groups of 3 to several dozen individuals or clans, governed according to sex- or age-based segregation. During the summer months, the largest herds are typically composed of cows accompanied by newborns and juveniles. Bulls tend to form smaller groups. In the St. Lawrence, these clans are faithful to their territories.

Vocalization

Belugas have an extensive vocal repertoire consisting of whistles, chattering, squeals and grunts, earning them the nickname “canaries of the sea”. These vocal skills might be an important adaptation to life near the sea ice where ambient noise is omnipresent. This repertoire includes two categories of sounds: whistles and pulsing sounds. The role of these vocalizations as they relate to social behaviour and communication is still poorly understood. Specific sounds known as “calls” are emitted in situations of disturbance to maintain the cohesion of the pod, and particularly the contact between mothers and their calves. For navigating and finding prey, belugas possess a high performance echolocation system comparable to radar.

Females reach sexual maturity between 8 and 14 years of age, and males between 16 and 18. Mating takes place between April and June. Gestation lasts 14 months. Calving runs from June to September. Nursing lasts between 20 and 30 months.