Beluga
Delphinapterus leucas

The White Coat and Its Variations by Age

Newborns are born dark gray, sometimes slightly brownish. The coat lightens progressively: pale gray in juveniles, then cream white, then pure white in adults, generally between 7 and 12 years old (GREMM, baleinesendirect.org). This progression is a reliable age criterion in the field, especially in mixed groups.

Absence of Dorsal Fin and Dorsal Ridge

The beluga is one of the few cetaceans without a dorsal fin. Instead, it has a low, rough dorsal ridge, more pronounced in adults. This adaptation reduces heat loss and facilitates movement under the ice pack, where a protruding fin would be an obstacle. At sea, this flat silhouette is immediately distinctive.

The Melon: Shape, Mobility, and What It Reveals

The beluga's frontal melon is particularly developed and, above all, deformable. The beluga can contract or inflate it using specialized facial muscles. This mobility is not cosmetic: it plays a direct role in modulating acoustic signals. No other cetacean of comparable size exhibits this facial plasticity.

Blow, Surface Posture, and Characteristic Swim

The blow is short and unimpressive, often invisible in light winds. The beluga swims slowly at the surface with undulating tail movements. It is capable of swimming in reverse, a rare ability among cetaceans, linked to the mobility of its unfused cervical vertebrae. To avoid confusion with the narwhal (Monodon monoceros), another Arctic Monodontid: the adult narwhal has a mottled skin and, in males, a long spiral tusk absent in the beluga.

Morphology Adapted to Icy Waters: Blubber, Mobile Cervical Vertebrae

The beluga has a layer of subcutaneous fat (blubber) that can reach 15 cm thick, one of the highest proportions among odontocetes. This thermal reserve is essential in waters near 0 °C. Another major anatomical feature: its cervical vertebrae are not fused, unlike nearly all other cetaceans. It can thus turn its head laterally, giving it unmatched hunting and navigation flexibility under the ice within the Cetacean order.

Diving: Depth, Duration, and Respiratory Capabilities

Belugas reach depths of 700 to 800 meters and can hold their breath for up to 25 minutes (Castellini, 2012). These performances allow them to exploit benthic resources inaccessible to most dolphins of comparable size. They surface regularly to breathe through cracks in the ice pack, which they locate by echolocation.

Diet and Echolocation Hunting Strategies

The diet is opportunistic and varies by season and region: fish (capelin, Arctic cod, salmon), cephalopods, crustaceans, and polychaete worms. Hunting relies on precise echolocation, produced via the melon and nasal system. Some groups use cooperative strategies to encircle fish schools, a behavior documented in the St. Lawrence estuary (GREMM).

Longevity, Sexual Maturity, and Reproductive Cycle

The documented maximum longevity is about 60 years. Sexual maturity occurs between 8 and 14 years depending on individuals and populations. Gestation lasts 14 to 15 months, and females nurse their calf for an average of 2 years. The interval between births is therefore long, making populations particularly vulnerable to any excess mortality.

The nickname "sea canary" is not a casual metaphor: it reflects a biological reality documented since the first underwater acoustic studies in the 1940s. The beluga produces an exceptionally rich vocal repertoire among cetaceans: tonal whistles, echolocation clicks, chirps, impulsive sounds, grunts. These vocalizations are audible from the surface, even from a ship's hull, which is rare.

The melon plays a central role in producing and modulating these sounds. It focuses and directs the acoustic signals emitted by the nasal system. Its deformability allows the beluga to adjust the directivity of its emissions in real time, a level of acoustic control unmatched in similarly sized odontocetes.

At the social level, vocalizations ensure group cohesion (called pods), hunting coordination, mother-calf communication, and probably individual identification. Belugas live in structured groups, sometimes numbering hundreds during summer gatherings in estuaries. Acoustic communication is the glue of this organization.

This sound dependence makes the beluga particularly vulnerable to underwater noise pollution. Maritime traffic, military sonars, offshore extraction work, and seismic survey activities generate noise levels that mask or disrupt vital signals. In the St. Lawrence estuary, intense commercial traffic is identified as one of the direct threats to the resident population (Pettis et al., NOAA report). Reducing anthropogenic noise is thus a conservation measure as important as limiting approaches.

The IUCN classifies the beluga as "Least Concern" globally (IUCN, 2017), with a global estimate of 150,000 to 200,000 individuals. This aggregate figure masks highly contrasting local situations across sub-populations.

St. Lawrence Estuary Population: Critical Status and Recovery Program

This is the most studied and threatened sub-population in North America. Estimated at about 900 individuals (GREMM, recent data), it is designated "endangered" by the Committee on the Status of Endangered Wildlife in Canada (COSEPAC). Genetically distinct from Arctic populations, it receives no external migratory input. Chemical contaminants, maritime traffic, and acoustic disturbances are the main pressures identified.

Circumpolar Arctic Populations: Cook Inlet, Bering Sea, Hudson Bay

Arctic populations are generally more numerous, but some are in critical condition. The Cook Inlet population (Alaska) is classified as "critically endangered" by NOAA, with fewer than 280 individuals counted in the latest aerial surveys (NOAA Fisheries). The Bering Sea and Hudson Bay populations are larger numerically but face growing pressure from sea ice reduction.

Svalbard and White Sea Belugas

Svalbard belugas (Norway) form a distinct population frequenting the archipelago's fjords in summer. Their numbers are poorly known. The White Sea population (Russia) is better documented, with summer gatherings in the Dvina and Onega estuaries. It is subject to regulated subsistence hunting by Russian authorities.

Global Figures and IUCN Assessment by Sub-Population

St. Lawrence Estuary and Saguenay Fjord (Canada)

This is the most accessible site for European observers. The resident population is present year-round in the estuary, with maximum concentration from May to October in the Tadoussac and Saguenay Fjord area. Local operators offer zodiac and large boat trips from Tadoussac and Baie-Sainte-Catherine. The Saguenay–St. Lawrence Marine Park strictly regulates approaches.

Somerset Bay and Cunningham Inlet (Nunavut, Canada)

Cunningham Inlet is one of the most spectacular summer gathering sites: several thousands of belugas concentrate there each summer to molt and calve in warm shallow waters. The observation season is short, generally July and August. Access is difficult and expensive; local operators note that most visitors arrive by charter flight from Resolute Bay.

Cook Inlet (Alaska, USA)

Beluga presence in Cook Inlet, near Anchorage, has been documented for decades. However, the population is critically endangered, and sightings have become rare. NOAA researchers conduct annual census overflights. Tourist observation is very limited, and authorities discourage unguided approaches.

Svalbard (Norway)

Belugas frequent Svalbard fjords during the Arctic summer, mainly from June to September. Field observers report groups of varying sizes in the northern and eastern fjords of the archipelago. Access is mainly from Longyearbyen by cruise ship or expedition boat. Weather conditions and ice presence strongly influence sightings.

White Sea (Russia)

Summer gatherings in the White Sea estuaries have been documented since the 19th century. The optimal season runs from June to September. International access is complex depending on periods. Recent scientific data on this population mainly come from Russian teams at the Moscow Institute of Oceanology.

Canadian Regulations in the Saguenay–St. Lawrence Marine Park

The most detailed regulatory framework for belugas is Canadian. In the Saguenay–St. Lawrence Marine Park, the law prohibits approaching belugas closer than 400 meters by motorboat. Entering the water within 400 meters is also prohibited. These distances exceed those for other cetaceans in the same area, reflecting this population's particular vulnerability.

Minimum Distances Recommended by Conservation Organizations

Outside the Canadian framework, conservation organizations recommend a minimum distance of 200 to 300 meters depending on context. The Whale and Dolphin Conservation (WDC) and GREMM emphasize increasing these distances in the presence of females with calves, feeding groups, or resting behaviors.

Behaviors to Avoid: Engine Noise, Head-On Approaches, Group Separation

The most frequent errors documented by operators and park managers are: direct head-on approaches (cutting across the group's path), keeping engines running in close proximity, and encircling attempts that separate individuals. These behaviors generate documented stress through changes in respiratory rate and trajectory (Lesage et al., 2017).

High Quality Whale Watching Charter and Criteria for a Responsible Operator

The High Quality Whale Watching (HQWW) charter defines concrete criteria: guide training, distance compliance, engines off or idling during observations, no feeding. Before booking a trip, I always check if the operator adheres to this charter or a recognized local equivalent. In Quebec, the Baleines en vue label applies similar criteria.

Contributing to Citizen Science via Happywhale and Photo-ID

Photo-ID for belugas relies mainly on skin marks, scars, dorsal ridge shape, and residual pigmentation in young adults. Sufficiently high-quality photos can be submitted to Happywhale, which integrates them into individual tracking databases. In Quebec, the GREMM also collects sightings and images via its citizen science network. These citizen contributions directly feed population estimates and movement studies.

Chemical Pollution and Bioaccumulation of Contaminants

Bioaccumulation of organochlorines (PCBs, DDT and derivatives) and heavy metals is the best-documented threat for the St. Lawrence population. Belugas there accumulate some of the highest contaminant concentrations ever measured in a wild cetacean, due to their high trophic position and high fat content (De Guise et al., 1994; GREMM). Tumors and immune pathologies have been linked to these contamination levels.

Climate Warming and Sea Ice Reduction

The reduction of the Arctic sea ice directly alters habitats and food resources for circumpolar populations. The opening of new shipping routes in the Arctic exposes previously little-disturbed areas to growing traffic. For Hudson Bay and Bering Sea populations, climate models project significant ice cover reduction by 2050 (IPCC, 2021).

Maritime Traffic and Noise Pollution

Commercial traffic in the St. Lawrence estuary has increased steadily since the 1990s. Noise levels measured in some marine park sectors exceed thresholds beyond which beluga acoustic communication is disrupted (Lesage et al., 2017). Vessel speed reduction measures have been tested under the Baleines en direct program with encouraging results on noise reduction.

Subsistence Hunting: Regulation and Issues for Indigenous Communities

Subsistence beluga hunting is practiced by several circumpolar Indigenous communities (Canadian Inuit, Siberian and Alaskan communities). It is regulated by quotas negotiated with national authorities. For large populations, the impact of this hunting is considered limited. For already fragile populations like Cook Inlet, any additional harvest is problematic.

Recovery Programs and Measurable Results

In Canada, the St. Lawrence Beluga Recovery Plan (Fisheries and Oceans Canada) has produced partial results: reduction of some contaminants following PCB bans, creation of the marine park, approach regulations. However, the population shows no clear signs of recovery since the 2000s. The GREMM tracks births and mortalities annually: calf mortality rates remain concerning, with unusual mortality events documented since 2008.