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Beluga whale[1]
Temporal range: Quaternary–Recent
A beluga whale
At City of Arts and Sciences, Spain
Size comparison to an average human
Size compared to an average human
CITES Appendix II (CITES)[3]
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Artiodactyla
Infraorder: Cetacea
Family: Monodontidae
Genus: Delphinapterus
Lacépède, 1804
Species:
D. leucas
Binomial name
Delphinapterus leucas
(Pallas, 1776)
Beluga range

The beluga whale (/bɪˈlɡə/;[4] Delphinapterus leucas) is an Arctic and sub-Arctic cetacean. It is one of two members of the family Monodontidae, along with the narwhal, and the only member of the genus Delphinapterus. It is also known as the white whale, as it is the only cetacean to regularly occur with this colour; the sea canary, due to its high-pitched calls; and the melonhead, though that more commonly refers to the melon-headed whale, which is an oceanic dolphin.

The beluga is adapted to life in the Arctic, with anatomical and physiological characteristics that differentiate it from other cetaceans. Amongst these are its all-white colour and the absence of a dorsal fin, which allows it to swim under ice with ease.[5] It possesses a distinctive protuberance at the front of its head which houses an echolocation organ called the melon, which in this species is large and deformable. The beluga's body size is between that of a dolphin and a true whale, with males growing up to 5.5 m (18 ft) long and weighing up to 1,600 kg (3,530 lb). This whale has a stocky body. Like many cetaceans, a large percentage of its weight is blubber (subcutaneous fat). Its sense of hearing is highly developed and its echolocation allows it to move about and find breathing holes under sheet ice.

Belugas are gregarious and form groups of 10 animals on average, although during the summer, they can gather in the hundreds or even thousands in estuaries and shallow coastal areas. They are slow swimmers, but can dive to 700 m (2,300 ft) below the surface. They are opportunistic feeders and their diets vary according to their locations and the season. The majority of belugas live in the Arctic Ocean and the seas and coasts around North America, Russia, and Greenland; their worldwide population is thought to number around 200,000.[6][7] They are migratory and the majority of groups spend the winter around the Arctic ice cap; when the sea ice melts in summer, they move to warmer river estuaries and coastal areas. Some populations are sedentary and do not migrate over great distances during the year.

The native peoples of North America and Russia have hunted belugas for many centuries. They were also hunted by non-natives during the 19th century and part of the 20th century. Hunting of belugas is not controlled by the International Whaling Commission, and each country has developed its own regulations in different years. Currently, some Inuit in Canada and Greenland, Alaska Native groups and Russians are allowed to hunt belugas for consumption as well as for sale, as aboriginal whaling is excluded from the International Whaling Commission 1986 moratorium on hunting. The numbers have dropped substantially in Russia and Greenland, but not in Alaska and Canada. Other threats include natural predators (polar bears and killer whales), contamination of rivers (as with polychlorinated biphenyl (PCBs) which bioaccumulate up the food chain), climate change and infectious diseases. The beluga was placed on the International Union for Conservation of Nature's Red List in 2008 as being "near threatened"; the subpopulation from the Cook Inlet in Alaska is considered critically endangered and is under the protection of the United States' Endangered Species Act. Of all seven extant Canadian beluga populations, those inhabiting eastern Hudson Bay, Ungava Bay, and the St. Lawrence River are listed as endangered.

Belugas are one of the most commonly kept cetaceans in captivity and are housed in aquariums, dolphinariums and wildlife parks in North America, Europe and Asia. They are considered charismatic because of their docile demeanour and characteristic smile, communicative nature,[8] and supple, graceful movement.[9]

Taxonomy

Skull of a cross between a narwhal and a beluga whale, at the Zoological Museum, Copenhagen

The beluga was first described in 1776 by Peter Simon Pallas.[1] It is a member of the family Monodontidae, which is in turn part of the parvorder Odontoceti (toothed whales).[1] The Irrawaddy dolphin was once placed in the same family, though recent genetic evidence suggests these dolphins belong to the family Delphinidae.[10][11] The narwhal is the only other species within the Monodontidae.[12] A skull has been discovered with intermediate characteristics supporting the hypothesis that hybridisation is possible between these two species.[13]

The name of the genus, Delphinapterus, means "dolphin without fin" (from the Greek δελφίν (delphin), dolphin and απτερος (apteros), without fin) and the species name leucas means "white" (from the Greek λευκας (leukas), white).[14] The Red List of Threatened Species gives both beluga and white whale as common names, though the former is now more popular. The English name comes from the Russian белу́га, which derives from the word белый (bélyj), meaning "white".[14] Nowadays the word белу́га in Russian refers to the beluga sturgeon, while the whale is called almost similarly - белу́ха ("belúha").[citation needed]

The whale is also colloquially known as the "sea canary" on account of its high-pitched squeaks, squeals, clucks, and whistles. A Japanese researcher claimed that he taught a beluga to "talk" by using these sounds to identify three different objects, offering hope that humans may one day be able to communicate effectively with sea mammals.[15] A similar observation has been made by Canadian researchers, where a beluga which died in 2007 "talked" when he was still a subadult. Another example is NOC, a beluga whale that could mimic the rhythm and tone of human language. Beluga whales in the wild have been reported to imitate human voices.[16]

Evolution

Skeleton of D. leucas
3d model of the skeleton
Skeleton of D. leucas

Mitochondrial DNA studies have shown modern cetaceans last shared a common ancestor between 25 and 34 million years ago[17][18] The superfamily Delphinoidea (which contains monodontids, dolphins and porpoises) split from other toothed whales, odontoceti, between 11 and 15 million years ago. Monodontids then split from dolphins (Delphinidae) and later from porpoises (Phocoenidae), their closest relatives in evolutionary terms.[17] In 2017 the genome of a beluga whale was sequenced, comprising 2.327 Gbp of assembled genomic sequence that encoded 29,581 predicted genes.[19] The authors estimated that the genome-wide sequence similarity between beluga whales and killer whales is 97.87%.[citation needed]

The beluga's earliest known distinctive ancestors include the prehistoric Denebola brachycephala from the late Miocene epoch (9–10 million years ago),[20][21] and Bohaskaia monodontoides, from the early Pliocene (3–5 million years ago).[22] Fossil evidence from Baja California[23] and Virginia indicate the family once inhabited warmer waters.[22] A fossil of the monodontid Casatia thermophila, from five million years ago, provides the strongest evidence that monodontids once inhabited warmer waters, as the fossil was found alongside fossils of tropical species such as bull and tiger sharks.[24]

The fossil record also indicates that, in comparatively recent times, the beluga's range varied with that of the polar ice packs expanding during ice ages and contracting when the ice retreated.[25] Counter-evidence to this theory comes from the finding in 1849 of fossilised beluga bones in Vermont in the United States, 240 km (150 mi) from the Atlantic Ocean. The bones were discovered during construction of the first railroad between Rutland and Burlington in Vermont, when workers unearthed the bones of a mysterious animal in Charlotte. Buried nearly 10 ft (3.0 m) below the surface in a thick blue clay, these bones were unlike those of any animal previously discovered in Vermont. Experts identified the bones as those of a beluga. Because Charlotte is over 150 mi (240 km) from the nearest ocean, early naturalists were at a loss to explain the presence of the bones of a marine mammal buried beneath the fields of rural Vermont.[citation needed]

The remains were found to be preserved in the sediments of the Champlain Sea, an extension of the Atlantic Ocean within the continent resulting from the rise in sea level at the end of the ice ages some 12,000 years ago.[26] Today, the Charlotte whale is the official Vermont State Fossil (making Vermont the only state whose official fossil is that of a still extant animal).[27]

The cranium and mandible of the Charlotte whale (white) restored with the skull of a modern beluga whale (black)

Description

Front view of a beluga whale in captivity

Its body is round, particularly when well fed, and tapers less smoothly to the head than the tail. The sudden tapering to the base of its neck gives it the appearance of shoulders, unique among cetaceans. The tail-fin grows and becomes increasingly and ornately curved as the animal ages. The flippers are broad and short—making them almost square-shaped.

Longevity

Preliminary investigations suggested a beluga's life expectancy was rarely more than 30 years.[28] The method used to calculate the age of a beluga is based on counting the layers of dentine and dental cement in a specimen's teeth, which were originally thought to be deposited once or twice a year. The layers can be readily identified as one layer consists of opaque dense material and the other is transparent and less dense. It is therefore possible to estimate the age of the individual by extrapolating the number of layers identified and the estimated frequency with which the deposits are laid down.[29] A 2006 study using radiocarbon dating of the dentin layers showed the deposit of this material occurs with a lesser frequency (once per year) than was previously thought. The study therefore estimated belugas can live for 70 or 80 years.[30] However, recent studies suggest that it is unclear as to whether belugas receive a different number of layers per year depending on the age of the animal (for example young belugas may only receive an additional one layer per year), or simply just one layer per year or every other year.[31][citation needed]

Size

The species presents a moderate degree of sexual dimorphism, as the males are 25% longer than the females and are sturdier.[32] Adult male belugas can range from 3.5 to 5.5 m (11 to 18 ft), while the females measure 3 to 4.1 m (9.8 to 13.5 ft).[33] Males weigh between 1,100 and 1,600 kg (2,430 and 3,530 lb), and occasionally up to 1,900 kg (4,190 lb) while females weigh between 700 and 1,200 kg (1,540 and 2,650 lb).[34][35] They rank as mid-sized species among toothed whales.[36]

Individuals of both sexes reach their maximum size by the time they are 10 years old.[37] The beluga's body shape is stocky and fusiform (cone-shaped with the point facing backwards), and they frequently have folds of fat, particularly along the ventral surface.[38] Between 40% and 50% of their body weight is fat, which is a higher proportion than for cetaceans that do not inhabit the Arctic, where fat only represents 30% of body weight.[39][40] The fat forms a layer that covers all of the body except the head, and it can be up to 15 cm (5.9 in) thick. It acts as insulation in waters with temperatures between 0 and 18 °C, as well as being an important reserve during periods without food.[41]

Colour

Head of a beluga showing its distinctive white colouring and the large frontal prominence that houses the melon

The adult beluga is rarely mistaken for any other species, because it is completely white or whitish-grey in colour.[42] Calves are usually born grey,[33] and by the time they are a month old, have turned dark grey or blue grey. They then start to progressively lose their pigmentation until they attain their distinctive white colouration, at the age of seven years in females and nine in males.[42] The white colouration of the skin is an adaptation to life in the Arctic that allows belugas to camouflage themselves in the polar ice caps as protection against their main predators, polar bears and killer whales.[43] Unlike other cetaceans, the belugas seasonally shed their skin.[44] During the winter, the epidermis thickens and the skin can become yellowish, mainly on the back and fins. When they migrate to the estuaries during the summer, they rub themselves on the gravel of the riverbeds to remove the cutaneous covering.[44]

Head and neck

Spiracle in the back of a beluga's head
The skull

Like most toothed whales, the beluga has a compartment found at the centre of the forehead that contains an organ used for echolocation called a melon, which contains fatty tissue.[45] The shape of the beluga's head is unlike that of any other cetacean, as the melon is extremely bulbous, lobed and visible as a large frontal prominence.[45] Another distinctive characteristic it possesses is the melon is malleable; its shape is changed during the emission of sounds.[12] The beluga is able to change the shape of its head by blowing air around its sinuses to focus the emitted sounds.[46][47] This organ contains fatty acids, mainly isovaleric acid (60.1%) and long-chain branched acids (16.9%), a very different composition from its body fat, and which could play a role in its echolocation system.[48]

Unlike many dolphins and whales, the seven vertebrae in the neck are not fused together, allowing the animal to turn its head laterally without needing to rotate its body.[49] This gives the head a lateral manoeuvrability that allows an improved field of view and movement and helps in catching prey and evading predators in deep water.[43] The rostrum has about eight to ten small, blunt and slightly curved teeth on each side of the jaw and a total of 36 to 40 teeth.[50] Belugas do not use their teeth to chew, but for catching hold of their prey; they then tear them up and swallow them nearly whole.[51]

Belugas only have a single spiracle, which is located on the top of the head behind the melon, and has a muscular covering, allowing it to be completely sealed. Under normal conditions, the spiracle is closed and an animal must contract the muscular covering to open the spiracle.[52] A beluga's thyroid gland is larger than that of terrestrial mammals—weighing three times more than that of a horse—which helps it to maintain a greater metabolism during the summer when it lives in river estuaries.[53] It is the marine cetacean that most frequently develops hyperplastic and neoplastic lesions of the thyroid.[54]

Fins

A beluga showing its tail fin in shallow water in Vancouver Aquarium, Canada

The fins retain the bony vestiges of the beluga's mammalian ancestors, and are firmly bound together by connective tissue.[38] The fins are small in relation to the size of the body, rounded and oar-shaped and slightly curled at the tips.[14] These versatile extremities are mainly used as a rudder to control direction, to work in synchrony with the tailfin and for agile movement in shallow waters up to 3 m (9.8 ft) deep.[37] The fins also contain a mechanism for regulating body temperature, as the arteries feeding the fin's muscles are surrounded by veins that dilate or contract to gain or lose heat.[38][55] The tailfin is flat with two oar-like lobes, it does not have any bones, and is made up of hard, dense, fibrous connective tissue. The tailfin has a distinctive curvature along the lower edge.[38] The longitudinal muscles of the back provide the ascending and descending movement of the tailfin, which has a similar thermoregulation mechanism to the pectoral fins.[38]

Belugas have a dorsal ridge, rather than a dorsal fin.[33] The absence of the dorsal fin is reflected in the genus name of the species—apterus the Greek word for "wingless". The evolutionary preference for a dorsal ridge rather than a fin is believed to be an adaptation to under-ice conditions, or possibly as a way of preserving heat.[12] The crest is hard and, along with the head, can be used to open holes in ice up to 8 cm (3.1 in) thick.[56]

Senses

Emission and reception of sounds in a toothed whale

The beluga has a very specialised sense of hearing and its auditory cortex is highly developed. It can hear sounds within the range of 1.2 to 120 kHz, with the greatest sensitivity between 10 and 75 kHz,[57] where the average hearing range for humans is 0.02 to 20 kHz.[58] The majority of sounds are most probably received by the lower jaw and transmitted towards the middle ear. In the toothed whales, the lower jawbone is broad with a cavity at its base, which projects towards the place where it joins the cranium. A fatty deposit inside this small cavity connects to the middle ear.[59] Toothed whales also possess a small external auditory hole a few centimetres behind their eyes; each hole communicates with an external auditory conduit and an eardrum. It is not known if these organs are functional or simply vestigial.[59]

Belugas are able to see within and outside of water, but their vision is relatively poor when compared to dolphins.[60] Their eyes are especially adapted to seeing under water, although when they come into contact with the air, the crystalline lens and the cornea adjust to overcome the associated myopia (the range of vision under water is short).[60] A beluga's retina has cones and rods, which also suggests they can see in low light. The presence of cone cells indicates they can see colours, although this suggestion has not been confirmed.[60] Glands located in the medial corner of their eyes secrete an oily, gelatinous substance that lubricates the eye and helps flush out foreign bodies. This substance forms a film that protects the cornea and the conjunctiva from pathogenic organisms.[60]

Studies on captive animals show they seek frequent physical contact with other belugas.[43] Areas in the mouth have been found that could act as chemoreceptors for different tastes, and they can detect the presence of blood in water, which causes them to react immediately by displaying typical alarm behaviour.[43] Like the other toothed whales, their brains lack olfactory bulbs and olfactory nerves, which suggests they do not have a sense of smell.[45]

Behaviour

Social structure and play

Aerial view of a pod of belugas swimming at the surface

These cetaceans are highly sociable and they regularly form small groups, or pods, that may contain between two and 25 individuals, with an average of 10 members.[61] Pods tend to be unstable, meaning individuals tend to move from pod to pod. Radio tracking has even shown belugas can start out in one pod and within a few days be hundreds of miles away from that pod.[62] Beluga whale pods can be grouped into three categories, nurseries (which consist of mother and calves), bachelors (which consist of all males) and mixed groups. Mixed groups contain animals of both sexes.[63][50] Many hundreds and even thousands of individuals can be present when the pods join in river estuaries during the summer. This can represent a significant proportion of the total population and is when they are most vulnerable to being hunted.[64]

They are cooperative animals and frequently hunt in coordinated groups.[65] The animals in a pod are very sociable and often chase each other as if they are playing or fighting, and they often rub against each other.[66] Often individuals will surface and dive together in a synchronized manner, in a behavior known as milling.

In captivity, they can be seen to be constantly playing, vocalising and swimming around each other.[67] In one case, one whale blew bubbles, while the other one popped them. There have also been reports of beluga whales copying and imitating one another, similar to a game of Simon-says. There have also been reports of them displaying physical affection, via mouth to mouth contact. They also show a great deal of curiosity towards humans and frequently approach the windows in the tanks to observe them.[68]

Belugas also show a great degree of curiosity towards humans in the wild, and frequently swim alongside boats.[69] They also play with objects they find in the water; in the wild, they do this with wood, plants, dead fish and bubbles they have created.[39] During the breeding season, adults have been observed carrying objects such as plants, nets, and even the skeleton of a dead reindeer on their heads and backs.[67] Captive females have also been observed displaying this behavior, carrying items such as floats and buoys, after they have lost a calf. Experts consider this interaction with the objects to be a substitute behavior.[70]

In captivity, mothering behavior among belugas depends on the individual. Some mothers are extremely attentive while other mothers are so blasé, that they have actually lost their calves. In aquaria, there have been cases where dominant females have stolen calves from mothers, particularly if they have lost a calf or if they are pregnant. After giving birth, dominant females will return the calf back to their mother. Additionally, male calves will temporarily leave their mothers to interact with an adult male who can serve as a role model for the calf, before they return to their mothers. Male calves are also frequently seen interacting with each other.

Swimming and diving

Belugas are slower swimmers than the other toothed whales, such as the killer whale and the common bottlenose dolphin, because they are less hydrodynamic and have limited movement of their tail-fins, which produce the greatest thrust.[71] They frequently swim at speeds between 3 and 9 km/h (1.9 and 5.6 mph), although they are able to maintain a speed of 22 km/h for up to 15 min.[50] Unlike most cetaceans, they are capable of swimming backwards.[37][72] Belugas swim on the surface between 5% and 10% of the time, while for the rest of the time they swim at a depth sufficient enough to cover their bodies.[37] They do not jump out of the water like dolphins or killer whales.[14]

These animals usually only dive to depths to 20 m (66 ft),[73] although they are capable of diving to greater depths. Individual captive animals have been recorded at depths between 400 and 647 m below sea level,[74] while animals in the wild have been recorded as diving to a depth of more than 700 m, with the greatest recorded depth being over 900 m.[75] A dive normally lasts 3 to 5 minutes, but can last up to over 20 minutes.[76][50][75][77] In the shallower water of the estuaries, a diving session may last around two minutes; the sequence consists of five or six rapid, shallow dives followed by a deeper dive lasting up to one minute.[37] The average number of dives per day varies between 31 and 51.[75]

All cetaceans, including belugas, have physiological adaptations designed to conserve oxygen while they are under water.[78] During a dive, these animals will reduce their heart rate from 100 beats a minute to between 12 and 20.[78] Blood flow is diverted away from certain tissues and organs and towards the brain, heart and lungs, which require a constant oxygen supply.[78] The amount of oxygen dissolved in the blood is 5.5%, which is greater than that found in land-based mammals and is similar to that of Weddell seals (a diving marine mammal). One study found a female beluga had 16.5 L of oxygen dissolved in her blood.[79] Lastly, the beluga's muscles contain high levels of the protein myoglobin, which stores oxygen in muscle. Myoglobin concentrations in belugas are several times greater than for terrestrial mammals, which help prevent oxygen deficiency during dives.[80]

Beluga whales often accompany bowhead whales, for curiosity and to secure polynya feasibility to breathe as bowheads are capable of breaking through ice from underwater by headbutting.[81]

Diet

Pacific salmon, the staple diet of belugas from Alaska

Belugas play an important role in the structure and function of marine resources in the Arctic Ocean, as they are the most abundant toothed whales in the region.[82] They are opportunistic feeders; their feeding habits depend on their locations and the season.[32] For example, when they are in the Beaufort Sea, they mainly eat Arctic cod (Boreogadus saida) and the stomachs of belugas caught near Greenland were found to contain rose fish (Sebastes marinus), Greenland halibut (Reinhardtius hippoglossoides) and northern shrimp (Pandalus borealis),[83] while in Alaska their staple diet is Coho salmon (Oncorhynchus kisutch).[84] In general, the diets of these cetaceans consist mainly of fish; apart from those previously mentioned, other fish they feed on include capelin (Mallotus villosus), smelt, sole, flounder, herring, sculpin and other types of salmon.[85] They also consume a great quantity of invertebrates, such as shrimp, squid, crabs, clams, octopus, sea snails, bristle worms and other deep-sea species.[85][86] Belugas feed mainly in winter as their blubber is thickest in later winter and early spring, and thinnest in the fall. Inuit observation has led scientists to believe that belugas do not hunt during migration, at least in Hudson Bay.[87]

The diet of Alaskan belugas is quite diverse and varies depending on season and migratory behavior. Belugas in the Beaufort Sea mainly feed on staghorn and shorthorn sculpin, walleye pollock, Arctic cod, saffron cod and Pacific sand lance. Shrimp are the most common invertebrate eaten, with octopus, amphipods and echiurids being other sources of invertebrate prey. The most common prey species for belugas in the Eastern Chukchi Sea appears to be shrimp, echiurid worms, cephalopods and polychaetes. The largest prey item consumed by beluga whales in the Eastern Chukchi Sea seems to be saffron cod. Beluga whales in the Eastern Bering Sea feed on a variety of fish species including saffron cod, rainbow smelt, walleye pollock, Pacific salmon, Pacific herring and several species of flounder and sculpin. The primary invertebrate consumed is shrimp. The primary prey item in regard to fish species for belugas in Bristol Bay appears to be the five species of salmon, with sockeye being the most prevalent. Smelt is also another common fish family eaten by belugas in this region. Shrimp is the most prevalent invertebrate prey item. The most common prey items for belugas in Cook Inlet appear to be salmon, cod and smelt.[88]

Animals in captivity eat 2.5% to 3.0% of their body weight per day, which equates to 18.2 to 27.2 kg (40 to 60 lb).[89] Like their wild counterparts, captive belugas were found to eat less in the fall.[90]

Foraging on the seabed typically takes place at depths between 20 and 40 m (66 and 131 ft),[91] although they can dive to depths of 700 m (2,300 ft) in search of food.[75] Their flexible necks provide a wide range of movement while they are searching for food on the ocean floor. Some animals have been observed to suck up water and then forcefully expel it to uncover their prey hidden in the silt on the seabed.[65] As their teeth are neither large nor sharp, belugas must use suction to bring their prey into their mouths; it also means their prey has to be consumed whole, which in turn means it cannot be too large or the belugas run the risk of it getting stuck in their throats.[92] They also join into coordinated groups of five or more to feed on shoals of fish by steering the fish into shallow water, where the belugas then attack them.[65] For example, in the estuary of the Amur River, where they mainly feed on salmon, groups of six or eight individuals join to surround a shoal of fish and prevent their escape. Individuals then take turns feeding on the fish.[56]

Reproduction

Underwater photo of calf swimming slightly below and behind its mother
Female and calf

Estimations of the age of sexual maturity for beluga whales vary considerably; the majority of authors estimate males reach sexual maturity when they are between nine and fifteen years old, and females reach maturity between eight and fourteen years old.[93] The average age at which females first give birth is 8.5 years and fertility begins to decrease when they are 25, eventually undergoing menopause,[94][95] and ceasing reproductive potential with no births recorded for females older than 41.[93] There is a slight difference on the sexual maturation period between males and females. The male beluga whales take seven to nine years to become sexually mature, while the females take four to seven years.[96]

Female belugas typically give birth to one calf every three years.[33] Most mating occurs from February to May, but some occurs at other times of year.[12] The beluga may have delayed implantation.[12] Gestation has been estimated to last 12.0 to 14.5 months,[33] but information derived from captive females suggests a period up to 475 days (15.8 months).[97] During the mating season, the testes of belugas double in weight. Testosterone levels increase, but seems to be independent of copulation. Copulation typically takes place between 3 and 4 AM.

Calves are born over a protracted period that varies by location. In the Canadian Arctic, calves are born between March and September, while in Hudson Bay, the peak calving period is in late June, and in Cumberland Sound, most calves are born from late July to early August.[98] Births usually take place in bays or estuaries where the water is between 10 and 15 °C.[61] Newborns are about 1.5 m (4 ft 11 in) long, weigh about 80 kg (180 lb), and are grey in colour.[50] They are able to swim alongside their mothers immediately after birth.[99] The newborn calves nurse under water and initiate lactation a few hours after birth; thereafter, they feed at intervals around an hour.[65] Studies of captive females have indicated their milk composition varies between individuals and with the stage of lactation; it has an average content of 28% fat, 11% protein, 60.3% water, and less than 1% residual solids.[100] The milk contains about 92 cal per ounce.[101]

The calves remain dependent on their mothers for nursing for the first year, when their teeth appear.[61] After this, they start to supplement their diets with shrimp and small fish.[45] The majority of the calves continue nursing until they are 20 months old, although occasionally lactation can continue for more than two years,[50] and lactational anoestrus may not occur. Alloparenting (care by females different from the mother) has been observed in captive belugas, including spontaneous and long-term milk production. This suggests this behaviour, which is also seen in other mammals, may be present in belugas in the wild.[102]

Hybrids have been documented between the beluga and the narwhal (specifically offspring conceived by a beluga father and a narwhal mother), as one, perhaps even as many as three, such hybrids were killed and harvested during a sustenance hunt. Whether or not these hybrids could breed remains unknown. The unusual dentition seen in the single remaining skull indicates the hybrid hunted on the seabed, much as walruses do, indicating feeding habits different from those of either parent species.[103][104]

Communication and echolocation

Vocalisations of Delphinapterus leucas published by NOAA

Belugas use sounds and echolocation for movement, communication, to find breathing holes in the ice, and to hunt in dark or turbid waters.[46] They produce a rapid sequence of clicks that pass through the melon, which acts as an acoustic lens to focus the sounds into a beam that is projected forward through the surrounding water.[101] These sounds spread through the water at a speed of nearly 1.6 km per second, some four times faster than the speed of sound in air. The sound waves reflect from objects and return as echoes that are heard and interpreted by the animal.[46] This enables them to determine the distance, speed, size, shape and the object's internal structure within the beam of sound. They use this ability when moving around thick Arctic ice sheets, to find areas of unfrozen water for breathing, or air pockets trapped under the ice.[61]

Some evidence indicates that belugas are highly sensitive to noise produced by humans. In one study, the maximum frequencies produced by an individual located in San Diego Bay, California, were between 40 and 60 kHz. The same individual produced sounds with a maximum frequency of 100 to 120 kHz when transferred to Kaneohe Bay in Hawaii. The difference in frequencies is thought to be a response to the difference in environmental noise in the two areas.[105] In special circumstances, beluga whale sounds have been reported to resemble human speech.[106][107]

These animals communicate using sounds of high frequency; their calls can sound like bird songs, so belugas were nicknamed "canaries of the sea".[108] Like the other toothed whales, belugas do not possess vocal cords and the sounds are probably produced by the movement of air between the nasal sacks, which are located near to the blowhole.[46]

Belugas are among the most vocal cetaceans.[109] They use their vocalisations for echolocation, during mating and for communication. They possess a large repertoire, emitting up to 11 different sounds, such as cackles, whistles, trills and squawks.[46] They make sounds by grinding their teeth or splashing, but they rarely use body language.[46]

There is debate as to whether cetacean vocalizations can constitute a language. A study conducted in 2015 determined that European beluga signals share physical features comparable to vowels. These sounds were found to be stable throughout time, but varied among different geographical locations. The further away the populations were from each other, the more varied the sounds were in relation to one another.[110]

Distribution

Circumpolar distribution of beluga populations showing the main subpopulations

The beluga inhabits a discontinuous circumpolar distribution in Arctic and sub-Arctic waters.[111] During the summer, they can mainly be found in deep waters ranging from 76°N to 80°N, particularly along the coasts of Alaska, northern Canada, western Greenland and northern Russia.[111] The southernmost extent of their range includes isolated populations in the St. Lawrence River in the Atlantic,[112] and the Amur River delta, the Shantar Islands and the waters surrounding Sakhalin Island in the Sea of Okhotsk.[113]

Migration

Belugas have a seasonal migratory pattern.[114] Migration patterns are passed from parents to offspring. Some travel as far as 6,000 kilometres (3,700 mi) per year.[115] When the summer sites become blocked with ice during the autumn, they move to spend the winter in the open sea alongside the pack ice or in areas covered with ice, surviving by using polynyas to surface and breathe.[116] In summer after the sheet ice has melted, they move to coastal areas with shallower water (1–3 m [3 ft 3 in – 9 ft 10 in] deep), although sometimes they migrate towards deeper waters (deeper than 800 m [2,600 ft]).[114] In the summer, they occupy estuaries and the waters of the continental shelf, and, on occasion, they even swim up the rivers.[114] A number of incidents have been reported where groups or individuals have been found hundreds or even thousands of kilometres from the ocean.[117][118] One such example comes from June 9, 2006, when a young beluga carcass was found in the Tanana River near Fairbanks in central Alaska, nearly 1,700 km (1,100 mi) from the nearest ocean habitat. Belugas sometimes follow migrating fish, leading Alaska state biologist Tom Seaton to speculate it had followed migrating salmon up the river at some point in the previous autumn.[119] The rivers they most often travel up include: the Northern Dvina, the Mezen, the Pechora, the Ob and the Yenisei in Asia; the Yukon and the Kuskokwim in Alaska, and the Saint Lawrence in Canada.[111] Spending time in a river has been shown to stimulate an animal's metabolism and facilitates the seasonal renewal of the epidermal layer.[53] In addition, the rivers represent a safe haven for newborn calves where they will not be preyed upon by killer whales.[12] Calves often return to the same estuary as their mother in the summer, meeting her sometimes even after becoming fully mature.[120] However, not all beluga whale populations summer in estuaries. Belugas from the Beaufort Sea stock were found to summer along the Eastern Beaufort Sea shelf, Amundsen Gulf and slope regions north and west of Banks Island, in addition to core areas in the Mackenzie River Estuary. Male belugas have been observed summering in deeper waters along Viscount Melville Sound, in depths of up to 600 metres (2,000 ft). The bulk of Eastern Chukchi Sea belugas summer over Barrow canyon.[121]

The migration season is relatively predictable, as it is basically determined by the amount of daylight and not by other variable physical or biological factors, such as the condition of the sea ice.[122] Vagrants may travel further south to areas such as Irish[123] and Scottish waters,[124] the islands of Orkney[125] and Hebrides,[126] and to Japanese waters.[127] There had been several vagrant individuals[128] that have demonstrated seasonal residencies at Volcano Bay,[129][130][131] and a unique whale were used to return annually to areas adjacent to Shibetsu in Nemuro Strait in the 2000s.[132] On rarer occasions, individuals of vagrancy can reach the Korean Peninsula.[133] A few other individuals have been confirmed to return to the coasts of Hokkaido, and one particular individual became a resident in brackish waters of Lake Notoro since in 2014.[134][135]

Some populations are not migratory and certain resident groups will stay in well-defined areas, such as in Cook Inlet, the estuary of the Saint Lawrence River and Cumberland Sound.[136] The population in Cook Inlet stays in the waters furthest inside the inlet during the summer until the end of autumn. Then during the winter, they disperse to the deeper water in the center of the inlet, but without completely leaving it.[137][138]

In April, the animals that spend the winter in the center and southwest of the Bering Sea move to the north coast of Alaska and the east coast of Russia.[136] The populations living in the Ungava Bay and the eastern and western sides of Hudson Bay overwinter together beneath the sea ice in Hudson Strait. Whales in James Bay that spend winter months within the basin, could be a distinct group from those in Hudson Bay.[139] The populations of the White Sea, the Kara Sea and the Laptev Sea overwinter in the Barents Sea.[136] In the spring, the groups separate and migrate to their respective summer sites.[136]

Habitat

Beluga in the mouth of the Churchill River in the Hudson Bay, Canada

Belugas exploit a varied range of habitats; they are most commonly seen in shallow waters close to the coast, but they have also been reported to live for extended periods in deeper water, where they feed and give birth to their young.[136]

In coastal areas, they can be found in coves, fjords, canals, bays and shallow waters in the Arctic Ocean that are continuously lit by sunlight.[39] They are also often seen during the summer in river estuaries, where they feed, socialize and give birth to young. These waters usually have a temperature between 8 and 10 °C.[39] The mudflats of Cook Inlet in Alaska are a popular location for these animals to spend the first few months of summer.[140] In the eastern Beaufort Sea, female belugas with their young and immature males prefer the open waters close to land, while the adult males live in waters covered by ice near the Canadian Arctic Archipelago. The younger males and females with slightly older young can be found nearer to the ice shelf.[141] Generally, the use of different habitats in summer reflects differences in feeding habits, risk from predators and reproductive factors for each of the subpopulations.[32]

Population

There are currently 22 stocks of beluga whales recognized:[142]

  1. James Bay – 14,500 individuals (belugas remain here all year round)
  2. Western Hudson Bay – 55,000 individuals
  3. Eastern Hudson Bay – 3,400–3,800 individuals
  4. Cumberland Sound – 1,151 individuals
  5. Ungava Bay – 32 individuals (maybe functionally extinct)
  6. St. Lawrence River Estuary – 889 individuals
  7. Eastern Canadian Arctic – 21,400 individuals
  8. Southwest Greenland – Extinct
  9. Eastern Chukchi Sea – 20,700 individuals
  10. Eastern Bering Sea – 7,000–9,200 individuals
  11. Eastern Beaufort Sea – 39,300 individuals
  12. Bristol Bay – 2,000–3,000 individuals
  13. Cook Inlet – 300 individuals
  14. White Sea – 5,600 individuals
  15. Kara Sea/Laptev Sea/Barents Sea – Data Deficient
  16. Ulbansky – 2,300
  17. Anadyr – 3,000
  18. Shelikhov – 2,666
  19. Sakhalin/Amur – 4,000 individuals
  20. Tugurskiy – 1,500 individuals
  21. Udskaya – 2,500 individuals
  22. Svalbard – 549 individuals[7]

The Yakutat Bay belugas are not considered to be a true stock because they have only been present in these waters since the 1980s, and are believed to be of Cook Inlet origin. It is estimated that less than 20 whales inhabit the bay year-round.[142] Overall the beluga population is estimated to be 150,000–200,000 animals.

Threats

Hunting

Beluga and narwhal catches
Illustration from 1883 showing Dena'ina hunting party harpooning a beluga in Cook Inlet, Alaska

The native populations of the Arctic in Alaska, Canada, Greenland and Russia hunt belugas, for both consumption and profit. Belugas have been easy prey for hunters due to their predictable migration patterns and the high population density in estuaries and surrounding coastal areas during the summer.[143]

Present

The number of animals killed is about 1,000 per year, (see table below. and its sources). Beluga whale hunting quotas in Canada and the United States are established using the Potential Biological Removal equation PBR = Nmin * 0.5 * Rmax * FR, to determine what constitutes a sustainable hunt. Nmin represents a conservative estimation of the population size, Rmax, represents the maximum rate of population increase and FR represents the recovery factor.[142]

Hunters in Hudson's Bay rarely eat the meat. They give a little to dogs, and leave the rest for wild animals.[144] Other areas may dry the meat for later consumption by humans. In Greenland the skin (muktuk) is sold commercially to fish factories,[145] and in Canada to other communities.[144] An average of one or two vertebrae and one or two teeth per beluga are carved and sold.[144] One estimate of the annual gross value received from Beluga hunts in Hudson Bay in 2013 was CA$600,000 for 190 belugas, or CA$3,000 per beluga. However, the net income, after subtracting costs in time and equipment, was a loss of CA$60 per person. Hunts receive subsidies, but they continue as a tradition, rather than for the money, and the economic analysis noted that whale watching may be an alternate revenue source. Of the gross income, CA$550,000 was for skin and meat, to replace beef, pork and chickens which would otherwise be bought. CA$50,000 was received for carved vertebrae and teeth.[144]

Russia now harvests 5 to 30 belugas per year for meat and captures an additional 20 to 30 per year for live export to Chinese aquaria.[146][147] However, in 2018, 100 were illegally captured for live export.[148][149]

Previous levels of commercial whaling have put the species in danger of extinction in areas such as Cook Inlet, Ungava Bay, the St. Lawrence River and western Greenland. Continued hunting by the native peoples may mean some populations will continue to decline. Northern Canadian sites are the focus of discussions between local communities and the Canadian government, with the objective of permitting sustainable hunting that does not put the species at risk of extinction.[150]

The total amount of landed (defined as belugas successfully hunted and retrieved) belugas averages 275 in regard to the Bering, Chukchi and Beaufort stocks from 1987 to 2006. The average annual landed harvest of belugas in the Beaufort Sea consisted of 39 individuals while the Chukchi harvest averaged 62 individuals. Bristol bay's annual average landed harvest was 17 while the Bering Sea's was 152. Statistical studies have demonstrated that subsistence hunting in Alaska did not significantly impact the population of the Alaskan beluga whale stocks. The number of belugas struck and lost did not seem to profoundly impact Chukchi and Bering Sea belugas.[151]

Past

Commercial whaling by European, American and Russian whalers during the 18th and 19th centuries decreased beluga populations in the Arctic.[143][152][153] The animals were hunted for their meat and blubber, while the Europeans used the oil from the melon as a lubricant for clocks, machinery and lighting in lighthouses.[143] Mineral oil replaced whale oil in the 1860s, but into the early 20th century the cured skin was still used to make horse harnesses and machine belts for saw mills and shoelaces. The cured skin is the only cetacean skin that is sufficiently thick to be used as leather, and was used to manufacture some of the first bulletproof vests.[143] [154][155]

Russia had large hunts, peaking in the 1930s at 4,000 per year and the 1960s at 7,000 per year, for a total of 86,000 from 1915 to 2014.[146][152] Canada hunted a total of 54,000 from 1731 to 1970.[156] Between 1868 and 1911, Scottish and American whalers killed more than 20,000 belugas in Lancaster Sound and Davis Strait.[143]

During the 1920s, fishermen in the Saint Lawrence River estuary considered belugas to be a threat to the fishing industry, as they eat large quantities of cod, salmon, tuna and other fish caught by the local fishermen.[155] The presence of belugas in the estuary was, therefore, considered to be undesirable; in 1928, the Government of Quebec offered a reward of 15 dollars for each dead beluga.[157] The Quebec Department of Fisheries launched a study into the influence of these cetaceans on local fish populations in 1938. The unrestricted killing of belugas continued into the 1950s, when the supposed voracity of the belugas was found to be overestimated and did not adversely affect fish populations.[155] L'Isle-aux-Coudres is the setting for the classic 1963 National Film Board of Canada documentary Pour la suite du monde, which depicts a one-off resurrection of the beluga hunt; one animal is caught live, and transported by truck to an aquarium in the big city. The method of capture is akin to dolphin drive hunting.

Beluga catches by location

Annual table showing the number of belugas caught in Canada, Russia, Greenland and Alaska each year, from 2016 back to 1954
Beaufort Sea, Mackenzie, Paulatuk, Ulukhaktok, Canada Nunavut, Canada Nunavik, Quebec, Canada Western Arctic, Russia, hunted for meat Eastern Arctic, Russia, hunted for meat Sea of Okhotsk, Russia, hunted for meat All areas of Russia, live export Year Canada total Greenland USSR+ Russia total US (Alaska) World total, incomplete Lost at sea as % of caught
157 2016 157 246
83 303 2015 386 156 326 868
136 302 30 23 2014 438 317 53 346 1154 2%
92 207 30 23 2013 299 353 53 367 1072 2%
102 207 30 44 2012 309 245 74 360 988 4%
72 207 30 33 2011 279 179 63 288 809 3%
94 207 30 30 2010 301 222 60 318 901 3%
102 207 30 24 2009 309 286 54 253 902 6%
79 207 30 25 2008 286 330 55 254 925 8%
85 207 30 0 2007 292 145 30 576 1043 2%
126 207 30 20 2006 333 169 50 226 778 3%
108 207 30 31 2005 315 231 61 282 889 2%
142 207 30 25 2004 349 246 55 234 884 8%
125 250 207 30 26 2003 582 510 56 251 1399 9%
89 170 210 30 10 2002 469 510 40 362 1381 3%
96 370 30 22 2001 466 560 52 416 1494 1%
91 116 243 30 10 2000 450 733 40 280 1503 8%
102 207 243 30 23 1999 552 590 53 217 1412 19%
93 137 243 30 23 1998 473 873 53 342 1741 8%
123 376 243 30 23 1997 742 682 53 276 1753 8%
139 203 243 30 23 1996 585 681 53 389 1708 16%
143 30 23 1995 143 960 53 171 1327 11%
149 30 23 1994 149 757 53 285 1244 6%
120 30 23 1993 120 930 53 369 1472 9%
130 30 23 1992 130 1014 53 181 1378 7%
144 30 23 1991 144 747 53 315 1259 24%
106 30 23 1990 106 933 53 335 1427 22%
156 27 30 23 1989 156 816 80 13 1065 15%
139 7 30 23 1988 139 428 60 19 646 19%
174 15 30 23 1987 174 928 68 22 1192 13%
199 192 30 23 1986 199 973 245 0 1417 15%
148 248 150 30 1985 148 887 428 0 1463 17%
156 850 150 30 1984 156 930 1030 170 2286 20%
102 450 150 30 1983 102 888 630 235 1855 20%
146 116 150 30 1982 146 1217 296 335 1994 19%
155 294 150 30 1981 155 1506 474 209 2344 20%
85 368 150 30 1980 85 1346 548 249 2228 23%
171 200 26 30 1979 171 1116 256 138 1681 22%
157 63 26 30 1978 157 1112 119 177 1565 25%
172 1196 26 30 1977 172 1264 1252 247 2935 22%
183 472 26 30 1976 183 1260 528 186 2157 28%
177 169 23 30 1975 177 995 222 185 1579 23%
152 194 23 30 1974 152 1149 247 184 1732 25%
212 288 23 30 1973 212 1451 341 150 2154 23%
134 288 30 1972 134 1168 318 180 1800 21%
94 612 30 1971 94 913 642 250 1899 23%
137 990 30 1970 137 861 1020 200 2218 25%
302 700 30 1969 0 1364 1032 170 2566 25%
14 30 700 30 1968 14 1490 760 150 2414 26%
40 274 700 30 1967 40 825 1004 225 2094 24%
96 3046 700 30 1966 96 828 3776 225 4925 23%
70 3614 700 30 1965 70 595 4344 225 5234 21%
45 5952 700 30 1964 45 403 6682 225 7355 22%
94 2526 700 30 1963 94 278 3256 225 3853 21%
96 2334 700 30 1962 96 409 3064 225 3794 24%
145 3500 700 30 1961 145 438 4230 300 5113 27%
145 6444 700 30 1960 145 398 7174 375 8092 22%
1945 700 830 1959 472 3475 450 4397 24%
2103 700 830 1958 411 3633 450 4494 23%
796 700 830 1957 770 2326 450 3546 26%
600 700 830 1956 671 2130 450 3251 25%
329 700 130 1955 507 1159 450 2116 24%
776 700 130 1954 767 1606 450 2823 28%
1960–1969[153] 1970–99[158] 2000–2012[159] 2013–15[160] 2014[161] Arviat[162] 1996–2002[163]

2003–16[164]

1954–99[152] 1954–1985 cites Russian papers[153] NMFS cites Russian paper[146] Western[152] Okhotsk[146] Sources Total of columns at left, incomplete 1954–2016[165] Total of columns at left, incomplete 1954–84[153] 1987–90 Cook Inlet[166] 1990–2011[167] 2012–2015 +Cook Inlet[168][169] Total of other columns Greenland source 1954–1999, Beaufort source 2000–2012

Predation

During the winter, belugas commonly become trapped in the ice without being able to escape to open water, which may be several kilometres away.[170] Polar bears take particular advantage of these situations and are able to locate the belugas using their sense of smell. The bears swipe at the belugas and drag them onto the ice to eat them.[34] They are able to capture large individuals in this way; in one documented incident, a bear weighing between 150 and 180 kg was able to capture a beluga that weighed 935 kg.[171]

Killer whales hunt and eat both young and adult belugas.[34] They live in all the seas of the world and share the same habitat as belugas in the sub-Arctic region. Attacks on belugas by killer whales have been reported in the waters of Greenland, Russia, Canada and Alaska.[172][173] A number of killings have been recorded in Cook Inlet, and experts are concerned the predation by killer whales will impede the recovery of this sub-population, which has already been badly depleted by hunting.[172] The killer whales arrive at the beginning of August, but the belugas are occasionally able to hear their presence and evade them. The groups near to or under the sea ice have a degree of protection, as the killer whale's large dorsal fin, up to 2 m in length, impedes their movement under the ice and does not allow them to get sufficiently close to the breathing holes in the ice.[39] Beluga whale behavior under killer whale predation makes them vulnerable to hunters. When killer whales are present, large numbers of beluga whales congregate in the shallows for protection, which allows them to be hunted in droves.

Contamination

Russian scientists working on the White Whale Program place transmitters onto whales in Sea of Okhotsk

The beluga is considered an excellent sentinel species (indicator of environment health and changes), because it is long-lived, at the top of the food web, bears large amounts of fat and blubber, relatively well-studied for a cetacean, and still somewhat common.

Human pollution can be a threat to belugas' health when they congregate in river estuaries. Chemical substances such as DDT and heavy metals such as lead, mercury and cadmium have been found in individuals of the Saint Lawrence River population.[174] Local beluga carcasses contain so many contaminants, they are treated as toxic waste.[175] Levels of polychlorinated biphenyls between 240 and 800 ppm have been found in belugas' brains, liver and muscles, with the highest levels found in males.[176] These levels are significantly greater than those found in Arctic populations.[177] These substances have a proven adverse effect on these cetaceans, as they cause cancers, reproductive diseases and the deterioration of the immune system, making individuals more susceptible to pneumonias, ulcers, cysts, tumours and bacterial infections.[177] Although the populations that inhabit the river estuaries run the greatest risk of contamination, high levels of zinc, cadmium, mercury and selenium have also been found in the muscles, livers and kidneys of animals that live in the open sea.[178] The concentration of mercury in Beaufort Sea belugas tripled from the 1980s to the 1990s, but has decreased in Beaufort belugas as of the 21st century, possibly due to changes in dietary preference. Larger body sized belugas tend to have more mercury than smaller sized belugas, because they spend more time offshore, hunting prey such as cod and shrimp, which have more mercury.[179]

From a sample of 129 beluga adults from the Saint Lawrence River examined between 1983 and 1999, a total of 27% had suffered cancer.[180] This is a higher percentage than that documented for other populations of this species and is much higher than for other cetaceans and for the majority of terrestrial mammals; in fact, the rate is only comparable to the levels found in humans and some domesticated animals.[180] For example, the rate of intestinal cancer in the sample is much higher than for humans. This condition is thought to be directly related to environmental contamination, in this case by polycyclic aromatic hydrocarbons, and coincides with the high incidence of this disease in humans residing in the area.[180] The prevalence of tumours suggests the contaminants identified in the animals that inhabit the estuary are having a direct carcinogenic effect or they are at least causing an immunological deterioration that is reducing the inhabitants' resistance to the disease.[181]

Indirect human disturbance may also be a threat. While some populations tolerate small boats, most actively try to avoid ships. Whale-watching has become a booming activity in the St. Lawrence and Churchill River areas, and acoustic contamination from this activity appears to have an effect on belugas. For example, a correlation appears to exist between the passage of belugas across the mouth of the Saguenay River, which has decreased by 60%, and the increase in the use of recreational motorboats in the area.[182] A dramatic decrease has also been recorded in the number of calls between animals (decreasing from 3.4 to 10.5 calls/min to 0 or <1) after exposure to the noise produced by ships, the effect being most persistent and pronounced with larger ships such as ferries than with smaller boats.[183] Belugas can detect the presence of large ships (for example icebreakers) up to 50 km away, and they move rapidly in the opposite direction or perpendicular to the ship following the edge of the sea ice for distances of up to 80 km to avoid them. The presence of shipping produces avoidance behaviour, causing deeper dives for feeding, the break-up of groups, and asynchrony in dives.[184]

Pathogens

As with any animal population, a number of pathogens cause death and disease in belugas, including viruses, bacteria, protozoans and fungi, which mainly cause skin, intestinal and respiratory infections.[185]

Papillomaviruses, herpesviruses, and encephalitis caused by the protozoan Sarcocystis have been found in belugas in the Saint Lawrence River. Cases have been recorded of ciliate protozoa colonising the spiracle of certain individuals, but they are not thought to be pathogens or are not very harmful.[186]: 26, 303, 359  The bacterium Erysipelothrix rhusiopathiae, which probably comes from eating infected fish, poses a threat to belugas kept in captivity, causing anorexia and dermal plaques and lesions that can lead to sepsis.[186]: 26, 303, 359  This condition can cause death if it is not diagnosed and treated in time with antibiotics such as ciprofloxacin.[187][186]: 316–7  A study of infections caused by parasitic worms in a number of individuals of both sexes found the presence of larvae from a species from the genus Contracaecum in their stomachs and intestines, Anisakis simplex in their stomachs, Pharurus pallasii in their ear canals, Hadwenius seymouri in their intestines and Leucasiella arctica in their rectums.[188]

Relationship with humans

Captivity

Belugas were among the first whale species to be kept in captivity. The first beluga was shown at Barnum's Museum in New York City in 1861.[189] For most of the 20th century, Canada was the predominant source for belugas destined for exhibition. Throughout the early 1960s, belugas were taken from the St. Lawrence River estuary. In 1967, the Churchill River estuary became the main source from which belugas were captured. This continued until 1992, when the practice was banned.[156] Since then, Russia has become the largest provider.[156] Individuals are caught in the Amur River delta and the far eastern seas of the country, and then are either transported domestically to aquaria in Moscow, St. Petersburg and Sochi, or exported to foreign nations, including China[147] and formerly Canada.[156] Canada has now banned the practice of holding new animals in captivity.[190]

Beluga aims echolocation beam to choose a spot on an acoustic "touch screen" of hydrophones in the water

To provide some enrichment while in captivity, aquaria train belugas to perform behaviours for the public[191] and for medical exams, such as blood draws,[192] ultrasound,[193] providing toys,[191] and allowing the public to play recorded or live music.[194]

Between 1960 and 1992, the United States Navy carried out a program that included the study of marine mammals' abilities with echolocation, with the objective of improving the detection of underwater objects. The program started with dolphins, but a large number of belugas were also used from 1975 onwards.[195] The program included training them to carry equipment and material to divers working under water, the location of lost objects, surveillance of ships and submarines, and underwater monitoring using cameras held in their mouths.[195] A similar program was implemented by the Soviet Navy during the Cold War, in which belugas were also trained for antimining operations in Arctic waters.[174] It is possible this program continues within the Russian Navy, as on April 24, 2019, a tame beluga whale wearing a Russian equipment harness was found by fishermen near the Norwegian island of Ingøya.[196]

Belugas released from captivity have difficulties adapting to life in the wild, but if not fed by humans they may have a chance to join a group of wild belugas and learn to feed themselves, according to Audun Rikardsen of the University of Tromsø.[197]

In 2019, a sanctuary in Iceland was established for two belugas, Little White and Little Grey, that retired from a marine park in China. The Sea Life Trust Beluga Whale Sanctuary was created with support from Merlin Entertainments and Whale and Dolphin Conservation (WDC). Merlin bought the park in 2012, as part of an Australian chain, and it is one of their largest aquaria.[198] Merlin has a policy against captive cetaceans, so they sponsored a 32,000-square-metre sea pen as a sanctuary. The 12-year-old belugas, caught in Russia and raised in captivity, do not know how to live in the wild.[199][200] The cost is variously listed as ISK 3,000,000 (US$24,000) or US$27,000,000.[199] Merlin was owned until 2015 by Blackstone Group, which also owned SeaWorld[201] until selling its last stake in 2017 to a Chinese company which will use SeaWorld's expertise to expand in China;[202] SeaWorld still keeps belugas in captivity.

Photo of two white whales cheek-to-cheek with two trainers
Beluga whales in an aquarium interacting with trainers

Belugas are displayed across North America, Europe and Asia.[156] As of 2006, 58 belugas were held in captivity in Canada and the United States, and 42 deaths in US captivity had been reported up to that time. A single specimen costs up to US$100,000, although the price has now dropped to US$70,000.[203][204][156] As of January 2018, according to the nonprofit Ceta Base, which tracks belugas and dolphins under human care, there were 81 captive belugas in Canada and the United States, and unknown numbers in the rest of the world.[205][203][206] The beluga's popularity with visitors reflects its attractive colour and its range of facial expressions. The latter is possible because while most cetacean "smiles" are fixed, the extra movement afforded by the beluga's unfused cervical vertebrae allows a greater range of apparent expression.[49]

Most belugas found in aquaria are caught in the wild, as captive-breeding programs have not had much success so far.[207] For example, despite best efforts, as of 2010, only two male whales had been successfully used as stud animals in the Association of Zoos and Aquariums beluga population, Nanuq at SeaWorld San Diego and Naluark at the Shedd Aquarium in Chicago, US. Nanuq has fathered 10 calves, five of which survived birth.[208] Naluark at Shedd Aquarium has fathered four living offspring.[209] Naluark was relocated to the Mystic Aquarium in the hope that he would breed with two of their females,[210] but he did not, and in 2016 he was moved to SeaWorld Orlando.[211] The first beluga calf born in captivity in Europe was born in L'Oceanogràfic marine park in Valencia, Spain, in November 2006.[212] However, the calf died 25 days later after suffering metabolic complications, infections and not being able to feed properly.[213] A second calf was born on 16 November 2016, and was successfully maintained by artificial feeding based on enriched milk.[214]

In 2009 during a free-diving competition in a tank of icy water in Harbin, China, a captive beluga brought a cramp-paralysed diver from the bottom of the pool up to the surface by holding her foot in its mouth, saving the diver's life.[215][216]

Films which have publicised issues of beluga welfare include Born to Be Free,[217] Sonic Sea,[218] and Vancouver Aquarium Uncovered.[219]

Whale watching

Beluga at the confluence of the Saint Lawrence and Saguenay rivers

Whale watching has become an important activity in the recovery of the economies of towns in Quebec and Hudson Bay, near the Saint Lawrence and Churchill Rivers.[220] The best time to see belugas is during the summer, when they meet in large numbers in the estuaries of the rivers and in their summer habitats.[221] The animals are easily seen due to their high numbers and their curiosity regarding the presence of humans.[221]

However, the boats' presence poses a threat, as it distracts them from important activities such as feeding, social interaction and reproduction. In addition, the noise produced by the motors has an adverse effect on their auditory function and reduces their ability to detect their prey, communicate and navigate.[222] To protect these marine animals during whale-watching activities, the US National Oceanic and Atmospheric Administration has published a "Guide for observing marine life". The guide recommends boats carrying the whale watchers keep their distance from the cetaceans and it expressly prohibits chasing, harassing, obstructing, touching, or feeding them.[223]

Some regular migrations do occur into Russian EEZ of Sea of Japan such as to Rudnaya Bay, where diving with wild belugas became a less-known but popular attraction.[224]

On 25 September 2018, a beluga was sighted in the Thames Estuary and near towns along the Kent side of the Thames, being nicknamed Benny by newspapers. The whale, who was noticed by conservationists to be traveling alone, appeared to be separated from the rest of its group, and is thought to be a lost individual. Subsequent sightings were reported on the following day,[225] and continued into 2019, when local experts concluded that Benny had left the estuary.[226]

On 13 May 2021, two beluga whales were sighted in waters around Prince Edward Island, Atlantic Canada. One whale entered the Charlottetown Harbour and travelled up the Hillsborough River to Mount Stewart, Prince Edward Island. As of 30 May the whale was still sighted in the area.[227][228]

In August 2022, a beluga was found on the river Seine, France.[229]

Human speech

Male belugas in captivity can mimic the pattern of human speech, several octaves lower than typical whale calls.[230] One captive male beluga named NOC, pronounced "No-see", caused a diver in a tank with him to surface by imitating orders to get out of the water. Subsequent recordings confirmed that NOC had become skilled at imitating the patterns and frequency of human speech, and intentionally altered his normal methods of vocalization to achieve these sounds. After several years, he ceased making these sounds.[231]

Conservation status

Video explaining conservation efforts in the Sea of Okhotsk, Russia
Photo of stamp showing two adults and one juvenile, swimming
Pictured on Faroe Islands stamp

Prior to 2008, the beluga was listed as "vulnerable" by the International Union for Conservation of Nature (IUCN), a higher level of concern. The IUCN cited the stability of the largest sub-populations and improved census methods that indicate a larger population than previously estimated. In 2008, the beluga was reclassified as "near threatened" by the IUCN due to uncertainty about threats to their numbers and the number of belugas over parts of its range (especially the Russian Arctic), and the expectation that if current conservation efforts cease, especially hunting management, the beluga population is likely to qualify for "threatened" status within five years.[232] In June 2017, its status was reassessed to "least concern".[2]

There are about 21 sub-populations of beluga whales and it is estimated that 200,000 individuals still exist, which are listed as Least Concern on the IUCN Red List.[233] However, the nonmigratory Cook Inlet sub-population off the Gulf of Alaska is a separate sub-population that is listed as "critically endangered" by the IUCN as of 2006[2] and as "endangered" under the Endangered Species Act as of October 2008.[234][235][236][2] This was primarily due to unregulated overharvesting of beluga whales prior to 1998. The population has remained relatively consistent, though the reported harvest has been small. As of 2016, the estimated abundance of the endangered Cook Inlet population was 293 individuals.[237] The most recent estimate in 2018 by NOAA Fisheries suggested that the population declined to 279 individuals.[237]

Despite beluga whales not being threatened overall, sub-populations are being listed as critically endangered and are facing increased mortality from human actions. For example, even though commercial hunting is now banned due to the Marine Mammal Protection Act, beluga whales are still being hunted to preserve the livelihood of native Alaskan communities.[238] The IUCN and NOAA Fisheries cite habitat degradation, oil and gas drilling, underwater noise, harvesting for consumption and climate change as threats to the prolonged survival of beluga whale sub-populations.[238]

Beluga whale populations are currently being harvested at levels which are not sustainable and it is difficult for those harvesting beluga whales to know which sub-population they are from.[239] Because there is little protection of sub-populations, harvest will need to be managed to ensure sub-populations will survive long into the future to discover the importance of their migratory patterns and habitat use.

Beluga whales, like most other arctic species, are being faced with alteration of their habitat due to climate change and melting arctic ice.[239] Changes in sea-ice has resulted in changes in the area used by Chukchi belugas, since belugas spent less time in close proximity to the ice edge in comparison to previous years. Additionally, Chukchi Sea belugas spent a prolonged amount of time in Barrow Canyon on the Beaufort Sea side in October. Chukchi sea belugas also appear to be spending more time in deeper water presently, as opposed to the 1990s. Belugas also seemed to be taking longer and deeper dives. A hypothesis as to why this might be the case is an up-welling of rich Atlantic water in the Beaufort Sea may result in concentrated prey items like Arctic cod. The fall migration of Chukchi belugas is later, although summer and fall habitat selection has not changed. Fall migration of Chukchi belugas appears to be correlated with Beaufort Sea freeze up.[240]

It is hypothesized that beluga whales utilize ice as protection from killer whale predation or for feeding on schools of fish.[241] Killer whales can penetrate further into the Arctic and remain in arctic waters for a longer period of time due to reductions in sea ice. For example, residents in Kotzebue, have reported that killer whales have been sighted more frequently in Kotzebue Sound.

As annual ice cover declines, humans may gain access and disrupt beluga whale habitats.[241] For example, the number of vessels in the Arctic for gas and oil exploration, fishing, and commercial shipping has already increased and a continuous trend may lead to higher risks of injuries and deaths for beluga whales.[241]

In addition, it is possible that beluga whales may face by an increased risk of entrapment from leads and cracks freezing, due to the erratic nature of climate change. Abrupt changes in weather can cause these leads and cracks to freeze ultimately causing the whales to die of suffocation.[239] An increase in urbanization will likely lead to higher concentrations of toxic pollutants in the blubber of beluga whales since they are at the top of the food chain and are affected by bio-accumulation.[241] Loss of sea ice and a change in ocean temperatures may also affect the distribution and composition of prey or affect their competition.[241] There is also some evidence that climate change can affect males and females differently. Since 1983, belugas have been increasingly scarce in Kotzebue sound. However, in 2007, several hundred whales were spotted in the sound, with over 90% of the whales being male. However, more research needs to be conducted to understand how climate change affects beluga whale sex aggregation.[242]

The US Congress passed the Marine Mammal Protection Act of 1972, outlawing the persecution and hunting of all marine mammals within US coastal waters. The act has been amended a number of times to permit subsistence hunting by native peoples, temporary capture of restricted numbers for research, education and public display, and to decriminalise the accidental capture of individuals during fishing operations.[243] The act also states that all whales in US territorial waters are under the jurisdiction of the National Marine Fisheries Service, a division of NOAA.[243]

To prevent hunting, belugas are protected under the 1986 International Moratorium on Commercial Whaling; however, hunting of small numbers of belugas is still allowed. Since it is very difficult to know the exact population of belugas because their habitats include inland waters away from the ocean, they easily come in contact with oil and gas development centres. To prevent whales from coming in contact with industrial waste, the Alaskan and Canadian governments are relocating sites where whales and waste come in contact.

The beluga whale is listed on appendix II[244] of the Convention on the Conservation of Migratory Species of Wild Animals (CMS). It is listed on appendix II[244] as it has an unfavourable conservation status or would benefit significantly from international co-operation organised by tailored agreements. All toothed whales are protected under the CITES that was signed in 1973 to regulate the international import and export of certain species.[245]

The isolated beluga population in the Saint Lawrence River has been legally protected since 1983.[246] In 1988 Canadian Department of Fisheries and Oceans and Environment Canada, a governmental agency that supervises national parks, implemented the Saint Lawrence Action Plan[247] with the aim of reducing industrial contamination by 90% by 1993; as of 1992, the emissions had been reduced by 59%. The population of the St. Lawrence belugas decreased from 10,000 in 1885 to around 1,000 in the 1980 and around 900 in 2012.[248]

Conservation research in managed care facilities

As of 2015, there were 33 individuals housed in managed care facilities in North America.[249] These facilities are members of the Association of Zoos and Aquariums, aiming to understand the complex reproductive physiology of this species to improve their conservation. With the extreme difficulty of studying beluga whales in the wild and the lack of ability to collect biological samples or perform examinations on individuals, managed care facilities play a critical role.[250]

Managed care facilities in North America have been able to work cooperatively to build upon the research of beluga whale reproduction and have made remarkable advances. Using operant conditioning, these facilities have trained beluga whales for voluntary biological sampling and examinations. Blood,[251] urine,[252] and blow samples[253] have all been collected for longitudinal hormone monitoring studies.

In addition, beluga whales have undergone semen collection,[249] body temperature data collection,[251] reproductive tract examinations via transabdominal ultrasound, and endoscopic exams.[254] With new technology, the reproductive characteristics of both the female and male beluga whale have been accurately described and has benefited captive breeding programs globally.

As more research is done, the management of beluga whales in managed care facilities can be greatly improved and may even help develop other cetacean breeding and contraceptive programs, such as that of the bottlenose dolphin.[249] Through fetal health and gestation monitoring, facilities can be more equipped to deal with pregnant animals as well.[251] While training has been done to collect beluga whale semen, only few facilities have been able to successfully do so as both saltwater and urine contamination need to be avoided.[255] Improvement of this process will help increase the success of captive breeding programs.

Cultural references

Engravings on beluga bones

Pour la suite du monde, is a Canadian documentary film released in 1963 about traditional beluga hunting carried out by the inhabitants of L'Isle-aux-Coudres on the Saint Lawrence River.[256]

The children's singer Raffi released an album called Baby Beluga in 1980. The album starts with the sound of whales communicating, and includes songs representing the ocean and whales playing. The song "Baby Beluga" was composed after Raffi saw a recently born beluga calf in Vancouver Aquarium.[257]

The fuselage design of the Airbus Beluga, one of the world's biggest cargo planes, is very similar to that of a beluga. It was originally called the Super Transporter, but the nickname Beluga became more popular and was then officially adopted.[258] The company paints the 2019 Beluga XL version to emphasize the plane's similarity to the Beluga whale.[259]

Airbus BelugaXL

In the 2016 Disney/Pixar animated film Finding Dory, the sequel to Finding Nemo (2003), the character Bailey is a beluga whale and its echolocation abilities are a significant part of the plot.[260][261]

See also

References

  1. ^ a b c Mead, J. G.; Brownell, R. L. Jr. (2005). "Order Cetacea". In Wilson, D. E.; Reeder, D. M. (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. p. 735. ISBN 978-0-8018-8221-0. OCLC 62265494.
  2. ^ a b c d Lowry, L.; Reeves, R.; Laidre, K. (2017). "Delphinapterus leucas". IUCN Red List of Threatened Species. 2017: e.T6335A50352346. doi:10.2305/IUCN.UK.2017-3.RLTS.T6335A50352346.en. Retrieved 12 November 2021.
  3. ^ "Appendices | CITES". cites.org. Archived from the original on 5 December 2017. Retrieved 14 January 2022.
  4. ^ "beluga". Oxford English Dictionary (Online ed.). Oxford University Press. doi:10.1093/OED/4456975553. (Subscription or participating institution membership required.)
  5. ^ Bradford, Alina (20 July 2016). "Facts About Beluga Whales". Live Science. Archived from the original on 3 May 2019. Retrieved 12 June 2019.
  6. ^ "Global Review of the Conservation Status of Monodontid Stocks | Scientific Publications Office". spo.nmfs.noaa.gov. Archived from the original on 25 November 2020. Retrieved 2 January 2021.
  7. ^ a b Vacquié-Garcia, J; Lydersen, C; Marques, TA; Andersen, M; Kovacs, KM (27 February 2020). "First abundance estimate for white whales Delphinapterus leucas in Svalbard, Norway". Endangered Species Research. 41: 253–263. doi:10.3354/esr01016. hdl:10023/19740.
  8. ^ "Baby Beluga, Smithsonian Ocean". Smithsonian Institution. Archived from the original on 3 March 2021. Retrieved 20 January 2021.
  9. ^ Gibbons, Whit (27 May 2012). "Ecoview | BELUGA WHALES ARE COOL". Savannah River Ecology Laboratory, University of Georgia. Archived from the original on 15 April 2021. Retrieved 20 January 2021.
  10. ^ Arnold, P. "Irrawaddy Dolphin Orcaella brevirostris". Encyclopedia of Marine Mammals. p. 652.
  11. ^ Grétarsdóttir, S.; Árnason, Ú. (1992). "Evolution of the common cetacean highly repetitive DNA component and the systematic position of Orcaella brevirostris". Journal of Molecular Evolution. 34 (3): 201–208. Bibcode:1992JMolE..34..201G. doi:10.1007/BF00162969. PMID 1588595. S2CID 8591445.
  12. ^ a b c d e f O'Corry-Crowe, G. "Beluga Whale Delphinapterus leucas". Encyclopedia of Marine Mammals. pp. 94–99.
  13. ^ Heide-Jørgensen, Mads P.; Reeves, Randall R. (1993). "Description of an Anomalous Monodontid Skull from West Greenland: A Possible Hybrid?". Marine Mammal Science. 9 (3): 258–68. Bibcode:1993MMamS...9..258H. doi:10.1111/j.1748-7692.1993.tb00454.x.
  14. ^ a b c d Leatherwood, Stephen; Reeves, Randall R. (1983). The Sierra Club Handbook of Whales and Dolphins. Sierra Club Books. p. 320. ISBN 978-0-87156-340-8.
  15. ^ "Japanese whale whisperer teaches beluga to talk". meeja.com.au. 16 September 2008. Archived from the original on 13 January 2009. Retrieved 16 September 2008.
  16. ^ Kusma, Stephanie (23 October 2012). "Ein "sprechender" Beluga-Wal" [A "talking" Beluga whale]. Neue Zürcher Zeitung (in German). Archived from the original on 24 October 2012. Retrieved 25 October 2012.
  17. ^ a b Waddell, Victor G.; Milinkovitch, Michel C.; Bérubé, Martine; Stanhope, Michael J. (2000). "Molecular Phylogenetic Examination of the Delphinoidea Trichotomy: Congruent Evidence from Three Nuclear Loci Indicates That Porpoises (Phocoenidae) Share a More Recent Common Ancestry with White Whales (Monodontidae) Than They Do with True Dolphins (Delphinidae)". Molecular Phylogenetics and Evolution. 15 (2): 314–8. Bibcode:2000MolPE..15..314W. doi:10.1006/mpev.1999.0751. PMID 10837160.
  18. ^ Arnason, U.; Gullberg, A. (1996). "Cytochrome b nucleotide sequences and the identification of five primary lineages of extant cetaceans". Molecular Biology and Evolution. 13 (2): 407–17. doi:10.1093/oxfordjournals.molbev.a025599. PMID 8587505.
  19. ^ Jones, Steven J.M.; et al. (2017). "The Genome of the Beluga Whale (Delphinapterus leucas)". Genes. 8 (12): 378. doi:10.3390/genes8120378. PMC 5748696. PMID 29232881.
  20. ^ Barnes, Lawrence G. Fossil odontocetes (Mammalia: Cetacea) from the Almejas Formation, Isla Cedros, Mexico. University of California, Museum of Paleontology. p. 46. ASIN B0006YRTU4.
  21. ^ "Denebola brachycephala". ZipcodeZoo.com. Archived from the original on 20 August 2012. Retrieved 1 August 2010.
  22. ^ a b Vélez-Juarbe, J.; Pyenson, N. D. (2012). "Bohaskaia monodontoides, a new monodontid (Cetacea, Odontoceti, Delphinoidea) from the Pliocene of the western North Atlantic Ocean". Journal of Vertebrate Paleontology. 32 (2): 476–484. Bibcode:2012JVPal..32..476V. doi:10.1080/02724634.2012.641705. S2CID 55606151.
  23. ^ Barnes, L. G. (1977). "Outline of Eastern North Pacific Fossil Cetacean Assemblages". Systematic Zoology. 25 (4): 321–343. doi:10.2307/2412508. JSTOR 2412508.
  24. ^ Bianucci, Giovanni; Pesci, Fabio; Collareta, Alberto; Tinelli, Chiara (2019). "A new Monodontidae (Cetacea, Delphinoidea) from the lower Pliocene of Italy supports a warm-water origin for narwhals and white whales". Journal of Vertebrate Paleontology. 39 (3): e1645148. Bibcode:2019JVPal..39E5148B. doi:10.1080/02724634.2019.1645148. hdl:11568/1022436. S2CID 202018525.
  25. ^ Perrin, William F.; Würsig, Bernd G.; Thewissen, J. G. M. (2009). Encyclopaedia of marine mammals (2 ed.). Academic Press. p. 214. ISBN 978-0-12-373553-9.
  26. ^ "Charlotte, The Vermont Whale – An Electronic Museum". University of Vermont. Archived from the original on 19 December 2010. Retrieved 2 August 2010.
  27. ^ Wright, Wesley (2009). "Our State Fossil". University of Vermont. Archived from the original on 10 August 2016. Retrieved 23 August 2016.
  28. ^ Burns J.J.; Seaman G.A. (1983). "Investigations of belukha whales in coastal waters of western and northern Alaska, 1982–1983: marking and tracking of whales in Bristol Bay". Biology and Ecology. US Dept Commer, NOAA, OCSEAP Final Rep, II. 56: 221–357. OSTI 6361651.
  29. ^ Goren, Arthur D.; Brodie, Paul F.; Spotte, Stephen; Ray, G. Carleton; Kaufman, H. W.; Gwinnett, A. John; Sciubba, James J.; Buck, John D. (1987). "Growth Layer Groups (GLGs) in the Teeth of an Adult Belukha Whale (Delphinapterus leucas) of Known Age: Evidence for Two Annual Layers". Marine Mammal Science. 3 (1): 14–21. Bibcode:1987MMamS...3...14G. doi:10.1111/j.1748-7692.1987.tb00148.x.
  30. ^ Stewart, R.E.A.; Campana, S.E.; Jones, C.M.; Stewart, B.E. (2006). "Bomb radiocarbon dating calibrates beluga (Delphinapterus leucas) age estimates". Can. J. Zool. 84 (12): 1840–1852. doi:10.1139/Z06-182.
  31. ^ Suydam, Robert S.; Lowry, Lloyd F.; Frost, Kathy J.; O'Corry-Crowe, Greg M.; Pikok, Danny (1 January 2001). "Satellite Tracking of Eastern Chukchi Sea Beluga Whales into the Arctic Ocean". Arctic. 54 (3). doi:10.14430/arctic784.
  32. ^ a b c Convention on Migratory Species – CMS. "Delphinapterus leucas (Pallas, 1776)". Archived from the original on 21 August 2011. Retrieved 3 August 2010.
  33. ^ a b c d e Shirihai, H. & Jarrett, B. (2006). Whales, Dolphins and Other Marine Mammals of the World. Princeton: Princeton Univ. Press. pp. 97–100. ISBN 978-0-691-12757-6.
  34. ^ a b c Reeves, R.; Stewart, B.; Clapham, P. & Powell, J. (2003). Guide to Marine Mammals of the World. New York: A.A. Knopf. pp. 318–321. ISBN 978-0-375-41141-0.
  35. ^ "Aquatic Species at Risk – Beluga Whale (St. Lawrence Estuary population)". Fisheries and Oceans Canada. Archived from the original on 11 December 2011.
  36. ^ Stewart BE, Stewart RE (1989). "Delphinapterus leucas" (PDF). Mammalian Species (336): 1–8. doi:10.2307/3504210. JSTOR 3504210. S2CID 254005748. Archived from the original (PDF) on 15 June 2013. Retrieved 22 September 2011.
  37. ^ a b c d e Ridgway, S. & Harrison, R. (1981). Handbook of Marine Mammals (6 ed.). San Diego: Academic Press Limited. p. 486. ISBN 978-0-12-588506-5. Archived from the original on 14 May 2021. Retrieved 12 July 2018.
  38. ^ a b c d e "Beluga Whales – Physical Characteristics". Sea World.org. Archived from the original on 19 June 2010. Retrieved 30 July 2010.
  39. ^ a b c d e Paine, S. (1995). The World of the Arctic Whales. San Francisco: Sierra Club. ISBN 978-0-87156-957-8. Archived from the original on 14 May 2021. Retrieved 14 April 2018.
  40. ^ Sergeant, D. E. & Brodie, P. F. (1969). "Body Size in White Whales, Delphinapterus leucas". Journal of the Fisheries Research Board of Canada. 26 (10): 2561–2580. doi:10.1139/f69-251.
  41. ^ United Nations Environment Programme – Conservation of Migratory Species of Wild Animals (2006). Review of small cetaceans: distribution, behaviour, migration and threats: 177 (Marine mammal action plan/regional seas reports and studies). UNEP/CMS. p. 356. ISBN 978-3-937429-02-1.
  42. ^ a b "Delphinapterus leucas – Morphology, Physical Description". Encyclopedia of Life. Archived from the original on 20 February 2023. Retrieved 3 August 2010.
  43. ^ a b c d Friedman W. R. (June 2006). "Environmental Adaptations of the Beluga Whale (Delphinapterus leucas)" (PDF). Cognitive Science. 143. Archived (PDF) from the original on 30 October 2012.
  44. ^ a b St. Aubin, D. J.; Smith, T. G.; Geraci, J. R. (1990). "Seasonal Epidermal Molt in Beluga Whales, Delphinapterus leucas". Canadian Journal of Zoology. 68 (2): 339–367. doi:10.1139/z90-051.
  45. ^ a b c d Haley, Delphine (1986). Marine Mammals of Eastern North Pacific and Arctic Waters (2 ed.). Seattle: Pacific Search Press. ISBN 978-0-931397-14-1.[page needed]
  46. ^ a b c d e f "Beluga Whales – Communication and Echolocation". Sea World.org. Archived from the original on 19 June 2010. Retrieved 30 July 2010.
  47. ^ Turl, C.W. (1990). T.G. Smith; D.J. St. Aubin; J.R. Geraci. (eds.). "Echolocation abilities of the beluga, Delphinapterus leucas: a review and comparison with the bottlenose dolphin, Tursiops truncatus". Can. Bull. Fish. Aquat. Sci. 224: 119–128.
  48. ^ Litchfield, Carter; Ackman, R. G.; Sipos, J. C.; Eaton, C. A. (1971). "Isovaleroyl triglycerides from the blubber and melon oils of the beluga whale (Delphinapterus leucas)". Lipids. 6 (9): 674–81. doi:10.1007/BF02531529. PMID 5141491. S2CID 4023319.
  49. ^ a b Bonner, W.N. (1980). Whales. Poole, England: Abe Books. pp. 17, 23–24. ISBN 978-0-7137-0887-5.
  50. ^ a b c d e f Nowak, Ronald M. (1991). Walker's Mammals of the World. Vol. 2 (5 ed.). Baltimore: The Johns Hopkins University Press. ISBN 978-0-8018-5789-8. Archived from the original on 14 May 2021. Retrieved 14 April 2018.[page needed]
  51. ^ The National Oceanic and Atmospheric Administration's National Marine Fisheries Service – Alaska Regional Office (2 October 2018). "Beluga Whales". Archived from the original on 4 June 2010. Retrieved 3 August 2010.
  52. ^ Enchanted Learning. "Blowhole". Archived from the original on 5 March 2010. Retrieved 6 August 2010.
  53. ^ a b Aubin DJST (1989). "Thyroid function and epidermal growth in beluga whales, Delphinapterus leucas". Diss Abst Int Pt B Sci and Eng. 50 (1).
  54. ^ Mikaelian, I.; Labelle, P.; Kopal, M.; De Guise, S.; Martineau, D. (2003). "Adenomatous Hyperplasia of the Thyroid Gland in Beluga Whales (Delphinapterus leucas) from the St. Lawrence Estuary and Hudson Bay, Quebec, Canada". Veterinary Pathology. 40 (6): 698–703. doi:10.1354/vp.40-6-698. PMID 14608025. S2CID 34734748.
  55. ^ Kasting NW, Adderley SA, Safford T, Hewlett KG (1989). "Thermoregulation in beluga (Delphinapterus leucas) and killer (Orcinus orca) whales". Physiological Zoology. 62 (3): 687–701. doi:10.1086/physzool.62.3.30157921. JSTOR 30157921. S2CID 86884106.
  56. ^ a b Belkovitch, V. M.; Shekotov, M. N. (1993). The Belukha Whale: Natural Behavior and Bioacoustics (PDF). Woods Hole, MA: Woods Hole Oceanographic Inst. Archived (PDF) from the original on 7 April 2014.
  57. ^ Fay, R. R. (1988). Hearing in Vertebrates: a Psychophysics Databook. Vol. 86. Winnetka IL: Hill-Fay Associates. p. 621. Bibcode:1989ASAJ...86.2044F. doi:10.1121/1.398550. ISBN 978-0-9618559-0-1. Archived from the original on 14 May 2021. Retrieved 12 July 2018. {{cite book}}: |journal= ignored (help)
  58. ^ Olson, Harry F (1967). Music, Physics and Engineering. Dover Journals. p. 249. ISBN 978-0-486-21769-7. Archived from the original on 14 May 2021. Retrieved 12 July 2018.
  59. ^ a b Sea World.org. "Beluga Whales – Senses". Archived from the original on 19 June 2010. Retrieved 30 July 2010.
  60. ^ a b c d Herman, Louis (1988). Cetacean Behavior: Mechanisms and Functions. Nueva York: John Wiley and Sons. p. 480. ISBN 978-0-89464-272-2. Archived from the original on 14 May 2021. Retrieved 12 July 2018.
  61. ^ a b c d Katona, Steven K.; Valerie Rough & David T. Richardson (1993). Field Guide to Whales, Porpoises, and Seals from Cape Cod to Newfoundland (4 ed.). Smithsonian Institution Press. p. 336. ISBN 978-1-56098-333-0.
  62. ^ Illustrated Encyclopedia of North American Mammals: A Comprehensive Guide to Mammals of North America. MobileReference. 2009. ISBN 978-1-60501-279-7.
  63. ^ Slijper, E. J. (1979). Whales (2 ed.). Ithaca, Nueva York: Cornell University Press. p. 511. ISBN 978-0-8014-1161-8. Archived from the original on 14 May 2021. Retrieved 12 July 2018.
  64. ^ Jefferson TA, Leatherwood S, Webber MA (1993). FAO Species identification guide. Marine mammals of the world (PDF). UNEP / FAO, Rome. p. 320. Archived from the original (PDF) on 2 March 2013.
  65. ^ a b c d MacDonald, David (2006). "Beluga whale". The Encyclopedia of Mammals. Nueva York: Facts on File, Inc. p. 895. ISBN 978-0-87196-871-5.
  66. ^ Sjare, Becky L. & Thomas G. Smith (1986). "The Relationship Between Behavioral Activity and Underwater Vocalizations of the White Whale, Delphinapterus leucas". Canadian Journal of Zoology. 64 (12): 2824–2831. doi:10.1139/z86-406.
  67. ^ a b Sea World.org. "Beluga Whales – Behavior". Archived from the original on 19 June 2010. Retrieved 30 July 2010.
  68. ^ Georgia Aquarium. "Beluga Whale". Archived from the original on 2 October 2008. Retrieved 12 October 2008.
  69. ^ Alaska Geographic Society (1979). Alaska Whales and Whaling. Edmonds, Washington: Alaska Northwest Publishing Co. Archived from the original on 6 November 2012. Retrieved 12 September 2012.
  70. ^ Smith, T. G. & Sleno, G. A. (1986). "Do White Whales, Delphinapterus leucas, Carry Surrogates in Response to Early Loss of Their Young". Canadian Journal of Zoology. 64 (7): 1581–1582. doi:10.1139/z86-237.
  71. ^ Fish, FE (1998). "Comparative kinematics and hydrodynamics of odontocete cetaceans: Morphological and ecological correlates with swimming performance". The Journal of Experimental Biology. 201 (Pt 20): 2867–2877. doi:10.1242/jeb.201.20.2867. PMID 9739069.
  72. ^ "Georgia Aquarium – Beluga Whale". Archived from the original on 2 October 2008. Retrieved 12 October 2008.
  73. ^ Sea World.org. "Beluga Whales – Adaptations for an Aquatic Environment". Archived from the original on 19 June 2010. Retrieved 30 July 2010.
  74. ^ Ridgway, Sam H.; Carder, Donald A.; Kamolnick, Tricia; Smith, Robert R.; Schlundt, Carolyn E.; Elsberry, Wesley R. (2001). "Hearing and whistling in the deep sea: Depth influences whistle spectra but does not attenuate hearing by white whales (Delphinapterus leucas) (Odontoceti, Cetacea)". The Journal of Experimental Biology. 204 (Pt 22): 3829–41. doi:10.1242/jeb.204.22.3829. hdl:1969.1/180722. PMID 11807101.
  75. ^ a b c d Heide-Jørgensen, M. P.; Richard, P. R.; Rosing-Asvid, A. (March 1998). "Dive Patterns of Belugas (Delphinapterus leucas) in Waters near Eastern Devon Island". Arctic. 51 (1): 17–26. doi:10.14430/arctic1041. JSTOR 40511799. S2CID 52905886.
  76. ^ Hauser, DDW; Laidre, KL; Parker-Stetter, SL; Horne, JK; Suydam, RS; Richard, PR (15 December 2015). "Regional diving behavior of Pacific Arctic beluga whales Delphinapterus leucas and possible associations with prey". Marine Ecology Progress Series. 541: 245–264. Bibcode:2015MEPS..541..245H. doi:10.3354/meps11530.
  77. ^ "Delphinapterus leucas: Beluga Whale". Marine Bio. Archived from the original on 3 March 2014. Retrieved 26 August 2008.
  78. ^ a b c Ridgway, Sam H (1972). Mammals of the Sea. Biology and Medicine. Springfield, Illinois: Charles C. Thomas. p. 812. ISBN 978-0-398-02389-8. Archived from the original on 14 May 2021. Retrieved 12 July 2018.
  79. ^ Ridgway, S. H.; Bowers; Miller; Schultz; Jacobs; Dooley; et al. (1984). "Diving and Blood Oxygen in the White Whale". Canadian Journal of Zoology. 6 (11): 2349–2351. doi:10.1139/z84-344.
  80. ^ Noren, S.R.; Williams, T.M. (2000). "Body size and skeletal muscle myoglobin of cetaceans: Adaptations for maximizing dive duration". Comparative Biochemistry and Physiology A. 126 (2): 181–91. doi:10.1016/S1095-6433(00)00182-3. PMID 10936758.
  81. ^ Dueck L. (2014). "3.2 Habits – 3.2.1 Diving Characteristics and Sightability Estimates of Eastern Arctic Bowhead Whales Based on Satellite-Linked Telemetry". The Fisheries and Oceans Canada. Archived from the original on 30 January 2015. Retrieved 30 January 2015.
  82. ^ Loseto LL, Stern GA, Connelly TL, Deibel D, Gemmill B, Prokopowicz A, Fortier L, Ferguson SH (2009). "Summer diet of beluga whales inferred by fatty acid analysis of the eastern Beaufort Sea food web". J Exp Mar Biol Ecol. 374 (1): 12–18. Bibcode:2009JEMBE.374...12L. doi:10.1016/j.jembe.2009.03.015. Archived from the original on 23 October 2020.
  83. ^ Heide-Jorgensen, M.P.; Teilmann, J (1994). "Growth, reproduction, age structure and feeding habits of white whales (Delphinapterus leucas) in West Greenland waters". Meddr Gronland, Biosci. 39: 195–212. doi:10.7146/mogbiosci.v39.142550.
  84. ^ Frost, K.J. & Lowry, L.F. (1981). "Trophic importance of some marine gadids in Northern Alaska and their body-otolith size relationships". Fish. Bull. 79: 187–192. Archived from the original on 18 April 2024. Retrieved 10 January 2019.
  85. ^ a b Lentifer, J (1988). Selected Marine Mammals of Alaska: Species Accounts with Research and Management Recommendations. Marine Mammals Commission. ASIN B000102908.[page needed]
  86. ^ Perez, Michael A – NOAA (1990). NOAA Technical Memorandum NMFS F/NWC-186. Review of Marine Mammal Population and Prey Information for Bering Sea Ecosystem Studies. NOAA.
  87. ^ Breton-Honeyman, K.; Hammill, M.O.; Furgal, C.M.; Hickie, B. (2016). "Inuit Knowledge of beluga whale (Delphinapterus leucas) foraging ecology in Nunavik (Arctic Quebec), Canada". Canadian Journal of Zoology. 94 (10): 713–726. doi:10.1139/cjz-2015-0259. hdl:1807/73843.
  88. ^ Quakenbush, Lori T.; Suydam, Robert S.; Brown, Anna L.; Lowry, Lloyd F.; Frost, Kathryn J.; Mahoney, Barbara A. (2015). "Diet of beluga whales, Delphinapterus leucas, in Alaska from stomach contents, March–November". Marine Fisheries Review. 77 (1): 70–84. doi:10.7755/MFR.77.1.7.
  89. ^ Sea World.org. "Beluga Whales – Diet and Eating Habits". Archived from the original on 12 July 2010. Retrieved 30 July 2010.
  90. ^ Kastelein, R. A.; Boxsel, M. van; Wiepkema, P. R.; Ford, J.; Berghout, E. (1994). "Food consumption, growth and reproduction of Belugas (Delphinapterus leucas) in human care" (PDF). Aquatic Mammals. 20 (2): 81–97. Archived from the original (PDF) on 5 August 2019. Retrieved 27 January 2020.
  91. ^ Katona, Steven K.; Valerie Rough & David T. Richardson. (1983). A Field Guide to the Whales, Porpoises and Seals of the Gulf of Maine and Eastern Canada. New York: Charles Scribner's Sons. p. 255. ISBN 978-0-684-17902-5.
  92. ^ Lentifer, Jack W. (1988). Selected Marine Mammals of Alaska: Species Accounts with Research and Management Recommendations. Washington, D.C.: Marine Mammals Commission. ASIN B000102908. OCLC 18060784.[page needed]
  93. ^ a b Suydam, Robert Scott (2009). "Age, growth, reproduction, and movements of beluga whales (Delphinapterus leucas) from the eastern Chukchi Sea" (PDF). University of Washington. Archived (PDF) from the original on 19 September 2011. Retrieved 4 August 2008.
  94. ^ Ellis, Samuel; Franks, Daniel W.; Nattrass, Stuart; Currie, Thomas E.; Cant, Michael A.; Giles, Deborah; Balcomb, Kenneth C.; Croft, Darren P. (27 August 2018). "Analyses of ovarian activity reveal repeated evolution of post-reproductive lifespans in toothed whales". Scientific Reports. 8 (1): 12833. Bibcode:2018NatSR...812833E. doi:10.1038/s41598-018-31047-8. PMC 6110730. PMID 30150784.
  95. ^ Ellis, Samuel; Franks, Daniel W.; Nattrass, Stuart; Currie, Thomas E.; Cant, Michael A.; Giles, Deborah; Balcomb, Kenneth C.; Croft, Darren P. (27 August 2018). "Analyses of ovarian activity reveal repeated evolution of post-reproductive lifespans in toothed whales". Scientific Reports. 8 (1): 12833. Bibcode:2018NatSR...812833E. doi:10.1038/s41598-018-31047-8. PMC 6110730. PMID 30150784.
  96. ^ Williams, Shavon. "Delphinapterus leucas". Animal Diversity Web. Archived from the original on 5 November 2020. Retrieved 12 October 2020.
  97. ^ Robeck, Todd R.; Monfort, Steven L.; Calle, Paul P.; Dunn, J. Lawrence; Jensen, Eric; Boehm, Jeffrey R.; Young, Skip; Clark, Steven T. (2005). "Reproduction, Growth and Development in Captive Beluga (Delphinapterus leucas)". Zoo Biology. 24 (1): 29–49. doi:10.1002/zoo.20037.
  98. ^ Cosens, S. & Dueck, L. (June 1990). "Spring Sightings of Narwhal and Beluga Calves in Lancaster Sound, N.W.T" (PDF). Arctic. 43 (2): 1–2. doi:10.14430/arctic1602. Archived (PDF) from the original on 28 October 2008.
  99. ^ Animal Diversity Web – Museum of Zoology, University of Michigan. "Delphinapterus leucas". Archived from the original on 6 June 2011. Retrieved 30 July 2010.
  100. ^ Sea World.org. "Beluga Whales – Birth and Care of the Young". Archived from the original on 19 June 2010. Retrieved 30 July 2010.
  101. ^ a b Sea World Education Department (1993). Toothed Whales. San Diego: Sea World Education Department Publication.
  102. ^ Leung, Elaine S.; Vergara, Valeria; Barrett-Lennard, Lance G. (2010). "Allonursing in captive belugas (Delphinapterus leucas)". Zoo Biology. 29 (5): 633–7. doi:10.1002/zoo.20295. PMID 20127963.
  103. ^ Pappas, Stephanie (20 June 2019). "First-Ever Beluga-Narwhal Hybrid Found in the Arctic". Live Science. Archived from the original on 20 June 2019. Retrieved 20 June 2019.
  104. ^ Skovrind, M.l; Castruita, J. A. S.; Haile, J.; Treadaway, E. C.; Gopalakrishnan, S.; Westbury, M. V.; Heide-Jørgensen, M. P.; Szpak, P.; Lorenzen, E. D. (2019). "Hybridization between two high Arctic cetaceans confirmed by genomic analysis". Scientific Reports. 9 (1): 7729. Bibcode:2019NatSR...9.7729S. doi:10.1038/s41598-019-44038-0. PMC 6586676. PMID 31221994.
  105. ^ Au, W. W. L.; Carder, D. A.; Penner, R. H.; Scronce, B. L. (1985). "Demonstration of adaptation in beluga whale echolocation signals". The Journal of the Acoustical Society of America. 77 (2): 726–30. Bibcode:1985ASAJ...77..726A. doi:10.1121/1.392341. PMID 3973242.
  106. ^ "'Who told me to get out?': Beluga whale mimics human speech". The Sydney Morning Herald. 22 October 2012. Archived from the original on 2 September 2022. Retrieved 2 September 2022.
  107. ^ Ridgway, Sam; Carder, Donald; Jeffries, Michelle; Todd, Mark (23 October 2012). "Spontaneous human speech mimicry by a cetacean". Current Biology. 22 (20): R860–R861. Bibcode:2012CBio...22.R860R. doi:10.1016/j.cub.2012.08.044. PMID 23098588. S2CID 18176580.
  108. ^ "The Canaries of the Sea, granted a pardon, this time…". ePluribus Media. Archived from the original on 29 November 2009. Retrieved 7 August 2010.
  109. ^ Bonner, W (1989). Whales of the World. New York: Facts on File Journals. p. 191. ISBN 978-0-8160-5216-5.
  110. ^ Panova, E. M.; Belikov, R. A.; Agafonov, A. V.; Kirillova, O. I.; Chernetsky, A. D.; Belkovich, V. M. (2015). "Intraspecific variability in the "vowel"-like sounds of beluga whales (Delphinapterus leucas): Intra- and interpopulation comparisons". Marine Mammal Science. 32 (2): 452–465. doi:10.1111/mms.12266.
  111. ^ a b c Rice DW (1998). Wartzok D (ed.). Marine mammals of the world: systematics and distribution (4 ed.). Lawrence, KS. US: Society for Marine Mammalogy, Special Journal. p. 231. ISBN 978-1-891276-03-3.
  112. ^ "Beluga Whale". Fisheries and Oceans Canada. Archived from the original on 5 August 2017.
  113. ^ Artyukhin, Yu.B.; Burkanov, V.N. (1999). Sea birds and mammals of the Russian Far East: a Field Guide (in Russian). Moscow: АSТ Publishing. p. 215. ISBN 978-5237044751.
  114. ^ a b c Suydam RS, Lowry LF, Frost KJ, O' Corry-Crowe GM, Pikok D JR (2001). "Satellite Tracking of Eastern Chukchi Sea Beluga Whales into the Arctic Ocean". Arctic. 54 (3): 237–243. doi:10.14430/arctic784.
  115. ^ Andrei, Mihai (6 April 2018). "Beluga whales value culture and family ties". ZME Science. Archived from the original on 15 April 2018. Retrieved 14 April 2018.
  116. ^ Barber DG, Saczuk E, Richard PR (2001). "Examination of Beluga-Habitat Relationships through the Use of Telemetry and a Geographic Information System". Arctic. 54 (3): 305–316. doi:10.14430/arctic790.
  117. ^ "Whale Carcass in Alaska River Mystifies Experts". Los Angeles Times. 16 June 2006. Archived from the original on 11 January 2012. Retrieved 3 August 2010.
  118. ^ Gewalt W (1994). "Wale und Delphine 1 -Delphinapterus leucas – Weißwal oder Beluga". Handbuch der Säugetiere Europas. Meeressäuger. Teil IA (in German). Aula-Verlag, Wies-baden. pp. 185–208. ISBN 978-3-89104-560-2.
  119. ^ "Beluga's body in river baffles scientists". South Bend Tribune. Archived from the original on 13 December 2013. Retrieved 10 September 2012.
  120. ^ "Beluga Whale". Alaskan Naure. Archived from the original on 2 June 2013.
  121. ^ Hauser, Donna D. W.; Laidre, Kristin L.; Suydam, Robert S.; Richard, Pierre R. (24 April 2014). "Population-specific home ranges and migration timing of Pacific Arctic beluga whales (Delphinapterus leucas)". Polar Biology. 37 (8): 1171–1183. Bibcode:2014PoBio..37.1171H. doi:10.1007/s00300-014-1510-1. S2CID 7223010.
  122. ^ Heide Jørgensen MP & Reeves RR (1996). "Evidence of a decline in beluga, Delphinapterus leucas, abundance off West Greenland". ICES J Mar Sci. 53 (1): 61–72. Bibcode:1996ICJMS..53...61H. doi:10.1006/jmsc.1996.0006.
  123. ^ "beluga whale". Irish Whale and Dolphin Group. Archived from the original on 8 March 2016.
  124. ^ "Beluga whale sightings in SNH marine renewables report". BBC News. 21 February 2012. Archived from the original on 2 June 2014.
  125. ^ "Dolphin and whale watching in the Scotland". Wildlife Extra. Archived from the original on 2 June 2014.
  126. ^ "Beluga Whale". Hebridean Whale and Dolphin Trust. Archived from the original on 20 June 2013.
  127. ^ Sato, H.; Ichimura, M. (2011). "The Sighting Record of Beluga (White Whale) Delphinapterus leucas in Shiretoko–Nemuro Strait Water, Eastern Hokkaido, Japan. Sea Life Watch in Shibetsu". Bulletin of the Shiretoko Museum. 32: 45–52.
  128. ^ Uni, Y (2006). "Whales, Dolphins and Porpoises off Shiretoko" (PDF). Bulletin of the Shiretoko Museum. 27: 37–46. Archived (PDF) from the original on 14 July 2014.
  129. ^ "Volcano-bay Marine-animals Waching Association". Archived from the original on 23 September 2015. of Muroran Renaissance
  130. ^ Mukai. T. "KK-ELM". Archived from the original on 20 October 2015.
  131. ^ Sasamori K. "Muroran Dolphin and Whale Watching". Archived from the original on 14 July 2014.
  132. ^ Imai Y. "野生のシロイルカ/ベルーガ in 日本 Beluga, the White Whale observations in Japanese waters". YouTube. Archived from the original on 8 June 2015.
  133. ^ "흰고래 Delphinaterus leucas 영명 : Beluga, White whale 일명 : 시로이루카". whalelove.com. Archived from the original on 4 March 2016.
  134. ^ "ベルーガ(シロイルカ) Delphinapterus leucas" (PDF). Association for Protection of Marine Communities. 1 January 2015. Archived from the original (PDF) on 20 November 2015.
  135. ^ Nakayama Y. (2016). "北極のベルーガ、北海道でひとりぼっち 遊び相手は漁師". The Asahi Shimbun. Archived from the original on 25 March 2017.
  136. ^ a b c d e Reyes JC (1991). The conservation of small cetaceans: a review. Report prepared for the Secretariat of the Convention on the Conservation of Migratory Species of Wild Animals. UNEP/CMS Secretariat, Bonn.
  137. ^ Hobbs RC, Laidre KL, Vos DJ, Mahoney BA, Eagleton M (2005). "Movements and Area Use of Belugas, Delphinapterus leucas, in a Subarctic Alaskan Estuary" (PDF). Arctic. 58 (4): 331–340. doi:10.14430/arctic447. Archived (PDF) from the original on 10 February 2012.
  138. ^ Rugh DJ, Mahoney BA, Smith BK (2004). "Aerial Surveys of Beluga Whales in Cook Inlet, Alaska, Between June 2001 and June 2002". NOAA Technical Memorandum NMFS AFSC. no. 145. p. 20. Archived from the original on 12 May 2019. Retrieved 7 August 2010.
  139. ^ "Research Document 2012/074". Dfo-mpo.gc.ca. Archived from the original on 24 October 2016. Retrieved 23 November 2021.
  140. ^ Goetz, Kimberly T.; Rugh, David J.; Read, Andrew J. & Hobbs, Roderick C. (2 October 2018). "Habitat use in a marine ecosystem: beluga whales Delphinapterus leucas in Cook Inlet, Alaska" (PDF). National Marine Mammal Laboratory, Alaska Fisheries Science Center, NMFS, NOAA, Washington, USA. Archived (PDF) from the original on 15 June 2010.
  141. ^ Loseto, L.L.; Richard, P.; Stern, G.A.; Orr, J.; Ferguson, S.H. (1 December 2006). "Segregation of Beaufort Sea beluga whales during the open-water season". Canadian Journal of Zoology. 84 (12): 1743–1751(9). doi:10.1139/Z06-160.
  142. ^ a b c "Report of the NAMMCO Global Review of Monodontids" (PDF). Hillerød, Denmark: NAMMCO. 13–16 March 2017. Archived (PDF) from the original on 24 March 2023. Retrieved 20 February 2023.
  143. ^ a b c d e Ellis, Richard (1991). Men and Whales (1st ed.). The Lyons Press. p. 560. ISBN 978-1-55821-696-9. Archived from the original on 14 May 2021. Retrieved 12 July 2018.
  144. ^ a b c d Hoover C, Bailey M, Higdon J, Ferguson SH, Sumalia R (March 2013). "Estimating the Economic Value of Narwhal and Beluga Hunts in Hudson Bay, Nunavut". Arctic. 66: 1–16. doi:10.14430/arctic4261. S2CID 59126947.
  145. ^ Heide-Jørgensen, Mads Peter (January 1994). "Distribution, exploitation and population status of white whales (Delphinapterus leucas) and narwhals (Monodon monoceros) in West Greenland". Meddelelser om Grønland, Bioscience. 39: 135–149. doi:10.7146/mogbiosci.v39.142541.
  146. ^ a b c d Bettridge, Shannon, Robert L. Brownell Jr., Melissa Andersen Garcia, Rod C. Hobbs, Cheri L. McCarty, Richard D. Methot Jr., Debra L. Palka, Patricia E. Rosel, Kathryn S. Swails, and Barbara L. Taylor (1 March 2016). "Status Review of the Sakhalin Bay-Amur River Beluga Whale (Delphinapterus leucas) under the Marine Mammal Protection Act" (PDF). cites Shpak, Meschersky, Hobbs, Andrews, Glazov, Chelintsev, Kuznetsova, Solovyev, Nazarenko, Michaud, and Mukhametov. 2011. Current status of the Sakhalin-Amur beluga aggregation (The Okhotsk Sea, Russia): sustainability assessment. Report for 2007–2010 stages: Report presented at IUCN Independent Scientific Review Panel, Chicago, 6–7 March 2011 (unpublished). 68p and 5 Appendices. Archived (PDF) from the original on 30 April 2017. Retrieved 7 April 2018.{{cite web}}: CS1 maint: multiple names: authors list (link) This table uses their "high" estimate, since they say, page 23: "The high take scenario is considered the better of the two because it accounts for times when takes are known to have occurred but are not documented. Additionally, we did not account for beluga whales that are struck and lost because these data are not available, so the high take option may even be an underestimate."
  147. ^ a b Master, Farah (20 September 2018). "Tidal wave of Chinese marine parks fuels murky cetacean trade". Reuters. Archived from the original on 18 November 2018. Retrieved 17 November 2018.
  148. ^ Kustikova, Alisa (8 November 2018). "It's like a detention center!, "Это как СИЗО!"". Новая газета – Novayagazeta.ru (in Russian). Archived from the original on 24 November 2018. Retrieved 23 November 2018.
  149. ^ "In Primorye, the court arrested killer whales and belugas in the case of the illegal export of mammals abroad, В Приморье суд арестовал косаток и белух по делу о незаконном вывозе млекопитающих за границу". Новая газета – Novayagazeta.ru (in Russian). 23 November 2018. Archived from the original on 23 November 2018. Retrieved 23 November 2018.
  150. ^ Tyrrell, Martina (2007). "Sentient Beings and Wildlife Resources: Inuit, Beluga Whales and Management Regimes in the Canadian Arctic". Human Ecology. 35 (5): 575–86. Bibcode:2007HumEc..35..575T. doi:10.1007/s10745-006-9105-2. S2CID 153470505.
  151. ^ Citta, John J.; Suydam, Robert S.; Quakenbush, Lori T.; Frost, Kathryn J.; O'Corry-Crowe, Gregory M. (22 November 2013). "Dive Behavior of Eastern Chukchi Beluga Whales (Delphinapterus leucas), 1998–2008". Arctic. 66 (4). doi:10.14430/arctic4326.
  152. ^ a b c d Boltunov, Andrei N.; Belikov, Stanislav E. (2002). "Belugas (Delphinapterus leucas) of the Barents, Kara and Laptev seas". NAMMCO Sci. Publ. 4: 149–168. doi:10.7557/3.2842 – via Septentrio Academic Publishing, Arctic University of Norway.
  153. ^ a b c d Burns, John J. and Glenn A. Seaman (1 November 1986). "Investigations of Belukha Whales in Coastal Waters of Western and Northern Alaska II. Biology and Ecology" (PDF). Outer Continental Shelf Environmental Assessment Program. Alaska Department of Fish and Game. Archived (PDF) from the original on 27 March 2018.
  154. ^ Madison, J. (2014). All About Marine Animals - Animals of the Seas and Oceans.
  155. ^ a b c Dionne, Suzan & Gourbilière, Claire (2007). "St. Lawrence Beluga". Encyclopedia of French Cultural Heritage in North America. Archived from the original on 4 March 2013. Retrieved 1 September 2010.
  156. ^ a b c d e f "Beluga Whales in Captivity" (PDF). Special Report on Captivity 2006. Canadian Marine Environment Protection Society. 2006. Archived from the original (PDF) on 26 December 2014. Retrieved 26 December 2014.
  157. ^ Reeves, R. R. & Mitchell, E. (1984). "Catch history and initial population of white whales (Delphinapterus leucas) in the river and gulf of St. Lawrence, eastern Canada". Canadian Field-Naturalist (111): 63–121. Archived from the original on 5 November 2012. Retrieved 7 September 2010.
  158. ^ Harwood, Lois A., Pamela Norton, Billy Day and Patricia A. Hall (1 March 2002). "The Harvest of Beluga Whales in Canada's Western Arctic: Hunter-Based Monitoring of the Size and Composition of the Catch (has data through 1984)". Arctic. 55: 10–20. doi:10.14430/arctic687. Archived from the original on 3 May 2018.{{cite journal}}: CS1 maint: multiple names: authors list (link) Includes struck and lost.
  159. ^ Fisheries Joint Management Committee (2013). "Beaufort Sea Beluga Management Plan, 4th amended printing" (PDF). Archived (PDF) from the original on 25 March 2018. Retrieved 7 April 2018. Includes struck and lost.
  160. ^ "Marine Mammal Stock Assessment Reports (SARs) by Region". U.S. National Oceanic and Atmospheric Administration. 17 September 2018. Archived from the original on 3 May 2018. Retrieved 7 April 2018. includes struck and lost.
  161. ^ Loseto, Lisa L.; Brewster, Jasmine D.; Ostertag, Sonja K.; Snow, Kathleen; MacPhee, Shannon A.; McNicholl, Darcy G.; Choy, Emily S.; Giraldo, Carolina; Hornby, Claire A. (21 February 2018). "Diet and feeding observations from an unusual beluga harvest in 2014 near Ulukhaktok, Northwest Territories, Canada". Arctic Science. 4 (3): 421–431. doi:10.1139/as-2017-0046. hdl:1807/88141. Archived from the original on 24 January 2019. Retrieved 24 January 2019.
  162. ^ Suluk, Thomas K. and Blakney, Sherrie L. (2008). "Land Claims and Resistance to the Management of Harvester Activities in Nunavut" (PDF). Arctic. 61 (5): 62–70. doi:10.14430/arctic102. hdl:10535/5552. Archived (PDF) from the original on 21 September 2017 – via University of Calgary.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  163. ^ Kishigami, Noboru (2005). "Co-Management of Beluga Whales in Nunavik (Arctic Quebec), Canada". Senri Ethnological Studies. 67: 121–144. Archived from the original on 3 May 2018.
  164. ^ Rogers, Sarah (22 August 2016). "Nunatsiaq News 2016-08-22: NEWS: Nunavik's beluga season closes early". Nunatsiaq News. Archived from the original on 12 July 2018. Retrieved 7 April 2018.
  165. ^ Heide-Jorgensen, M.P. and E. Garde (1 March 2017). Catch statistics for belugas in Greenland 1862 to 2016 – via NAMMCO/JCNB Joint Working Group on narwhals and belugas, Copenhagen. Paper is not online. This table uses their "high" estimate (which includes struck and lost), without harvests from ice entrapments (which would die even if not harvested).
  166. ^ Stanek, Ronald (1 July 1994). "The Subsistence Use of Beluga Whale in Cook Inlet by Alaska Natives, 1993" (PDF). Alaska Dept of Fish and Game. Archived (PDF) from the original on 9 August 2017. Retrieved 7 April 2018.
  167. ^ "Participation in subsistence fishing by residents-Beluga harvested by residents (downloadable data)". 2011. Archived from the original on 27 March 2018. Retrieved 7 April 2018.
  168. ^ Muto, M.M., V. T. Helker, R. P. Angliss, B. A. Allen, P. L. Boveng, J.M. Breiwick, M. F. Cameron, P. J. Clapham, S. P. Dahle, M. E. Dahlheim, B. S. Fadely, M.C. Ferguson, L. W. Fritz, R. C. Hobbs, Y. V. Ivashchenko, A. S. Kennedy, J.M. London, S. A. Mizroch, R. R. Ream, E. L. Richmond, K. E. W. Shelden, R. G. Towell, P. R. Wade, J. M. Waite, and A. N. Zerbini (2017). "Alaska Marine Mammal Stock Assessments, 2017 (draft)". Marine Mammal Laboratory, Alaska Fisheries Science Center, NMFS, NOAA. Retrieved 8 April 2018.{{cite web}}: CS1 maint: multiple names: authors list (link)
  169. ^ "Draft Marine Mammal Stock Assessment Reports, NOAA Fisheries". U.S. National Oceanic and Atmospheric Administration. 31 January 2018. Archived from the original on 28 April 2018. Retrieved 8 April 2018.
  170. ^ Hernández, Clara (17 November 2006). "Un grupo de cazadores matará en Canadá a cerca de 80 belugas que han quedado atrapadas por el hielo" (in Spanish). 20 minutos.es – Internacional. Archived from the original on 17 October 2019. Retrieved 12 September 2012.
  171. ^ Freeman, Milton M. R. "Polar Bear Predation on Beluga in the Canadian Arctic" (PDF). McMaster University, Hamilton, Ontario. Archived (PDF) from the original on 15 April 2010. Retrieved 12 August 2010.
  172. ^ a b Shelden KE, Rugh DJ, Mahoney BA, Dahlheim ME (2003). "Killer whale predation on belugas in Cook Inlet, Alaska: Implications for a depleted population" (PDF). Mar. Mammal Sci. 19 (3): 529–544. Bibcode:2003MMamS..19..529S. doi:10.1111/j.1748-7692.2003.tb01319.x. S2CID 14936486. Archived (PDF) from the original on 24 December 2012.
  173. ^ Lowry LF, Nelson RR, Frost KJ (1987). "Observations of killer whales, Orcinus orca, in western Alaska: Sightings, strandings, and predation on other marine mammals". Ont. Field-Nat. 101 (1): 6–12. doi:10.5962/p.355848.
  174. ^ a b Beland, Pierre (1996). Beluga: A Farewell to Whales (1 ed.). The Lyons Press. p. 224. ISBN 978-1-55821-398-2.
  175. ^ "Marine Pollution: Causes and Effects". Bamfield Marine Sciences Centre Public Education Program. Archived from the original on 18 February 2013.
  176. ^ Metcalfe, C; Metcalfe, T; Ray, S; Paterson, G; Koenig, B (1999). "Polychlorinated biphenyls and organochlorine compounds in brain, liver and muscle of beluga whales (Delphinapterus leucas) from the Arctic and St. Lawrence estuary". Marine Environmental Research. 47 (1): 1–15. Bibcode:1999MarER..47....1M. doi:10.1016/S0141-1136(98)00107-X.
  177. ^ a b Smith, T. G.; D. J. St. Aubin & J. R. Geraci (1990). Advances in Research on the Beluga Whale, Delphinapterus leucas. Ottawa: Department of Fisheries and Oceans. ISBN 978-0-660-13817-6. OL 7626804M.
  178. ^ Hansen, Carstenthye; Nielsen, Christianovergaard; Dietz, Rune; Hansen, Martinmunk (1990). "Zinc, cadmium, mercury and selenium in minke whales, belugas and narwhals from West Greenland". Polar Biology. 10 (7): 529–39. Bibcode:1990PoBio..10..529H. doi:10.1007/BF00233702. S2CID 10222948.
  179. ^ Loseto, L.L.; Stern, G.A.; Macdonald, R.W. (2015). "Distant drivers or local signals: Where do mercury trends in western Arctic belugas originate?". Science of the Total Environment. 509–510: 226–236. Bibcode:2015ScTEn.509..226L. doi:10.1016/j.scitotenv.2014.10.110. PMID 25442642.
  180. ^ a b c Martineau, D.; Lemberger, K.; Dallaire, A.; Labelle, P.; Lipscomb, T. P.; Michel, P.; Mikaelian, I. (2002). "Cancer in Wildlife, a Case Study: Beluga from the St. Lawrence Estuary, Québec, Canada". Environmental Health Perspectives. 110 (3): 285–92. doi:10.1289/ehp.02110285. PMC 1240769. PMID 11882480.
  181. ^ Guise, S. D.; Lagace, A.; Beland, P. (1994). "Tumors in St. Lawrence Beluga Whales (Delphinapterus leucas)". Veterinary Pathology. 31 (4): 444–9. doi:10.1177/030098589403100406. PMID 7941233.
  182. ^ Caron LM, Sergeant DE (1988). "Yearly variation in the frequency of passage of beluga whales (Delphinapterus leucas) at the mouth of the Saguenay River, Quebec, over the past decade". Nat Can. 115 (2): 111–116.
  183. ^ Lesage, Veronique; Barrette, Cyrille; Kingsley, Michael C. S.; Sjare, Becky (January 1999). "The Effect of Vessel Noise on the Vocal Behavior of Belugas in the St. Lawrence River Estuary, Canada" (PDF). Marine Mammal Science. 15 (1): 65–84. Bibcode:1999MMamS..15...65L. doi:10.1111/j.1748-7692.1999.tb00782.x. Archived (PDF) from the original on 2 February 2012.
  184. ^ Finley KJ, Miller GW, Davis RA, Greene CR (1990). "Reactions of belugas, Delphinapterus leucas, and narwhals, Monodon monoceros, to ice-breaking ships in the Canadian High Arctic. In "Advances in research on the beluga whale, Delphinapterus leucas"". Can Bull Fish Aquat Sci. 224: 97–117. Archived from the original on 5 November 2012.
  185. ^ Sea World.org (2002). "Beluga Whales – Longevity and Causes of Death". Archived from the original on 19 June 2010. Retrieved 30 July 2010.
  186. ^ a b c Dierauf, L. & Gulland, F. (2001). CRC Handbook of Marine Mammal Medicine: Health, Disease, and Rehabilitation. CRC Press. pp. 26, 303, 359. ISBN 978-0-8493-0839-0.
  187. ^ Calle, Paul P.; Kenny, David E.; Cook, Robert A. (1993). "Successful treatment of suspected erysipelas septicemia in a beluga whale (Delphinapterus leucas)". Zoo Biology. 12 (5): 483–90. doi:10.1002/zoo.1430120510.
  188. ^ Wazura, K. W.; Strong, J. T.; Glenn, C. L.; Bush, Albert O. (1986). "Helminths of the Beluga Whale (Delphinapterus leucas) from the Mackenzie River Delta, Northwest Territories". Journal of Wildlife Diseases. 22 (3): 440–2. doi:10.7589/0090-3558-22.3.440. PMID 3735598. S2CID 12088478.
  189. ^ "The Whales, New York Tribune, August 9, 1861". New York Tribune. 9 August 1861. Archived from the original on 7 June 2003. Retrieved 5 December 2011.
  190. ^ Held, Amy (11 June 2019). "Canada Bans Keeping Whales And Dolphins In Captivity". npr. Archived from the original on 5 May 2023. Retrieved 30 September 2019.
  191. ^ a b "Beluga Whales". Mystic Aquarium. Archived from the original on 13 October 2013. Retrieved 21 November 2014.
  192. ^ "Species of the Month, Juno". Mystic Aquarium. Archived from the original on 19 January 2013. Retrieved 21 November 2014.
  193. ^ "Beluga Whales Training". GeorgiaAquarium. 4 March 2008. Archived from the original on 16 March 2016. Retrieved 21 November 2014.
  194. ^ "Mariachi Band Serenades Beluga Whale". HuffPost. 3 August 2011. Archived from the original on 29 November 2014. Retrieved 21 November 2014.
  195. ^ a b "The Story of Navy Dolphins". PBS. Archived from the original on 30 December 2008. Retrieved 12 October 2008.
  196. ^ "Reddet russisk "militærhval" på norgesbesøk". Dagbladet (in Norwegian). 27 April 2019. Archived from the original on 29 April 2019. Retrieved 29 April 2019.
  197. ^ Henley, Jon (2 May 2019). "As experts fear for its survival, Tufjord residents told not to feed beluga so that it can learn to forage". The Guardian. Archived from the original on 3 May 2019. Retrieved 3 May 2019.
  198. ^ "Merlin Entertainments plc - 2018 Interim Results – Company Announcement - FT.com". Financial Times. 2 August 2018. Archived from the original on 21 November 2018. Retrieved 21 November 2018.
  199. ^ a b Ástvaldsson, Jóhann Páll (28 June 2018). "Beluga Whales Train for Sanctuary in Iceland". Iceland Review. Archived from the original on 21 November 2018. Retrieved 21 November 2018.
  200. ^ Wong, Li Za (10 July 2018). "World's First Open Water Sanctuary For Beluga Whales To Open Spring 2019 In Iceland". Star2.com. Archived from the original on 22 November 2018. Retrieved 21 November 2018.
  201. ^ Mountain, Michael (15 June 2017). "Merlin Entertainment Seeks to Move Belugas to Sanctuary". The Whale Sanctuary Project. Archived from the original on 21 November 2018. Retrieved 21 November 2018.
  202. ^ "Les parcs à thème controversés SeaWorld arrivent bientôt en Asie". Sciences et Avenir (in French). 27 March 2017. Archived from the original on 13 August 2020. Retrieved 23 November 2018.
  203. ^ a b "Belugas "floated away" to China. Белухи "уплыли" в Китай. За что задержан директор ФГБНУ "ТИНРО-Центр" Лев Бочаров?". Porto Franko, Vladivostok. Archived from the original on 24 November 2018. Retrieved 23 November 2018. Article says belugas cost USD 70,000 or 60,000, while orcas cost USD 7 million, while another article says orcas cost USD 1 million (RUB 67 million)
  204. ^ "Косатка на миллион". Novayagazeta.ru. 14 September 2018. Archived from the original on 23 November 2021. Retrieved 23 November 2021.
  205. ^ "Ceta Base – Captive Cetacean Database – Cetacean Inventory • U.S. & Canada". cetabase.org. 31 January 2018. Archived from the original on 22 November 2018. Retrieved 22 November 2018.
  206. ^ "Arrests made in Russia following illegal whale trafficking scandal". WDC, Whale and Dolphin Conservation. 21 March 2017. Archived from the original on 18 April 2024. Retrieved 23 November 2018.
  207. ^ "Beluga (Delphinapterus leucas)Facts – Distribution – In the Zoo". WAZA : World Association of Zoos and Aquariums. Archived from the original on 10 February 2012. Retrieved 5 December 2011.
  208. ^ "Nanuq". Cetacousin. Retrieved 9 September 2012.[permanent dead link]
  209. ^ "Beluga Whale Calf Born at Shedd Aquarium". Association of Zoos and Aquariums. Archived from the original on 14 September 2012. Retrieved 9 September 2012.
  210. ^ "Male Beluga Whale Arrives at Mystic Aquarium". Mystic Aquarium. Archived from the original on 20 January 2012. Retrieved 9 September 2012.
  211. ^ Pedicini, Sandra. "SeaWorld switches beluga whales". OrlandoSentinel.com. Archived from the original on 22 November 2018. Retrieved 22 November 2018.
  212. ^ Inmaculada Sanz (3 November 2006). "Nace la primera cría de ballena beluga en cautividad en Europa" (in Spanish). Noticias 20minutos. Archived from the original on 7 February 2011.
  213. ^ "Muere la ballena beluga que nació hace 25 días en el Oceanográfico de Valencia" (in Spanish). 27 November 2006. Archived from the original on 1 July 2013.
  214. ^ eldiario.es (16 November 2016). "Kylu, la beluga que nació en el Oceanogràfic de Valencia un día de superluna" (in Spanish). Archived from the original on 17 January 2017.
  215. ^ Lepisto, Christine (2 August 2009). "Beluga Whale Saves Diver". Archived from the original on 30 March 2010. Retrieved 31 August 2010.
  216. ^ "Wal Rettet Ertrinkende Taucherin!". Archived from the original on 2 August 2009. Retrieved 27 September 2009.
  217. ^ "Born to Be Free". IMDb. 18 July 2017. Archived from the original on 14 April 2017. Retrieved 12 October 2017.
  218. ^ "Sonic Sea – Wild & Scenic Film Festival". Wild & Scenic Film Festival. Archived from the original on 12 October 2017. Retrieved 12 October 2017.
  219. ^ Proctor, Jason. "Vancouver Aquarium sues filmmaker over critical documentary". CBC News. Archived from the original on 24 March 2017. Retrieved 12 October 2017.
  220. ^ "5 things you didn't know about Churchill". frontiersnorth.com. 4 February 2015. Archived from the original on 5 August 2020. Retrieved 22 January 2020.
  221. ^ a b UCLA Department of Chemistry and Biochemistry. "Beluga Whale Watching". Archived from the original on 26 May 2010. Retrieved 11 February 2010.
  222. ^ Blane, JM.; Jackson, R (1994). "The impact of ecotourism boats on the St. Lawrence beluga whales". Environmental Conservation. 21 (3): 267–269. Bibcode:1994EnvCo..21..267B. doi:10.1017/S0376892900033282. S2CID 85821363. Archived from the original on 5 November 2012.
  223. ^ National Oceanic and Atmospheric Administration (January 2004). "Marine Wildlife Viewing Guidelines" (PDF). Archived (PDF) from the original on 17 June 2010. Retrieved 6 August 2010.
  224. ^ Shpatak A. (2012). "Japan Sea. Rudnaya Bay. Polar White Whale". The 35PHOTO.ru. Archived from the original on 19 January 2015. Retrieved 19 January 2015.
  225. ^ Berg Olsen, Martine (26 September 2018). "Benny the beluga whale spotted swimming in River Thames again". Metro. Archived from the original on 26 September 2018. Retrieved 26 September 2018.
  226. ^ "Beluga whale has finally left the Thames, say experts". The Telegraph. The Daily Telegraph. 13 May 2019. Archived from the original on 11 January 2022. Retrieved 7 May 2020.
  227. ^ "Beluga whales sighted in at least 2 P.E.I. locations". Cbc.ca. Archived from the original on 14 May 2021. Retrieved 23 November 2021.
  228. ^ "Police disperse crowds gathered to catch glimpse of beluga". Cbc.ca. Archived from the original on 18 April 2024. Retrieved 23 November 2021.
  229. ^ "Activists locate 'extremely thin' Beluga whale in Seine - la Prensa Latina Media". 5 August 2022. Archived from the original on 6 August 2022. Retrieved 6 August 2022.
  230. ^ "Study: Male beluga whale mimics human speech". 23 October 2012. Archived from the original on 14 July 2014.
  231. ^ "The Story of One Whale Who Tried to Bridge the Linguistic Divide Between Animals and Humans". Smithsonian Magazine. June 2014. Archived from the original on 4 July 2014. Retrieved 13 July 2014.
  232. ^ Jefferson TA, Karkzmarski L, Laidre K, O'Corry-Crowe G, Reeves R, Rojas-Bracho L, Secchi E, Slooten E, Smith BD, Wang JY, Zhou K (2012). "Delphinapterus leucas". IUCN Red List of Threatened Species. 2012: e.T6335A17690692. doi:10.2305/IUCN.UK.2012.RLTS.T6335A17690692.en.
  233. ^ Lloyd Lowry (University of Alaska Fairbanks, School of Fisheries and Ocean Sciences); University), Greg O'Corry-Crowe (Florida Atlantic; Hobbs, Roderick (4 August 2018). "IUCN Red List of Threatened Species: Beluga". IUCN Red List of Threatened Species. doi:10.2305/iucn.uk.2019-1.rlts.t61442a50384653.en. S2CID 240347088. Archived from the original on 4 March 2020. Retrieved 15 March 2020.
  234. ^ Rosen, Yereth (17 October 2008). "Beluga whales in Alaska listed as endangered". Reuters. Archived from the original on 20 October 2008. Retrieved 17 October 2008.
  235. ^ "Endangered and Threatened Species; Endangered Status for the Cook Inlet Beluga Whale" (PDF). National Oceanic and Atmospheric Administration. 22 October 2008. Archived (PDF) from the original on 12 May 2009. Retrieved 26 August 2009.
  236. ^ Herbert, H. Josef (17 October 2008). "Government declares beluga whale endangered". Associated Press. Archived from the original on 28 October 2008. Retrieved 17 October 2008.
  237. ^ a b "NOAA Releases New Abundance Estimate for Endangered Cook Inlet Beluga Whales". NOAA Fisheries. 3 February 2020. Archived from the original on 20 February 2020. Retrieved 15 March 2020.
  238. ^ a b "Beluga Whale". NOAA. NOAA Fisheries. 2 March 2020. Archived from the original on 31 March 2020. Retrieved 15 March 2020.
  239. ^ a b c Laidre, K. L.; Stirling, I.; Lowry, L.; Wiig, Ø; Heide-Jørgensen, M. P.; Ferguson, S. (2008). "Quantifying the sensitivity of arctic marine mammals to climate-induced habitat change". Ecological Applications. 18 (2): S97–S125. Bibcode:2008EcoAp..18S..97L. doi:10.1890/06-0546.1. PMID 18494365. S2CID 23765771.
  240. ^ Hauser, Donna D. W.; Laidre, Kristin L.; Stafford, Kathleen M.; Stern, Harry L.; Suydam, Robert S.; Richard, Pierre R. (2017). "Decadal shifts in autumn migration timing by Pacific Arctic beluga whales are related to delayed annual sea ice formation". Global Change Biology. 23 (6): 2206–2217. Bibcode:2017GCBio..23.2206H. doi:10.1111/gcb.13564. PMID 28001336. S2CID 44002260.
  241. ^ a b c d e Liao, Bill (2009). "Beluga Whales and Climate Change" (PDF). IUCN Red List. Archived from the original (PDF) on 14 May 2021. Retrieved 15 March 2020.
  242. ^ O'Corry-Crowe, Greg; Mahoney, Andrew R.; Suydam, Robert; Quakenbush, Lori; Whiting, Alex; Lowry, Lloyd; Harwood, Lois (30 November 2016). "Genetic profiling links changing sea-ice to shifting beluga whale migration patterns". Biology Letters. 12 (11): 20160404. doi:10.1098/rsbl.2016.0404. PMC 5134032.
  243. ^ a b National Oceanic and Atmospheric Administration (January 2004). "MMPA – The Marine Mammal Protection Act of 1972 as Amended (2007)" (PDF). Archived (PDF) from the original on 1 June 2010. Retrieved 6 August 2010.
  244. ^ a b "Appendix II of the Convention on the Conservation of Migratory Species of Wild Animals (CMS). As amended by the Conference of the Parties in 1985, 1988, 1991, 1994, 1997, 1999, 2002, 2005 and 2008. Effective: 5 March 2009" (PDF). Archived from the original (PDF) on 11 June 2011.
  245. ^ "Official CITES website". Convention on International Trade in Endangered Species of Wild Fauna and Flora. Archived from the original on 9 December 2009. Retrieved 20 December 2009.
  246. ^ Shih, Xenia. "In-depth: Belugas – Beluga Whales Under Threat". Jean-Michael Cousteau – Ocean Adventures. Archived from the original on 20 June 2017.
  247. ^ St. Lawrence Action Plan – Official Page. "St. Lawrence Action Plan For a Sustainable Development". Archived from the original on 25 January 2011. Retrieved 6 August 2010.
  248. ^ "Beluga Whale (St. Lawrence Estuary population)". Government of Canada. Archived from the original on 21 August 2017. Retrieved 22 August 2017.
  249. ^ a b c O'Brien, J. K.; Robeck, T. R. (28 April 2010). "Preservation of beluga (Delphinapterus leucas) spermatozoa using a trehalose-based cryodiluent and directional freezing technology". Reproduction, Fertility and Development. 22 (4): 653–663. doi:10.1071/RD09176. PMID 20353725.
  250. ^ O'Brien, J. K.; Robeck, T. R. (2010). "The Value of ex situ Cetacean Populations in Understanding Reproductive Physiology and Developing Assisted Reproductive Technology for ex situ and in situ Species Management and Conservation Efforts". International Journal of Comparative Psychology. 23 (3). doi:10.46867/IJCP.2010.23.03.11.
  251. ^ a b c Katsumata, Etsuko; Furuta, Chie; Katsumata, Hiroshi; Watanabe, Gen; Taya, Kazuyoshi (2006). "Basal Body Temperature Method for Detecting Ovarian Cycle in the Captive Beluga (Delphinapterus leucas)". Journal of Reproduction and Development. 52 (1): 59–63. doi:10.1262/jrd.17066. PMID 16276040. Archived from the original on 29 April 2021. Retrieved 15 March 2020.
  252. ^ Steinman, K. J.; O'Brien, J. K.; Monfort, S. L.; Robeck, T. R. (1 February 2012). "Characterization of the estrous cycle in female beluga (Delphinapterus leucas) using urinary endocrine monitoring and transabdominal ultrasound: Evidence of facultative induced ovulation". General and Comparative Endocrinology. 175 (3): 389–397. doi:10.1016/j.ygcen.2011.11.008. PMID 22134179.
  253. ^ Richard, Justin T.; Schmitt, Todd; Haulena, Martin; Vezzi, Noël; Dunn, J. Lawrence; Romano, Tracy A.; Sartini, Becky L. (29 May 2017). "Seasonal variation in testes size and density detected in belugas (Delphinapterus leucas) using ultrasonography". Journal of Mammalogy. 98 (3): 874–884. doi:10.1093/jmammal/gyx032.
  254. ^ Robeck, T. R.; Steinman, K. J.; Montano, G. A.; Katsumata, E.; Osborn, S.; Dalton, L.; Dunn, J. L.; Schmitt, T.; Reidarson, T.; O'Brien, J. K. (1 October 2010). "Deep intra-uterine artificial inseminations using cryopreserved spermatozoa in beluga (Delphinapterus leucas)". Theriogenology. 74 (6): 989–1001. doi:10.1016/j.theriogenology.2010.04.028. PMID 20570326.
  255. ^ O'Brien, J. K.; Steinman, K. J.; Schmitt, T.; Robeck, T. R. (6 October 2008). "Semen collection, characterisation and artificial insemination in the beluga (Delphinapterus leucas) using liquid-stored spermatozoa". Reproduction, Fertility and Development. 20 (7): 770–783. doi:10.1071/RD08031. PMID 18842179.
  256. ^ The Internet Movie Database (4 August 1963). "Pour la suite du monde". IMDb. Archived from the original on 4 January 2010. Retrieved 7 August 2010.
  257. ^ "Baby beluga". National Institutes of Health. Archived from the original on 27 May 2010. Retrieved 12 February 2010.
  258. ^ "Airbus beluga service". airbus.com. Archived from the original on 23 December 2010.
  259. ^ O'Hare, Maureen (18 February 2019). "Beluga XL spreads its wings at long last". CNN. Archived from the original on 7 December 2019. Retrieved 7 December 2019.
  260. ^ McCarthy, Kelly (17 June 2016). "Ty Burrell Makes a Splash as a Whale in 'Finding Dory'". ABC News. Archived from the original on 23 September 2020. Retrieved 7 December 2019.
  261. ^ Schillaci, Sophie (9 August 2013). "D23: Disney Sets Voice Casts for 'Finding Dory,' 'Inside Out' and 'Good Dinosaur'". The Hollywood Reporter. Archived from the original on 5 March 2016. Retrieved 9 August 2013.

Further reading