The beluga whale (Delphinapterus leucas) is a medium-sized cetacean belonging to the group known as odontocetes (toothed whales), which also includes sperm whales, killer whales, dolphins, and porpoises. Its closest relative is the narwhal. The common name is derived, in part, from the Russian word for white. They are also called “white whales;” however, this is somewhat of a misnomer, since only older animals are actually white. Common names used by Alaska Eskimos include Puugzaq (Siberian Yupik), Cetuaq (Central Yupik), and Sisuaq (Inupiat). Belugas range widely in arctic and subarctic waters and are often the most important small cetacean to northern coastal peoples.
General description: At birth beluga whales are dark blue-gray in color. They measure approximately 5 feet (1.5 m) long and weigh 90 to 130 pounds (40-60 kg). The color gradually lightens, and they are usually white by age 5 or 6. Adult males are from 11 to 15 feet (3.4-4.6 m) long and weigh 1,000 to 2,000 pounds (450-900 kg). Adult females are smaller, seldom exceeding 12 feet (3.7 m) in length. The size to which belugas grow varies in different parts of the range. Individuals more than 20 feet (6.1 m) long have occasionally been recorded, though not in Alaska.
Belugas are somewhat more robust-bodied than other porpoises and dolphins due to the presence of a blubber layer, which can be as much as 5 inches (12 cm) thick. The dorsal fin, characteristic of most whales, is reduced to a low ridge along the midline of the back. The head, which is characterized by a small “beak” and large bulging “melon,” is quite mobile in comparison to other whales. In fact, the beluga is the only whale that can bend its neck. These features appear to be adaptations to maneuvering and catching prey in muddy or ice-covered areas.
Simple, peg-like teeth first appear in the lower jaw. Teeth gradually appear in the upper jaw, and by adulthood there is a total of 40 teeth. Extensive wear and breakage of teeth occur throughout life.
Life history: Beluga calves are born in May-July, usually when the herds are near or in summer concentration areas. The single calf usually emerges tail first, and after birth it is guided to the surface and closely attended by its mother. Females become sexually mature at 4 to 5 years old, and males mature slightly later. Breeding occurs in March or April, and the total gestation period is about 14.5 months. Most adult females will produce one calf every three years. A calf is nursed by its mother for about two years. Belugas can probably live to be 40 years old.
Belugas shed their skin, or molt, each summer in about July. They concentrate in shallow water, often where there is coarse gravel, and rub on the bottom to help remove the old yellow skin. The skin grows about 100 times faster than normal during the molting period.
Natural enemies of belugas are polar bears and killer whales. Entanglement in gillnets can be a substantial cause of mortality in some areas.
Food habits: Winter foods of belugas are virtually unknown. In summer they feed on a variety of schooling and anadromous fishes that are sequentially abundant in coastal zones. Principal species eaten include herring, capelin, smelt, arctic and saffron cods, salmon, flatfishes, and sculpins. Octopus, squid, shrimps, crabs, and clams are eaten occasionally. Most feeding is done over the continental shelf and in nearshore estuaries and river mouths. In the shallow waters of Alaska, most feeding dives are probably to depths of 20 to 100 feet (6-30 m) and last two to five minutes. Satellite tagged belugas in Canada were found to dive to depths of 2,000 feet (600 m).
Distribution and movements: Belugas occur throughout arctic and subarctic waters of North America, Greenland, Europe, and Asia. They are often found in ice-covered regions in winter and spring and in coastal waters in summer and autumn. Two populations occur in Alaska. The Cook Inlet population occurs in the inlet and Shelikof Strait region, although wanderers have been seen east to Yakutat Bay and to Kodiak Island. Belugas of the Bering Sea population range throughout the Bering, Chukchi, and Beaufort seas. They winter in the drifting ice of the Bering Sea, moving in summer to concentration areas scattered along the coast from Bristol Bay to the Mackenzie River Delta in Canada. In Alaska, major concentrations occur in Bristol Bay, Norton Sound, Kotzebue Sound, and Kasegaluk Lagoon.
It is not unusual for belugas to ascend large rivers such as the Yukon, and they seem to be unaffected by salinity changes. Although upriver movements appear to be less common than a century ago, in 1982 a group of whales was seen at Tanana, 750 miles (1,200 km) from the river mouth, and a single adult was seen above Rampart, 80 miles (130 km) farther upstream. In 1993, four belugas were seen near Fort Yukon.
Behavior: Belugas sometimes occur in herds of up to 1,000 individuals, although small groups of two to five are common. The social structure of these groups is not well known, but it is known that adult males often swim together in pods of eight or ten, and adult females occur in pods with juveniles and calves. Belugas often swim four to six abreast, rolling simultaneously to breathe. Sometimes when they are in shallow water or feeding, only their blowholes break the surface when they breathe, making them very difficult to see. This is called “snorkeling.” These whales spend only about 4 to 7 percent of their time at the surface.
Belugas can move long distances. Some migrate over 1,500 miles (2,700 km) from the Bering Sea to the Mackenzie River estuary in Canada. In Bristol Bay, they sometimes swim over 100 miles (180 km) per day. In summer 1993, one satellite-tagged beluga swam all the way from the Mackenzie River to the eastern Canadian arctic, where it was seen swimming with narwhals. It then returned to Alaska waters.
Belugas are very vocal animals, producing a variety of grunts, clicks, chirps, and whistles which are used for navigating, finding prey, and communicating. Because of this, they have sometimes been called “sea canaries.”
Abundance and human use: The Cook Inlet population of belugas is estimated to number 400 to 500 animals. The much larger Bering Sea population is more difficult to count. Counts of animals in summering areas indicate 13,500 to 21,000 belugas in coastal waters of Canada and western Alaska. If animals summering in waters of Siberia are included, the total population may exceed 25,000 animals.
Belugas are harvested in Alaska by Eskimos living in coastal villages from Cook Inlet to Barter Island. Hunting is done in spring as whales travel northward through channels of water through the ice, as well as during the summer and autumn open-water period. Recent harvest levels in Alaska have averaged about 150 to 250 animals per year. In addition, approximately 140 whales were taken annually in the Mackenzie River estuary. An unknown, but probably small, number is harvested along the coast of Siberia. Including animals that are killed but lost during the hunts, annual removals from the western arctic population have been 600 to 700 animals in recent years. These removals are probably below the sustainable yield which has been estimated to be about 5 percent per year. In Alaska, there is a committee of hunters and scientists (the Alaska and Inuvialuit Beluga Whale Committee) that is working together to manage, conserve, and learn more about beluga whales.
Belugas are principally used for human consumption, either as meat or “muktuk,” which consists of skin and the outer layer of blubber. The oil is used for cooking and for fuel.
Belugas are an important component of the nearshore marine mammal fauna of Alaska waters. The continued existence of healthy beluga populations depends on protection of important habitats, avoiding conflicts between belugas and human developments in nearshore and offshore waters, and wise use of the resource.
Text: Lloyd Lowry
Illustration: Jim Fowler
Revised and reprinted 1994
