The Bowhead Whale (Hudson Bay-Foxe Basin Population)

This species has been identified as Threatened by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). It is currently being considered for listing under the federal Species at Risk Act (SARA). Protection is afforded through the federal Fisheries Act. If listed under the Species at Risk Act (SARA), it will be afforded additional protection. Under the SARA, a recovery strategy must be developed for this species.

General Description

Balaena mysticetus

Illustration by G. Kuehl
© Fisheries & Oceans Canada

Bowhead Whales (Balaena mysticetus) are large baleen whales of the Balaenidae family. Other common names include the Greenland Whale, Greenland Right Whale and Polar Whale. In northern Aboriginal languages, it is known as Arviq or Arvik (Inuktitut and Inuvialuktun), Agkhovik (Inupiat), Akhgvopik (Yupik) and Ittiv (Chukchi). Bowhead Whales have the following characteristics:

• Barrel-shaped body and a very large head (about 30% of total body length)
• Upper jaw is bowed sharply upward; each side of upper jaw has on average 330 baleen plates up to 427 cm long
• The blubber layer is thick, from 5.5 cm on the chin to about 28 cm over the trunk reaching a maximum of 50 cm
• Flippers are small and paddle-shaped
• No dorsal fin or dorsal hump
• Flukes are pointed at the tip
• Calves are 4 to 4.5 m long at birth and brownish black in colour
• Adults are black in colour with white areas near the chin, eyelids, flipper insertions, ano-genital area, tail stock and flukes

Distribution

The Bowhead Whale has a nearly circumpolar distribution in the northern hemisphere and ranges from 54^o to 85^oN latitude. Physical barriers such as land and impassable ice are believed to have divided the world’s bowheads into five populations, three of which occur in Canada: the Hudson Bay-Foxe Basin, Davis Strait-Baffin Bay and Bering-Chukchi-Beaufort Sea populations. The extent of occurrence of the Hudson Bay-Foxe Basin population is roughly 352,070 km². These whales are believed to overwinter in Hudson Strait. During April through May, some migrate west until they reach northwestern Hudson Bay around Roes Welcome Sound, Repulse Bay and Frozen Strait while others move north into northern Foxe Basin (north of Igloolik). Some whales move through Fury and Hecla Strait into Prince Rupert Inlet for the summer. In September and October, whales migrate east of Roes Welcome Sound and south from Foxe Basin into Hudson Strait.

Bowhead Whale Distribution: Hudson Bay-Foxe Basin

Habitat and Life History

Bowhead Whales occur in marine waters within areas ranging from open water to thick, unconsolidated pack ice. They break through ice over 20 cm thick with the crown of the head to breathe, and can navigate and communicate under extensive ice fields using their sophisticated acoustic sense. They grow and develop slowly, reaching sexual maturity at about 25 years of age. Females grow faster than males and give birth approximately once every three years during the spring migration. Gestation lasts between 12 and 16 months. Longevity is estimated to be between 50 and 75 years, with some individuals possibly reaching over 100 years of age.

Diet

The Bowhead Whale feeds on crustacean zooplankton, such as euphausiids and copepods, as well as epibenthic organisms (mysids and gammariid amphipods). It has been suggested that the annual variability in Bowhead Whale sightings is related to the abundance and distribution of zooplankton.

Threats

Commercial whaling was once the greatest threat to the Bowhead Whale and the main reason why the species is at risk in parts of its range. The greatest threat to this population at present is an increased vulnerability to predation by the Killer Whale (Orcinus orca) as a result of reduced ice coverage. Climatic factors may also influence prey availability.

Similar Species

There are no similar species. 

Text Sources: Thomas 2005 (COSEWIC Status Report).

For more information, visit the SARA Registry Website at www.SARAregistry.gc.ca.