Bowhead Whale | Oceana Canada

Canadian Marine Life Encyclopedia

Bowhead Whale

Balaena mysticetus

Also known as

Greenland whale, Greenland right whale, polar whale

Distribution

Throughout the Arctic ocean

Ecosystem/Habitat

Offshore, near ice edge

Feeding Habits

Filter feeder

Conservation Status

Special concern/data deficient

Taxonomy

Suborder Mysticeti (baleen whales); Family Balaenidae (right whales)

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The bowhead whale’s name comes from the bow-shape of its large upper jaw. Its jaw holds the longest baleen plates of any whale, reaching up to four meters long! Bowhead whales use these plates to filter water for food, like zooplankton, krill and small fish. Their large heads makes up one third of their body length and are encased by a thick layer of blubber. This allows them to explore waters farther north than other whales, which helps them to avoid predators like killer whales. Bowhead whales also use their large heads to smash through ice  more than 20 centimetres thick. This ice smashing often leaves bowhead whales with distinct scars that scientists use to identify different individuals. 

Bowhead whales are less streamlined than other baleen whales. Their blackish-blue, stocky bodies have small flippers and no dorsal fin. They have thick blubber, up to 50 centimetres in some areas, and white markings on their chin, fins and underbelly. Their lower and upper jaws each have around 330 baleen plates, which can grow up to four metres long. Females grow faster and larger than males and can be up to 20 metres long and weigh 100 tonnes.

Bowhead whales can live for more than 100 years, only reaching sexual maturity at around 25 years old. They are slow reproducers: females give birth approximately once every three years with gestation lasting from 12 to 16 months. Calves are born between four and four and a half meters in length without their distinct white markings that develop as they age. Calves are usually born in time for the spring migration to northern feeding grounds, which takes place between April and June. When the ice melts in the spring, new areas open up and the whales are able to travel farther north to waters rich with krill, zooplankton and small fish. In their northern ranges, the distribution of bowhead whales mirrors that of their prey, making them a good indicator species for the health of the Arctic food web. This means that the presence of bowhead whales is a good indication that the habitat is healthy and productive, allowing krill, zooplankton and small fish to flourish and feed other animals in the food web. As the sea ice begins to solidify again in autumn, bowhead whales travel south once more to their breeding grounds. 

Bowhead whales have long been targeted by humans for food and other purposes because they are slow swimmers with high blubber content that helps them float. They have been targeted by subsistence Inuit hunters since as early as 1100 A.D., but were severely depleted when the commercial whaling industry took off in the mid-19th century. As a result of careful management, both the Eastern and Western populations have recovered enough to sustain a small subsistence harvest in Canada. Harvesting bowhead whales is important for Inuit and other northern peoples to retain cultural and traditional practices. All parts of a whale are used and nothing is wasted: for example, bones can be used for tools such as sled runners and shelter scaffolding, oils for heat and light, blubber for food, and baleen for rope. Climate change has resulted in a warmer Arctic with less sea ice. The increased access to northern areas that were once inaccessible due to ice has intensified industrial activities. As Arctic waters become busier, bowhead whales could be at a greater risk of a vessel strike or entanglement, as well as being affected by noise pollution. 

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) has assessed both bowhead whale populations in Canadian waters as of Special Concern. Yet, only the Bering-Chukchi-Beaufort Sea population has been listed under the Species at Risk Act (SARA), where it was designated under Schedule 1 as of Special Concern.