NFB - Arctic Mission

by Isabelle Deslandes, Ship's doctor

The bowhead whale, also known as the Greenland right whale, is a robust marine mammal that averages 15 metres in length and weighs up to 90,000 kg. With its 50 cm thick layer of insulating fat called blubber, this cetacean is well adapted to life in the frigid waters of its habitat. Its massive head makes up a third of its total body length. Bowhead whales have white markings on their lower jaw, fluke and tail stock that increase in size with age. The lack of callosities distinguishes them from the other right whales. These baleen whales have a triangular fluke with smooth margins that measures up to 8.5 metres in width, and they don’t have a dorsal fin. As they come to the surface to breathe, their V-shaped spout can shoot up to 6 metres in the air.

The bowhead whale is recognized by its white lower jaw with black markings. It has been an endangered species since the days of commercial whaling. A few hundred individuals visit the region of Foxe Basin in Nunavut each year. The bowhead whale is rather solitary and only associates with other whales for a few hours or, at most, a few days at a time, an obvious exception being the relationship between mother and calf. This strong maternal bond lasts around 9 to 12 months, after which time the calf is weaned and they each go their separate ways. Bowhead whales become sexually mature in their second decade of life. Females generally give birth to a single calf every three to four years after a gestation period of approximately one year. Individuals can communicate over several miles using a complex system of vocalizations such as that produced by males in the spring. Scientists believe that these melodious songs are intended to attract a potential mate. It is believed that similar vocalizations are used as primitive echolocation to detect possible obstacles in their path, such as icebergs, well before they become visually perceptible.

Bowhead whales are observed in a circumpolar distribution in the Arctic and sub-Arctic regions, between the 60th and 85th parallels. They winter in the southern limits of the ice fields and, as the ice breaks up and recedes in the spring, they migrate back to their northern foraging grounds. Bowhead whales have a predilection for loose ice fields with leads and cracks at the edges of ice floes. They travel slowly, averaging speeds of 5 to 7 kilometres per hour.

Two bowhead whales surfacing at the floe edge in Igloolik. What do bowhead whales eat? Their diet consists primarily of small copepods but also includes krill and other varieties of zooplankton. Bowhead whales, being part of the Mysticetes family, are filter feeders. They spend long periods of time under water skim feeding by passing food particles through their long, fine baleen plates. These impressive comblike structures suspended from the roof of their mouth measure up to 4 metres in length.

Intensive commercial whaling led to the killing of thousands of bowhead whales in the North Atlantic and Arctic oceans. Of the five known populations in the world, four remain greatly affected as a result and are still highly endangered. It is estimated that the population that lives around Foxe Basin in Nunavut is composed of probably just a few hundred individuals. Over the last 40 years, great efforts have been made to protect this species. A proposed whale sanctuary in Isabella Bay near Clyde River may one day help to further research and protect the bowhead whale, a species that reflects the fragility of the Arctic ecosystem.