Aquatic Species at Risk - Blue Whale (Pacific)

Species - Details

Blue whale
Fisheries and Oceans Canada

Scientific name:
Balaenoptera musculus
Taxonomy:
Mammals (marine)
SARA Status:
Endangered (2005)
COSEWIC Status:
Endangered (2002; 2012)
Region: Pacific

Did You Know?

Blue whales eat krill: shrimp-like crustaceans about two centimetres long. A single Blue whale can consume as much as four tons of krill in a day. They do so by taking large quantities of water into their mouths and then forcing it back out through their baleen. The baleen act as strainers, catching any krill or other planktonic organisms in the water; these are then swallowed.

At a glance

The Blue whale is the largest animal on Earth today—and the largest known to have ever existed. Hunted relentlessly for hundreds of years, the species remains endangered today, although there is now an international ban on taking Blue whales. Sightings of Blue whales off Canada’s Pacific coast have been rare in recent years, suggesting that population numbers have fallen quite low.

About the Blue whale

Blue whales travel in herds, migrating between polar waters in summer and more temperate waters in winter. They can swim at speeds of up to 36 km/h, but typically cruise between two and eight km/h.

The Blue whale isn’t just big; it’s also loud. It can emit sounds at up to 186 decibels—46 decibels louder than a jet aircraft. To date, researchers have not been able to determine why the whales make these calls.

Blue whales generally dive for five to 15 minutes, although submersions for as long as 36 minutes have been recorded in the St. Lawrence.

Living between 70 and 80 years, Blue whales reproduce every two or three years. Calves at birth measure seven metres and weigh some two tonnes. The largest adult on record measured 29.5 metres.

How to recognize the Blue whale

The Blue whale is a rorqual whale—one of a group that has expanding grooves in the skin of the neck; these allow it to take in huge volumes of water while feeding. One quarter of its entire length is made up by its head. It has a smallish dorsal fin and pointed pectoral flippers. Despite its name, the Blue whale is actually coloured dark and light grey; every whale has a unique pattern of mottling that makes it identifiable.

Blue whale
Fisheries and Oceans Canada
Blue whale - Jean-François Gosselin
Jean-François Gosselin
Blue whale - Kelly Houle, NOAA Northeast Fisheries Science Center
Kelly Houle, NOAA Northeast Fisheries Science Center
Blue whale - Jean-François Gosselin Jean-François Gosselin

Where the Blue whale lives

Blue whales live in every one of the world’s oceans. There are three subspecies. Those found in Canada belong to the Northern Hemisphere subspecies—of which there are both North Atlantic and North Pacific populations. The Pacific population is found off the west coast of Canada; it migrates past Vancouver Island in spring and fall. The Blue whale population off Mexico and California is estimated to be between 1,500 and 3,000, but no accurate count has been made of the western Canadian population.

Why it’s at risk

Past commercial whaling of Blue Whales is the main factor responsible for the population decline. Throughout the North Pacific between 1910 and 1965, commercial whalers harvested at least 9,500 Blue Whales, some of which were caught by shore-based whaling stations in British Columbia from the early 1900s to 1965. Since the end of commercial whaling, human threats have included collisions with ships, increasing whale-watching activity, entanglement in fishing gear, and pollution (especially oil pollution).

What’s being done

The Blue whale is listed as endangered and protected under the Species at Risk Act (SARA). It is also protected under the Marine Mammals Regulations, which fall under the Fisheries Act. In the North Pacific, whaling of this species was prohibited in 1966. Internationally, Blue whales are protected by the International Whaling Commission; the Blue whale is also listed by both the World Conservation Union (IUCN) and the Convention on the International Trade of Endangered Species (CITES).

What can you do?

This species will get the protection it needs only if all Canadians work together to reduce threats. Find out more and do your best to reduce these threats wherever possible to better protect its critical habitat. Get involved with the Habitat Stewardship Program for Species at Risk (HSP) or another conservation organization.

Background information provided by Environment Canada in March 2004.