Aquatic Species at Risk - Grey Whale (Eastern North Pacific Population)

Species - Details

Grey Whale

Scientific name:
Eschirichtius robustus
SARA Status: Special Concern (July 2005)
COSEWIC Status: Special Concern (May 2004)
Region: Pacific Ocean, Arctic Ocean

Did You Know?

Straining for dinner
Grey whales use their baleen plates like a strainer to filter sediment and locate their prey such as tiny crab-like animals called amphipods and worms. They scoop up mouthfuls of sediment and allow it to sift through the spaces between the baleen, with only the prey left behind in their mouths.

Toothless wonder
The whale has no teeth to chew its food, so must swallow it whole. Instead of teeth, the whale has a baleen. The baleen is made up of long fibers much like a broom. It acts as a filter. When the whale’s mouth is full, it closes forcing the water out. The small organisms the whale eats get caught in the baleen. When all the unwanted material has left the mouth, the whale swallows.

This species has been identified as Special Concern by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). It is listed under the federal Species at Risk Act (SARA) and was afforded protection under SARA as of July 2005. Additional protection is afforded through the federal Fisheries Act. As required under SARA, a management plan has been developed for this species.

General Description

Grey Whale

Eschrichtius robustus - Illustration by J. Domm

The Grey Whale (Eschrichtius robustus) is a medium to large baleen whale (Mysticete) and the only species still in existence in the family Eschrichtiidae. In the North Pacific, Grey Whale fossils date back at least 50,000 years before present. Indigenous names for the species include ‘mauk’ (Nuu-chah-nulth), ‘balgina’ (Kwakw’ala – western dialects), ‘cetuqupak’ (Yup’ik) and ‘abvibluaq’ (Iñupiaq). It has the following characteristics:

  • Series of 7 to 15 ‘knuckles’ along the dorsal ridge, but no dorsal fin;
  • Baleen plates are short and cream to pale yellow in colour;
  • Two to four throat grooves which allow the throat to extend during feeding;
  • Dark to light grey with various degrees of mottling and scarring; often covered with patches of barnacles and crustaceans; and
  • Females are somewhat larger than males; between 11.7 and 15.2 m in length compared to 11.1 to 14.3 m for males.

Distribution

Distribution of the Grey Whale Pacific population as described in the following paragraph

Grey Whales occur in two distinct populations: the western and eastern North Pacific. The western North Pacific population is estimated at only 100 individuals who migrate between winter breeding grounds off southern China, to summer feeding grounds in the Sea of Okhotsk. Only the eastern North Pacific population occurs in Canadian waters. The current size of the eastern population is approximately 20,000 whales. Its wintering and breeding grounds are along the west coast of Baja California, Mexico, in a series of shallow lagoons. The peak of its southbound migration is in late December and early January. Between February and May, the Grey Whale heads north, usually within a few kilometres from shore. During the summer, most whales feed in the shallow waters of the Bering, Chukchi, and Beaufort seas. A few hundred animals, called the summer-resident community, feeds in temperate waters from California to southeastern Alaska, including near-shore waters in B.C.

Habitat and Life History

Grey Whales are migratory and require different habitats for reproducing and feeding. The arctic feeding grounds are characterized as being shallow (less than 60 m) with soft or sandy substrate. On temperate feeding grounds in British Columbia, grey whales use all types of near-shore habitats, rocky or muddy bottoms to kelp beds. The breeding lagoons are in shallow, sheltered bays, with sandy or mud substrate covered in places by eelgrass beds and mangrove swamps. Grey whales reach sexual maturity at about eight years. The gestation period lasts 13 to 14 months, and in late winter of alternating years, females give birth to one calf. The calf is weaned in late summer on the feeding grounds. Lifespan is as long as 70 years.

Diet

The Grey Whale is the only species of baleen whale that regularly feeds on organisms living on or near the bottom. This is accomplished by scooping the sediment and straining it through their baleen. Most feeding occurs in the summer on the arctic feeding grounds, where Grey Whales primarily consume amphipod crustaceans. They may also forage on sand shrimp. Diet becomes more varied during the northward migration and on temperate feeding grounds, and can include amphipods, herring eggs and larvae, mysid shrimps, ghost shrimps and crab larvae.

Threats

Historically, commercial whaling severely reduced the eastern Pacific grey whale population to critically low levels (less than 2,000 animals). While commercial whaling no longer threatens them, human activities remain an important factor affecting grey whales and their habitats. Salt extraction, oil exploration, offshore mining, toxic spills and industrial noise in shallow marine areas can cause loss and deterioration of breeding and feeding habitats and potentially could affect migration routes. In addition, collisions with ships and entanglement in fishing gear can result in mortality. Prolonged ice cover on the arctic feeding grounds limits the feeding season.

Similar Species

There are no similar species.

Text Sources: COSEWIC Assessment & Status Report 2004.

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