Gray whale

Intensive exploitation has much reduced population numbers of this species over the last three to four centuries. Of the original three gray whale populations, one is extinct in the North Atlantic, one is critically endangered in the Western North Pacific (with as few as 130 individuals remaining), and one has recovered from very low levels in the Eastern North Pacific and was removed from the U.S. Endangered Species List in 1994.
 
Only around 130 Western Gray Whales are left worldwide, including some 20 females able to ... rel=
About 130 Western gray whales survive, including only 26 breeding females.
© WWF-Canon / Michel Terrettaz

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Key Facts

  • Common Name

    Gray whale

  • Scientific Name

    Eschrichtius robustus

  • Status

    IUCN: Critically endangered (western subpopulation)

    Read more

  • Population

    Approximately 26,000 individuals (about 130 individuals western population)

  • Length

    12.2 and 15.2 m

  • Skin colour

    Mottled gray

Physical Description

The gray whale appears very different from any other whales and indeed is contained in its own taxonomic family. Instead of a dorsal fin, gray whales have a dorsal hump followed by nine to 13 bumps along their dorsal ridges. They produce a range of sounds including moans, rumbles and growls. The most prevalent call is a series of knocking sounds. Gray whales were known by whalers as "devilfish" because they defended themselves and their calves so fiercely.

Gray whales in the Baja California region are known as being "friendly" – they have an unusual tendency to approach whale-watching boats and even let whale-watchers touch them and scratch their tongues.

Size

These whales grow to between 12.2 and 15.2 m, with females about 1 m longer than the males.

Colour

They are mottled gray, while whale lice and parasitic barnacles create light coloured patches on their bodies.
Tourists watch from small boats as a gray whale surfaces in  Baja California, Mexico. / ©: Gustavo YBARRA / WWF-Canon
Tourists watch from small boats as a gray whale (Eschrictius robustus) surfaces in Baja California, Mexico.
© Gustavo YBARRA / WWF-Canon

Ecology & Habitat

Can still fall prey to killer whales

As shallow-water feeders, gray whales stay close to coasts.

Life Cycle

Gray whales become sexually mature at around eight-years old. Calves can swim as soon as they are born and can double their weight in about three months, and double their length in about two years. Mother and calf form a very close attachment, with the calf spending the majority of its time swimming close to its mother.

It's difficult to tell how old gray whales are because they have no teeth (which can be used to estimate age in other mammals). They may die of natural causes but sometimes fall prey to killer whales.

Breeding

During the summer, gray whales are found alone or in small groups. It has been suggested that mating occurs in the winter, and some mating activity has been witnessed in the breeding lagoons. Pregnant females return to the feeding grounds for the summer, returning to breeding areas to calve the following winter. The gestation period lasts for about 13 months, and they breed every two to four years.

Diet

Gray whales, like other baleen whales, strain their food from the water through baleen plates. However, they are different from other shallow feeding great whales in that they prefer prey that lives near or on the sea floor. They are the only large whale that feeds primarily on the ocean floor, rolling in the mud to suck benthic organisms from the sea bottom.

Priority species

Whales and dolphins are a priority species. WWF treats priority species as one of the most ecologically, economically and/or culturally important species on our planet. And so we are working to ensure such species can live and thrive in their natural habitats.
Sea of Okhotsk shore, Sakhalin island, Russian Federation. / ©: Vladimir FILONOV / WWF-Canon
Sea of Okhotsk shore, Sakhalin island, Russian Federation.
© Vladimir FILONOV / WWF-Canon

Population & Distribution

Highly organized migratory system

Previous population and distribution

The species was decimated in the North Atlantic during the last 300-400 years. Very little is known regarding its disappearance. Whaling records show no evidence that the Atlantic gray whale was hunted in huge numbers that would have caused its extinction. If it relied on shallow breeding lagoons, it is possible that its habitat disappeared and whaling simply hastened its extinction.

Current population and distribution

The eastern North Pacific stock of gray whales prefer shallow, coastal waters and feed over the oceanic continental shelves of the Bering and Chukchi seas between Alaska and Russia during the summer. In the winter, many migrate along the west coast of the US, Canada, and Mexico, a distance of several thousand miles.

Gray whales have one of the longest annual migrations of any species - only humpback whales have been known to occasionally travel longer distances between their feeding and breeding grounds.

There are encouraging signs of population recovery of the eastern stock, which numbers approximately 26,000 individuals. This is occurring despite an annual hunt in Russia, regulated by an International Whaling Commission quota.

A cause for concern recently is the mortality sustained by the species on its migration route and in the winter breeding areas, and the decline in newborn calves. This could herald a potential decline in abundance of the eastern Pacific stock, or may be the result of natural mortalities indicating that the population has reached its carrying capacity.

Western gray whales migrate into their summer feeding grounds near Sahkalin Island, Russia, in late May or early June, returning to their winter feeding grounds in the South China Sea in late autumn.

Some scientists have suggested there may be a breeding ground for this population along the coast of southern China, but to date no breeding area has been located. It is not known whether the western population relies on shallow coastal lagoons for breeding, as is the case for the eastern Pacific population.
Gray whale distribution. / ©: Wikipedia
Gray whale distribution (in blue).
© Wikipedia
 / ©: WWF-Canon / Michel Terrettaz
There could be less than 130 Western gray whales (Eschrictius robustus) remaining.
© WWF-Canon / Michel Terrettaz

What are the threats to the gray whale?

Shipping and whale lanes: deadly crossings for cetaceans

Like other large whales, gray whales are now threatened by environmental change, including habitat loss and toxics, and are also harmed by ship strikes and entanglement in fishing gear, especially during their annual migrations through the coastal waters of Japan, Korea, and China.

The Eastern North Pacific population of gray whales, numbering more than 20,000 whales, is a great conservation success story and was removed from the United States Endangered Species List in 1994. Today they are subject to a small aboriginal hunt off the coast of the northwestern US.

The Western North Pacific gray whale population is currently most severely threatened. Seismic activity from a major oil and gas field in its principal summer feeding area off Sakhalin Island in Russia's Okhotsk Sea posed a significant threat to the population.
Oil and gas

Sakhalin II is an extensive multinational project in eastern Russia that includes platform dredging, an undersea pipeline to be trenched through the benthic feeding habitat of the north-west Pacific gray whale population, and the dumping of drilling wastes into the sea. Operating in difficult climate and seismic conditions, including high earthquake activity, heavy ice pack, frequent storms and fog, the project presents risks of a catastrophic oil spill not unlike that of the Exxon Valdez.

Read more...

What is WWF doing?

WWF and its conservation partners have been instrumental in strengthening protection for the Western North Pacific gray whales. We were successful in curtailing seismic surveys that were shown to displace gray whales from their feeding ground and have been urging the Russian government to establish a gray whale sanctuary off Sakhalin Island.

Other activities include pushing for stricter environmental standards for offshore oil and gas projects, engaging a local energy company regarding their operations, and running a public campaign to raise awareness regarding the threats posed by the Sakhalin offshore oil and gas projects pose to whales.

A group of people holding a banner with the words "Say No to EBRD Financing" / ©: Sakhalin Environment Watch
Sakhalin Environment Watch protest march: "Say No to EBRD Financing"
© Sakhalin Environment Watch

How you can help

  • Support efforts to improve fishing gear by only buying seafood that is MSC certified. This can help to reduce the incidence of marine bycatch, which kills whales and other marine life like turtles, dolphins, and seabirds.
     
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