Grey whales

1 min read
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As per a new study, population swings in eastern North Pacific grey whales — some of which have resulted in recent mass mortality events — are driven by changing prey biomass and ice cover in the Arctic.

About Grey whales: 

  • Gray whales have a hump and a ridge of sharp bumps along their backs, instead of a dorsal fin.
  • They are a type of baleen whale, which means they filter food from the water through special bristly structures in their mouths
  • They stay close to shore and feed in shallow water.
  • They are found mainly in shallow coastal waters in the North Pacific Ocean, although during migration, they do sometimes cross deep waters far from shore.
  • There are two geographic distributions of gray whales in the North Pacific:
    • The eastern North Pacific stock or DPS, found along the west coast of North America.
    • The western North Pacific stock or DPS, primarily found along the coast of eastern Asia.
  • Migration journey
    • They are well-known for migrations that take them between feeding and breeding areas, swimming as much as 12,000 miles round trip.
    • Western gray whales migrate into their summer feeding grounds near Sahkalin Island, Russia in late May or early June and return to their winter feeding grounds in the South China Sea in late autumn.
    • Summer feeding grounds for the eastern population lie in the Bering and Chukchi Seas between Alaska and Russia.
    • In the winter, these eastern gray whales migrate south along the west coast of the US to Mexico to breed and have their calves.
  • Conservation status
    • IUCN: Western Grey whale (Critically endangered) and Eastern Grey whale (Least concern)


Q1) Where is Sakhalin Island?

Sakhalin Island, also known as Sakhalin, is a large island located in the North Pacific Ocean, just off the eastern coast of Russia. It is Russia's largest island and is situated to the north of Japan, separated by the Sea of Japan.

Source: Arctic ecosystem impacts grey whale population