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.