Globally distributed, globally depleted
Previous Population and DistributionRelentlessly pursued by 20th century whaling fleets, the blue whale was nearly exterminated before receiving worldwide protection in 1967. From 1904 to 1967, more than 350,000 were killed by whaling fleets in the Southern Hemisphere. It is thought that thousands more were killed by Soviet fleets during the 1960s and 1970s.
Pre-whaling population may have been more than 250,000 strong. In 1931, during the heyday of whaling, an astounding 29,000 blue whales were killed in one season. In total, about 360,000 blue whales were killed in the 20th Century in the Antarctic alone.
Current Population and Distribution
The blue whale has a truly global distribution, occurring in the Arctic Sea, Atlantic Ocean (Antarctic, eastern central, northeast, northwest, southeast, southwest, western central), Indian Ocean (Antarctic, eastern, western), and Pacific Ocean (Antarctic, eastern central, northeast, northwest, southeast, southwest, western central).
In spite of their global distribution, they are one of the rarest of the whales, and most biologists consider them to be among the most endangered of the great whales. Only one population, in the eastern North Pacific off California, is showing real recovery and currently numbers about 2,000 animals.
Some of the remaining blue whales are of a subspecies known as "pygmy" blue whales. As their name suggests, they are somewhat less gigantic than "true" blue whales, and until recently were thought to be confined to the Indian Ocean region; however, recent studies indicate they may be more widespread.
Only a few hundreds are thought to be found in the Antarctic, and while they have been increases around Iceland and off the coast of California, none are to be found off Japan, the Gulf of Alaska and the southern Bering Sea.