NEWPORT, Ore. More than 99 percent of Antarctic blue whales were killed by commercial whalers during the 20th century, but the first circumpolar genetic study of these critically endangered whales has found a surprisingly high level of diversity among the surviving population of some 2,200 individuals.
That, says lead author Angela Sremba of Oregon State University, may bode well for their future recovery.
Results of the study have just been published in the open-access journal, PLoS ONE. As part of the study, the researchers examined 218 biopsy samples collected from living Antarctic blue whales throughout the Southern Ocean from 1990 to 2009, through a project coordinated by the International Whaling Commission.
The genetic survey revealed a "surprisingly high" level of diversity that may help the population slowly rebound from its catastrophic decimation by whalers.
"Fewer than 400 Antarctic blue whales were thought to have survived when this population was protected from commercial hunting in 1966," noted Sremba, who conducted the research as part of her master's degree with the Marine Mammal Institute at OSU's Hatfield Marine Science Center. "But the exploitation period, though intense, was brief in terms of years, so the whales' long lifespans and overlapping generations may have helped retain the diversity."
"In fact," she added, "some of the Antarctic blue whales that survived the genetic bottleneck may still be alive today."
Prior to whaling Antarctic blue whales were thought to number about 250,000 individuals a total that dwindled to fewer than 400 animals by 1972 when the last blue whales were killed by illegal Soviet whaling. Blue whales are thought to be the largest animals ever to have lived on Earth, said OSU's Scott Baker, associate director of the Marine Mammal Institute and an author on the study and the Antarctic blue whales were even larger than their cousins in other oceans
|Contact: Scott Baker|
Oregon State University