Palo Alto, Calif. – The heralded success story of the Pacific gray whales’ full recovery from near-extinction might be wrong, according to a new genetic analysis that pegs the current population at only one-third to one-fifth of historical levels.
By examining subtle variations among DNA taken from 42 modern whales, scientists have concluded that between 78,500 and 117,700 gray whales lived before the heyday of commercial whaling in the Pacific in the 19th and 20th centuries.
That finding, published today in the Proceedings of the National Academy of Sciences, suggests that the roughly 22,000 gray whales swimming along the California coast remain a depleted population in transition.
The results counter what had been a predominant scientific view that the whales had become so bountiful that they were damaging their traditional feeding grounds by overgrazing.
“If the oceans a few hundred years ago could support 100,000 gray whales, why can’t the oceans sustain 20,000 whales today?” said Stephen Palumbi, a senior author of the study.
Researchers used computers to calculate the number of ancient breeding whales that would have been necessary to produce the variety of genetic patterns obtained in their samples. Factoring in that some adults don’t breed, the proportion of juveniles and other factors, they concluded that at least 78,500 and no more than 117,700 gray whales must have roamed the Pacific at least 1,600 years ago.
The gray whale population plummeted to 17,400 after starving whales began washing ashore in 1999 and 2000.
