Antarctic minke whales not increased due to hunting of other larger whales

Washington, January 18 (ANI): A new genetic analysis of Antarctic minke whales has concluded that population of these smaller baleen whales have not increased as a result of the intensive hunting of other larger whales.

Antarctic minke whales are among the few species of baleen whales not decimated by commercial whaling during the 20th century, and some scientists have hypothesized that their large numbers are hampering the recovery of deleted species, such as blue, fin and humpback, which may compete for krill.

This "Krill Surplus Hypothesis" postulates that the killing of some two million whales in the Southern Ocean during the early- and mid-20th century resulted in an enormous surplus of krill, benefiting the remaining predators, including Antarctic minke whales.

But the new analysis estimates that contemporary populations of minke whales are not "unusually abundant" in comparison with their historic numbers.

Using a novel genomic approach, the scientists were able to calculate the long-term population size of Antarctic minkes as roughly 670,000 individuals, which is similar to estimates of current population size from sighting surveys.

"Some scientists involved in the International Whaling Commission have suggested that Antarctic minke whales have increased three-fold to eight-fold over the last century because of the lack of competition for krill," said Scott Baker, a whale geneticist at Oregon State University and associate director of the Marine Mammal Institute at OSU.

"But until now, there has been little evidence to help judge what historic populations of minke whales actually were," he added.

"Our study clearly shows that minke whales today have a great deal of genetic diversity, which reflects a long history of large and relatively stable population size," he said.

"The bottom line is that the Krill Surplus Hypothesis does not appear to be valid in relation to minke whales and increasing hunting based solely on the assumption that minke whales are out-competing other large whale species would be a dubious strategy," Baker said. (ANI)