Humpback whale. Photo by Rhett A. Butler
Humpback whales in the Antarctic are delaying their migration to feed on krill that are staying later due to reduced extent of sea ice, a possible consequence of climate change, reports a study published in the journal Endangered Species Research [PDF.
The research, which was led by David W. Johnston of Duke University, found that whales occur in high densities in bays along the Western Antarctic Peninsula late into the austral autumn, much later than thought.
“The old dogma is that by late autumn, the ice is heading in and the whales have headed out. But 70 percent of our surveying took place in waters with no ice, and we detected 371 groups of humpback whales over a 654-kilometer survey area, with density estimates of up to 1.75 whales per square kilometer,” said Johnston in a statement. In contrast, the lowest densities were found in open water areas.
The results could help establish a baseline for measuring future change in the ecosystem.