Large numbers of humpback whales are remaining in bays along the Western Antarctic Peninsula to feast on krill late into the austral autumn, long after their annual migrations to distant breeding grounds were believed to begin, according to a new Duke University study. The study, published July 30 in the journal Endangered Species Research, provides the first density estimates for these whales in both open and enclosed habitats along the peninsula in late autumn.
Large numbers of humpback whales are remaining in bays along the Western Antarctic Peninsula to feast on krill late into the austral autumn, long after their annual migrations to distant breeding grounds were believed to begin, according to a new Duke University study.
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The study, published July 30 in the journal Endangered Species Research, provides the first density estimates for these whales in both open and enclosed habitats along the peninsula in late autumn.
It suggests that the little-studied bays are much more important late-season feeding grounds for humpback whales than scientists previously thought. It also highlights changes that are occurring in the region in response to the increasingly delayed arrival and reduced extent of annual winter sea ice cover, associated with rapid climate change.
"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 David W. Johnston, research scientist at Duke's Nicholas School of the Environment and lead author of the paper.
Large numbers of humpback whales are remaining in bays along the Western Antarctic Peninsula to feast on krill late into the austral autumn, long after their annual migrations to distant breeding grounds were believed to begin, according to a new Duke University study.
Photo credit: MISHAP Project, under permit from NOAA.
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