Krill on the menu for Antarctic minke whales’ lunge diet
The extraordinary feeding behaviour of Antarctic minke whales has been recorded for the first time, showing the mammals lunge feeding up to 100 times per hour under the sea ice, gorging on Antarctic krill.
Scientists from the United States and Australia attached multi-sensor suction cup satellite tags to minke whales off the west Antarctic Peninsula last year to study their foraging patterns.
Australian Antarctic Division Chief Scientist, Dr Nick Gales, said the tags measured the whales’ orientation, depth and acceleration.
“Prior to this work the movements and diving behaviour of these whales was something of a mystery as no tags had been deployed on the species,” Dr Gales said.
“We found that the minkes were swimming just beneath the sea ice, feeding at incredibly high rates, taking mouthfuls of krill every 30 seconds.
“This is very different from other whale behaviour, for example the gigantic blue whales lunge up to four times during a dive and smaller humpbacks lunge up to 12 times.”
The study also found the minkes’ size and manoeuvrability allows them to take advantage of the sea ice habitat.
“The minke’s preferred prey, Antarctic krill, aggregate under the sea ice and attract the whales to the area, leading to these feeding frenzies,” Dr Gales said.
“But any future change in sea ice has the potential to impact on the minke whales’ foraging habits.”
The study is part of the Australian-led Southern Ocean Research Partnership, which is focused on non-lethal research and is endorsed by the International Whaling Commission.
“It’s clear from the insight we have gained into the whales’ behaviour through this work, that you simply don’t have to kill the whales to study them,” Dr Gales said.
The study was published in the Journal of Experimental Biology.
The Southern Ocean Research Partnership was established in 2009 to enhance cetacean conservation and the delivery of non-lethal whale research to the International Whaling Commission (IWC). SORP partners include Australia, Argentina, Brazil, Chile, France, Italy, Mexico, New Zealand, South Africa and the United States. The Partnership research focus is on post-exploitation whale population structure, health and status; and changing atmosphere and oceans: Southern Ocean whales and their ecosystems.