Minke whales swimming near Davis, Antarctica. The whales out in the open are much easier to count than the ones that swim under the pack ice.
Credit: Frederique Olivier/Australian Antarctic Division
SYDNEY: A new technique for surveying minke whales in the Antarctic will determine if their population is truly in decline, said a team of Australian researchers.
Over the past 20 years, ship-based research has found a decline in minke whales (Balaenoptera acutorostrata). But since the whales also spend time under the pack ice, where they could not be seen, it was unknown whether the population decline was real or if the whale populations had shifted under the pack ice, said researchers from the Australian Marine Mammal Centre, part of the Australian Antarctic Division, and CSIRO Mathematical and Information Sciences.
For the first time, researchers took to the air over Antarctica to find out. Natalie Kelly, a statistician from CSIRO, tested the aerial survey technique in 2007 to see if it worked. Initially, spotting whales among the pack ice was tricky, she said. "It was very hard to begin with. When you're 230 m above the pack ice there's little sense of scale. You see something below and ask yourself 'is that a whale or a penguin?' But once you get your eye in it's easy."
A year later in December 2008, Kelly and the team flew a total of 8,238 km collecting data. They used video, infrared video and digital photography, along with observations from four researchers on board the aircraft. This information is currently being analysed to produce a more accurate estimate of the Antarctic minke whale population size.
Preliminary findings suggest the aerial surveys are an effective way of counting whales. "The method works. We recorded nearly 500 whale sightings over the 41 hours we were in the air," said Kelly. Some of these sightings were of different whale species. The team will present their research at the next International Whaling Committee meeting in June.
Aerial surveys are yet another way we can learn about whales without killing them. Non-lethal techniques are "the way forward for whale research in the future," said Peter Garrett, the Australian Environment Minister.
Before these methods were developed, whales were studied aboard a whaling vessel. Biologists dissected animals that the whalers caught to study their physiology and examined their stomach contents to find out what they ate.
Some of the researchers involved are taking part in the first workshop of the Southern Ocean Research Partnership, which began this morning in Sydney. Garrett hopes that the workshop will lead to many more advances in the field of non-lethal whale research. "This is science that will make the world sit up and take notice."
Aerial survey of minke whales
Hope this technique isn't used to hunt the whales.