Rare footage of whales captured in Antarctica. / Supplied by Antarctica NZ
Scientists have captured spectacular underwater footage of whales roaming beneath Antarctica's sea ice.
"I'm such an excited scientist right now," said University of Canterbury marine mammal expert Dr Regina Eisert, whose team filmed the minke whales during a recent expedition to the frozen continent.
One shot in the footage showed a minke whale floating gracefully through the frame.
Little was known about Antarctic minke whales, which could grow up to 10m long and weigh nine tonnes.
Eisert believed this may be the first time a minke whale has been filmed underwater, and in the sea ice, in the Ross Sea.
She was particularly excited as she didn't think anything had been captured on the prototype underwater camera designed by Antarctic film expert Anthony Powell of Antzworks.
"The plan was to film continuously across the icebreaker channel that is prepared for the re-supply vessel to cross McMurdo Sound," she said.
"The water's so clear, you can see right across the 50 to 80m lane and monitor all the whales that use the channel.
"Unfortunately, the system only recorded for just a few hours, due to teething problems for this new technology in the field.
"We had no idea that we had this footage until Anthony found it when checking the camera back in Christchurch."
Eisert's research programme focusses on fish-eating killer whales, but she also became interested in minke whales when she realised they were champions of ice navigation, beating even the killer whales in their ability to infiltrate deep into McMurdo Sound.
About 180,000 minke whales are in "Area V", the part of Southern Ocean that includes the Ross Sea region.
The species was likely to be an important part of the Ross Sea food web, but little was known about their precise role in the ecosystem.
Minke whales were also the only whales still hunted in the Southern Ocean, ostensibly for scientific purposes.
But there were other ways to study whales that cause no harm, such as photo-identification and dart biopsies.
When a minke swims by, Eisert and her team take a photo – and skin samples using a small dart.
"We can learn so much from a small tissue sample, such as their diet – we think they just eat krill, but do they eat small fish as well?
Scientists have captured spectacular underwater footage of minke whales roaming beneath Antarctica's sea ice. Photo / Supplied
"Also, DNA analysis can tell us whether Ross Sea minkes are separate from other minke whales on the Antarctic Peninsula or further north, or if they are all part of one larger population."
As filter feeders that primarily target krill, minke whales fed low in the food web and followed the retreating sea ice to find the richest feeding grounds, Eisert said .
"This means they're excellent indicators of 'ecosystem hotspots' – particularly productive areas.
"This information in turn feeds into environmental stewardship, in particular by supporting the objectives of the Ross Sea region Marine Protected Area (MPA)."
The Ross Sea region MPA came into effect in December.
It covered 1.55 million sq km, making it the world's largest marine protected area.
Ongoing research and monitoring was required to show that the MPA meets its objectives and to ensure the MPA's continued existence.
Eisert's team travelled to Scott Base with Antarctica New Zealand in January, and she hoped analysis of the samples and images they collected will begin a valuable data set for Ross Sea minke whale research.
