In a world first, acoustic technology has been used to successfully find, track and study the biggest creature on Earth, the Antarctic blue whale.
Blue whales are very rarely seen in the Southern Ocean and yet by using this technology scientists on a seven-week voyage to the Southern Ocean were able to collect 57 photo identifications, 23 biopsy samples and attach satellite tags to two of these colossal whales.
Environment Minister Tony Burke said the researchers, working from small boats in freezing Antarctic conditions, were entertained and captivated by the remarkable behaviour of the blue whales they encountered.
Mr Burke said the achievements of this non-lethal research method clearly show it is not necessary to kill whales in order to study them.
“The Antarctic blue whale can grow to over 30 metres in length and weigh up to 180 tonnes, its tongue alone is heavier than an elephant and its heart is as big as a small car. Even the largest dinosaur was smaller than the blue whale,” Mr Burke said.
“The Antarctic blue whale barely escaped extinction during the industrial whaling era in the 1900’s when around 340,000 whales were slaughtered,” Mr Burke said.
“This research reinforces Australia’s commitment to non-lethal research of whales.”
The voyage was the inaugural Southern Ocean trip of the Antarctic Blue Whales Project, which aims to estimate the abundance, distribution and behaviour of this iconic species.
The 18-strong science team of acousticians, engineers, whale tagging experts and observers deployed passive acoustic sonobuoys west of the Ross Sea area to locate the blue whales.
Lead marine mammal acoustician, Dr Brian Miller, said Antarctic blues have a very deep and resonating song which can be picked up hundreds of kilometres across the Southern Ocean.
“The acousticians made 626 hours recordings in the sample area, with 26,545 calls of Antarctic blue whale analysed in real time. The researchers were then able to triangulate the position of the whales from their vocalisations and direct the ship to the target area,” Dr Miller said.
“A team in a small boat was then deployed to gather skin biopsies and photo identifications from the whales,” he said.
Whale tagger, Dr Virginia Andrews-Goff, said the researchers were able to deploy satellite tags on two blue whales.
“The tags transmitted never-before obtained data on rapid longitudinal movements during their summer feeding season and their foraging behaviour in relation to the edge of the Antarctic ice,” Dr Virginia Andrews-Goff said.
“This method of studying Antarctic blue whales has been so successful it will now become the blueprint for other whale researchers across the world.”
On the voyage the scientists made a total of 720 cetacean sightings, including humpback, minke, fin and bottle-nosed whales, as well as collecting environmental data and Antarctic krill samples.
The Antarctic Blue Whales Project is a flagship program of the international Southern Ocean Research Partnership involving ten countries – Argentina, Australia, Brazil, Chile, France, Germany, New Zealand, Norway, South Africa and the United States.
The results from this voyage will be shared with the International Whaling Commission to assist in the conservation and recovery of the Antarctic blue whale.
What an incredible privilege to get up close to these animals, you can't imagine how large they are. Words just cannot describe it, and everyone on that vessel when we first came up close to a blue whale let out a gasp.
Dr Jay Barlow, Science Co-ordinator
Overall, the mission has been tremendously successful. It exceeded all of my expectations. I think the most exciting achievement is just our having the ability now to find these blue whales in the really thin soup that is blue whales in the Southern Ocean right now. There used to be 200,000 blue whales in these waters and now there's something like one percent of that, it might be two percent, but it's really hard in the vast areas here to find them. Now we have this acoustic technology that allows us to do it with unprecedented speed and accuracy.
Dr Brian Miller, Lead Acoustician
My daily job involves deploying sonobuoys and managing a team of passive acoustics experts who are listening for whale sounds and guiding the ship to the whales, working with the ship's crew and additional observers to make sure that we have every chance possible to see the whales.
[Speaking into radio] Yes, we've detected blue whale calls.
So this is the first voyage of its kind. Our success rate has been very high. We've demonstrated these techniques, that listening for whales and heading towards them can enable us to sample and get to very rare Antarctic blue whales.
Paula Olsen, Lead Observer
Photo identification of blue whales involves taking photographs that allow us to recognise blue whales as individuals similar to taking a photograph of a human. With photo ID data, you can estimate population abundance, you can delineate stock structure between different population stocks of blue whales, you can also track movements on fine and large scales such as migration routes. These photographs we're collecting on this voyage will be contributed to a larger, southern hemisphere-wide whale catalogue.
Dave Donnelly, Coxswain
I guess one of the key things with this is to make sure that you're working within the parameters of your permitting, and also that you have a really good understanding of behaviour and being able to read whether or not you're having a negative impact on the animals. The Antarctic voyage has thrown out a lot of challenges to someone like myself, being my first time down to this region. Not only the climate and the conditions that you're faced with, but also these animals which I've never worked with before. They're extremely fast, they're quite large as everyone would know, and for what it's worth I prefer to work with them close to the ice edge where they seem to be more relaxed.
Dr Virginia Andrews-Goff, Whale Tagger
We have a very experienced coxswain who drives around the whales and has learnt whale behaviour for the last ten or so years so he generally predicts what the whales are doing and when he sees a moment to get close to the whales he will pick that moment to bring the boat in fairly quickly. Often the water is very rough so I'm bouncing about in the bowsprit trying to focus on a whale and where I need to deploy my tag. We'd like the tag to have the most opportunity to communicate with the ARGOS satellite system so the tag needs to be forward on the body and quite high on the body so it's out of the water as much as possible for the surfacings that the whale makes.
Once I placed a tag on the blue whale I was actually in a state of disbelief and shock. I didn't react at all, it was in slow motion and I turned around and I looked at my colleagues. I needed their confirmation that I'd actually tagged an Antarctic blue whale. Once that had happened I was grinning from ear to ear.
Since we placed the tag in the whale it's managed to travel north incredibly quickly, and then travel west. So it's travelled over 1000 kilometres since we tagged it. We have very little knowledge of the movements of Antarctic blue whales and in particular we are interested in the linkages between breeding and feeding grounds.
Dr Natalie Schmitt, Whale Geneticist
Well it's amazing what we can do with these samples, we can learn so much about these animals, and in a fairly non-intrusive way. So from each skin sample we collect from a blue whale we then extract DNA from that sample and through that DNA we can obtain genetic signatures for each individual and then we can track that individual - has that individual been sampled previously on this voyage? So we can look at movement within a season, and we can also match those genetic signatures to individuals that have been sampled on previous voyages between seasons on a broad scale.
Dr Brian Miller, Lead Acoustician
I couldn't imagine a better bunch of scientists or crew to work with. They’re all dedicated and hard-working, getting up every morning at 5:00 am, putting on their heavy clothes, going out into the sometimes driving snow, looking for whales, it's not an easy task.