Blue whale

Blue whales are the largest animals ever known to have lived on Earth.

Antarctic blue whale voyage

Video transcript

Dr Virginia Andrews-Goff, Whale Tagger

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 1,000 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 5:00am, putting on their heavy clothes, going out into the sometimes driving snow, looking for whales, it’s not an easy task.

[end transcript]

Scientific name: Balaenoptera musculus

The biggest blue whale ever weighed was nearly 200 tonnes and over 30 metres in length.

Both the Antarctic blue whale and pygmy blue whale have grey skin with mottled patterns. The patterns are different for each individual. When submerged, the blue whale appears to be a luminous pale blue or aqua.

Graphic comparing adult blue whale with length of three standard buses — Antarctic blue whales are the largest animal on Earth Photo: AAD

Distribution and abundance

Distribution: Blue whales, along with minke whales, venture further into the sea ice than other rorquals (such as the humpback and sei whales), and have been seen near 78°S in the Ross Sea. Non-lethal science using mark-recapture methods and acoustic tracking is being undertaken to determine the distribution and abundance of blue whales following the ban on commercial exploitation imposed by the International Whaling Commission in 1964.

Pygmy blue whales are never found south of 50°S, and feed off the southern Australian coast in summer. They grow to ‘only’ about 25 m.

Threats: Southern Hemisphere ‘true’ blue whales were reduced from around 225,000 individuals pre-exploitation to probably less than 2,000 now. In just one area – South Georgia – 30,000 blue whales were killed in the 1930–31 season alone.

Conservation status: endangered

Breeding

The breeding grounds of Southern Hemisphere blue whales are still unknown but are thought to lie somewhere in the deep oceanic waters of the tropical South Pacific, Atlantic and Indian Oceans.

A new born blue whale calf weighs 2.5 tonnes and can, in the latter stages of suckling, put on 100 kg a day.

Blue whales live for 80 to 90 years or longer.

Diet and feeding

A blue whale gulps up to 50 tonnes of water and krill in one feeding mouthful, but swallows only the krill.

'True’ blue whales are one of the fussiest eaters in the Antarctic, usually eating only Antarctic krill.

Whale song

Blue whales off Sri Lanka have a song which consists of only 4 long, low notes.

Low frequency moans of blue whales, some of them lower than human hearing, can theoretically travel several thousand kilometres, and at close range are as loud as a jumbo jet taking off.

Antarctic blue whale D-calls

Blue whale D-calls recorded from a sonobuoy deployed in the northern Ross Sea and sped up 4× to raise the pitch to be audible to people. D-calls are thought to be ‘social’ calls made by male and female whales on feeding grounds. D-calls are highly variable across individual whales and across seasons and years.

Credit: Brian Miller

Antarctic blue whale FM-calls

Blue whale FM (frequency modulated) calls recorded from a sonobuoy deployed in the northern Ross Sea in 2015. FM calls seem to be associated with animals in groups and may be shorter range, social or foraging sounds.

Credit: Brian Miller

Antarctic blue whale Z-calls

Recorded on an Antarctic Division moored acoustic recorder on the resupply route to Casey Station in 2014. The sound is sped-up 8× to raise the pitch. Z calls can be heard from long distances and seem to be produced by individuals, possibly for longer range communication.

Credit: Brian Miller