On-screen text: In the Southern Ocean, scientists are finding krill by following the blue whales that eat them.
ROB KING: It’s fascinating to be on a voyage where we're targeting areas to research by focusing in on blue whales that we're hearing from hundreds of kilometres across the ocean.
On-screen text: For the first time, the RV Investigator’s echosounders are being used to ‘see’ giant krill swarms underwater.
JOSH LAWRENCE: So the animation is showing us a three-dimensional representation a large krill swarm we passed over earlier in the voyage. The swarm was about 400 metres long by about 200 metres across and it kind of came up in this multi-level swarm that was a total depth range of about 100 metres, but with the three-dimensional view you can see that it’s all connected and it’s all one enormous swarm.
On-screen text: With a volume of a million cubic metres, this single swarm contains hundreds of millions of Antarctic krill.
ROB KING: What sort of krill is a blue whale after? Because krill isn’t just an individual. Krill is a super organism.
JOSH LAWRENCE: It might tell us something about the preferences that the whales have for the different three-dimensional structures. Again, that’s something you wouldn’t really be able to do without that three-dimensional information.
On-screen text: Each swarm recorded by the echosounders is also sampled for its krill.
ROB KING: There’s a whole bunch of female krill here that are ready to lay eggs. There’s also a lot of developing juvenile krill that are maturing. But what’s really interesting is that those krill are mainly females so it appears there’s a strong gender imbalance in this area. It’s not preventing them producing fertilised eggs. All of the females that have spawned here in the lab have produced fertilised eggs that have gone on to produce embryos, no trouble at all. So the system is working but we're not sure where the males are, so we're going to be looking for those as the cruise continues.