Antarctic Blue Whale and Krill Voyage 2019
Blue whales and krill
Antarctic blue whales are not only the biggest animals on the planet, they’re the largest that have ever existed. Adults reach more than 30 metres in length, 100 tonnes in weight, and live for more than 80 years. The blue whale is also arguably one of the noisiest animals, regularly making intense low-frequency calls that travel underwater for hundreds of kilometres.
Hunted to near extinction until the 1970s, the population of Antarctic blue whales was reduced to a few hundred individuals. Today, while their population is recovering, blue whales remain rare and endangered. Where they migrate to breed is currently unknown.
Antarctic blue whales almost exclusively eat krill, and in vast amounts. In one day, an adult blue whale can eat up to 4 million krill, more than three tonnes. To do this, they must feed in areas where they can find high krill concentrations. They spend summer in the krill-rich waters around the Antarctic ice edge. More study needs to be done to understand how these enormous krill swarms are distributed in the Southern Ocean.
Antarctic krill are one of the most abundant and successful animal species on Earth. Scientists estimate there are about 500 million tonnes of Antarctic krill in the Southern Ocean. The biomass of this one species may be the largest of any multi-cellular animal species on the planet.
Antarctic Blue Whale and Krill Voyage 2019
Do krill swarms affect the distribution and behaviour of whales? How does the mix of predators, prey and their poo affect productivity in the Southern Ocean?
These are just some of the questions a team of 28 krill, whale and biogeochemistry experts wanted to answer during an ambitious 49 day voyage aboard the CSIRO research vessel Investigator to East Antarctica and the Ross Sea region.
This research was part of the Australian Antarctic Program, supported by a grant of sea time on RV Investigator from the CSIRO Marine National Facility.
The voyage was called ENRICH, standing for ‘Euphausids and Nutrient Recycling In Cetacean Hotspots’ (note: euphausids are krill, cetaceans are whales).
Scientists got an intimate glimpse into the daily lives of both blue whales and krill, using a range of technologies like underwater listening devices (sonobuoys), multibeam echosounders, and even drones to photograph whales and collect their blow and faeces.
The voyage departed Hobart on 19 January 2019 and returned on 6 March 2019.