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Technology gives new insights into Antarctic blue whales and krill

Drone water sampling iceberg. Photo credit Marine National Facility

The drone skills of a Murdoch scientist have helped to shed new light on the complex relationship between Antarctic blue whales and krill, and their roles in the productivity of the Southern Ocean.

Dr Joshua Smith, a whale researcher based at Murdoch University’s Harry Butler Institute, was the Unmanned Aerial Vehicle team leader aboard the CSIRO research vessel RV Investigator for a recent Australian Antarctic Program voyage.

Covering 200,000 square kilometres over seven weeks, the expedition was the first and largest multidisciplinary trip into Antarctic waters to study the relationship between some of the smallest animals, krill, and their biggest predator, the Antarctic blue whale.

Drone missions

Drones were used in more than 130 missions across a range of scientific applications, including the first size measurements and ‘blow’ sampling of blue whales in the Southern Ocean and a new method for trace metal surface water sampling.

Dr Smith said the trip was the first step to a better understanding of the recovery of the population from near extinction due to commercial whaling.

“Through the use of drones, we were able to determine the size and distribution of krill aggregations that blue whales are feeding on through krill trawling and we could observe the behaviour of whales while they were feeding,” Dr Smith said.

“This was a very exciting voyage that has produced rare Antarctic blue whale behaviour footage, the first non-invasive size measurements of the whales and an assessment of their health.”

Voyage Chief Scientist Dr Mike Double said the trip was an ambitious undertaking in an often hostile environment, and achievements have exceeded all expectations.

Over 300 hours of search effort led to 36 encounters with blue whales and individually identifying 25. One was a whale which had previously been sighted on an expedition six years ago.

Krill swarms revealed

For the first time on an Australian research vessel, echo sounders were used to construct three-dimensional pictures of giant krill swarms. Several swarms extended over one kilometre in length and hundreds of metres across, containing many millions of krill.

The voyage’s multidisciplinary research will contribute to the improvement of ecosystem-based management of the Antarctic krill fishery and the conservation of endangered species such as Antarctic blue whales.

Dr Smith is a research fellow in the Aquatic Megafauna Research Unit of the Harry Butler Institute. 

This research was supported by a grant of sea time on RV Investigator from the CSIRO Marine National Facility.

Photo credit: Marine National Facility

Posted on:

11 Mar 2019

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