More than 5,000 kilometres of previously uncharted seabed in southern Australia has been mapped using footage captured by endangered sea lions. or signup to continue reading "They're already such a beautiful and charismatic animal, but then when you watch the video ..
. you get such an extra appreciation for the animal when you realise how hard they're out there working," PhD student Nathan Angelakis said. "They're constantly diving to the bottom to 90 metres, catching fish around the bottom and just completely exhausting themselves - and then they have to come back and nurse a pup," he said.
Mr Angelakis, a PhD student with The University of Adelaide and the South Australian Research and Development Institute, said the research was also fundamental in protecting an endangered species. Australian sea lions were historically hunted for their fur, and by over 60 per cent in four decades. Now, their biggest threat is gillnets - a near-invisible wall of netting that hangs vertically in the water.
After combing through - courtesy of their flippered employees - Mr Angelakis and other researchers identified six seabed habitats: macroalgae reef, macroalgae meadow, bare sand, sponge and sand, invertebrate reefs and invertebrate boulder. Ocean habitats are notoriously difficult and expensive to research and require certain conditions. "One of the main advantages is that [sea lions] cover large distances in short time frames," Mr Angelakis said.
"So they're a really good way of efficiently mapping sea bed." Eight female Australian sea lions from two South Australian colonies were rigged with small, lightweight cameras glued to their fur. But first, the sea lions had to be caught.
While sedated, they attach the cameras and tracking equipment, which is left on the animal for a single foraging trip - which can last between two to six days. "We deployed the instruments on adult females so we could recover the equipment a few days later when they returned to land to nurse their pups," Mr Angelakis said. The researchers then used the data to predict ocean habitats across the continental shelf of southern Australia.
Mr Angelakis said having the sea lions' perspective of their habitats and behaviours was significant. "Getting that data and footage from areas of the seabed that haven't been explored before, it's amazing to get this new information on areas that we have no idea about," he said. While looking through footage, the researchers witnessed some special sights.
"We had footage of a mother taking her pup to sea," the PhD student said. "That's the first direct evidence we have that Australian sea lion mothers pass on their foraging skills to their pups to help them in exploiting different habitat types or different prey." Mr Angelakis said there was also videos of encounters with sharks, schools of dolphins, stingrays, and other sea lions.
"With each deployment we do on an animal, we learn new things about their behaviour and about the ocean," he said. A limitation of the study, Mr Angelakis said, was that sea lions sometimes selectively choose their habitats. "They may not have swam over or foraged in particular habitat types, and then we didn't observe those habitats, and then they weren't included in the model," he said.
This latest research paper is just one chapter of what will make up Mr Angelakis's PhD. For instance, another chapter will focus on the foraging strategies of sea lions. The study was and was supported with funding from the Australian Government and The Ecological Society of Australia.
Journalist at The Examiner, Launceston, covering community, environmental stories and court stories. Contact me at annika.rhoades@austcommunitymedia.
com.au Journalist at The Examiner, Launceston, covering community, environmental stories and court stories. Contact me at annika.
[email protected] DAILY Today's top stories curated by our news team.
WEEKLY The latest news, results & expert analysis. WEEKLY Get the editor's insights: what's happening & why it matters. WEEKLY Love footy? We've got all the action covered.
DAILY DURING OLYMPICS Wake up to a tasty serving of overnight news and excitement from the 2024 Olympic Games in Paris. WEEKLY Every Sunday explore destinations, deals, tips & travel writing to transport you around Australia and the globe. WEEKLY Going out or staying in? Find out what's on.
WEEKDAYS Sharp. Close to the ground. Digging deep.
Your weekday morning newsletter on national affairs, politics and more. TWICE WEEKLY Your essential national news digest: all the big issues on Wednesday and great reading every Saturday. WEEKLY Get news, reviews and expert insights every Thursday from CarExpert, ACM's exclusive motoring partner.
TWICE WEEKLY Get real, Australia! Let the ACM network's editors and journalists bring you news and views from all over. AS IT HAPPENS Be the first to know when news breaks. DAILY Your digital replica of Today's Paper.
Ready to read from 5am! DAILY Test your skills with interactive crosswords, sudoku & trivia. Fresh daily! Advertisement Advertisement.
