Scientists mount cameras on sea lions to map Australia’s ocean floor

Australian scientists have shared the initial results of a study that equipped sea lions with cameras and sensors to help map the seafloor, while also helping conservation efforts for the endangered marine mammals.

The study, funded by the Australian government’s National Environmental Science Program and the Ecological Society of Australia, has been published in Frontiers in Marine Science.

It reveals maps of the sea bed and the animals’ habitat over different areas, and also valuable insights into the sea lions’ behaviour.

According to the Guardian, sea lions were hunted until the early 20th century, while fishing nets and pots have proved a more modern threat to their survival.

The result is that numbers of sea lions have declined by 60% in the past 40 years, leaving only about 10,000, mostly spread thinly across 80 breeding sites along Australia’s south and west coastline.

One of the challenges the study has sought to overcome is the difficulty of studying the seabed, which is traditionally time-consuming as it needs to be done from above by boat. Scientists believe that understanding the health of these marine habitats is vital to ensuring the species' survival. 

Enter the sea lions - so far, eight females from two seal colonies have filmed almost 90 hours of footage across more than 500km, helping scientists to map 5,000 sq km of habitat.

The adult sea lions selected for the study were first tranquilised and then equipped with cameras attached via a neoprene rubber patch the size of a credit card.

When the sea lions moult, the patch and camera will fall off naturally. Females were selected for the study as they regularly return to shore to feed their pups, allowing for the data on the cameras to be collected.

Interestingly, the study has also given new insights into sea lion behaviour, including that individual animals have different tastes – some seek out cod, others octopus or cuttlefish, while others 'dig out' prey by rolling over rocks with their noses and flippers, according to the researchers. 

Professor Simon Goldsworthy, who has overseen the research project, describes the captured footage as 'the best slow tv ever'

“Information has been so elusive, because they’re feeding at the bottom of the sea,” he told the Guardian. “Now we get this amazing, exquisite detail. They’re giving us a window into their world that we haven’t had before."