The Earth’s seafloor is one of the least explored areas of our planet. Despite significant technological advances, mapping these vast underwater landscapes remains a major challenge, mainly due to the high cost and complexity involved.

Conventional methods often rely on remotely operated vehicles (ROVs), which are effective but are limited by weather conditions and ocean depths.

A team of researchers in Australia has launched an exciting development and presented an innovative solution to these obstacles. They use the unique camera-carrying ability of the endangered Australian sea lions to offer new insights into the enigmatic habitats of the seabed.

By exploiting the natural behavior of these animals, scientists can gain new perspectives on underwater ecosystems that were previously inaccessible to them.

Head behind the initiative

Nathan Angelakis, a PhD student at the University of Adelaide and the South Australian Research and Development Institute (SARDI), is making significant advances in marine research.

His team’s latest publication in Frontiers of marine science illustrates how collaboration with marine mammals can provide us with valuable insights into ocean research.

“Using video and motion data from a benthic predator is a really effective way to map different benthic habitats across large areas of the seafloor,” explained Angelakis.

“These data are useful both for mapping critical habitats for an endangered species such as the Australian sea lion and more generally for mapping unexplored areas of the seafloor.”

Mapping the seabed is difficult

The seabed is an important hub of biodiversity, supporting a wide variety of marine life and contributing to the overall biodiversity of our entire planet.

However, our actual knowledge and understanding of these unique habitats is still far from complete, mainly due to the challenges associated with their research.

It is often said that we know more about the surface of the Moon and Mars than the ocean floor. This may sound surprising, but it is 100% true!

This disappointing fact reflects the reality of our current deep-sea exploration capabilities and the challenges that deep-sea exploration entails.

Conventional methods for mapping the seafloor, such as remotely operated vehicles (ROVs), are effective but are often costly and face significant difficulties in the extreme conditions of the deep sea.

Sea lions and seabeds

To overcome these obstacles, Angelakis and his team have turned their attention to the Australian sea lion (Neophoca cinerea), an endangered species found along the south and west coasts of Australia.

By equipping nimble sea lions with lightweight cameras and tracking devices, they were able to collect important data about the seafloor and marine habitats along the entire continental shelf, revealing previously hidden regions of the ocean floor.

The study observed eight adult female Australian sea lions with cameras and GPS tracking devices attached that weighed less than 1% of their body weight.

“We deployed the instruments on adult females so that we could collect the equipment a few days later when they returned to land to nurse their young,” Angelakis explained.

“We used satellite-based GPS loggers on the sea lions so we could track their position in real time and know when they had returned to the colony.”

Data goldmine from sea lions roaming the seabed

Within two to three days, these marine scientists recorded 89 hours of footage – a goldmine for the researchers.

They covered a range of benthic habitats encountered during their dives, including, to name a few, macroalgal reefs, invertebrate boulder fields, and bare sand flats.

This diversity of environments provided a wealth of data and enabled researchers to map important habitats on the continental shelf.

“The sea lions from both sites covered fairly large areas around the colonies. In our calculations, we kept the area in which we predicted habitats small to maximize the accuracy of our predictions,” Angelakis enthused.

“This allowed us to model benthic habitats on more than 5,000 square kilometers of the continental shelf.”

Mapping the continental shelf

A breakthrough in this research is the ability to predict large habitat areas across the entire continental shelf of southern Australia.

The team used machine learning models that incorporated decades of oceanographic and ecological data, including temperature trends, ocean currents and nutrient levels.

Using this approach, the team was able to model benthic habitats over an area of ​​more than 5,000 square kilometers (1,930 square miles) of the continental shelf.

Protecting Australian sea lions ((Neophoca cinerea)

In addition to revealing previously unexplored benthic habitats, the study also provided important information about the endangered Australian sea lion. Over the past four decades, its population has declined by more than 60%, making this study invaluable to conservation efforts.

Australian sea lions are one of the rarest and most endangered sea lion species. They are easily recognized by their distinctive appearance. Males have a rich dark brown coat, while females and juveniles have a lighter, creamy gray coat.

These medium-sized marine mammals vary considerably in size: males reach a length of up to 2.44 metres and weigh around 300 kilograms, while females are generally around 1.83 metres tall and weigh around 100 kilograms.

What sets Australian sea lions apart is their unique breeding cycle, which occurs every 17 to 18 months, as opposed to the annual cycles of most other sea lion species. In addition, these highly social animals are often seen in groups, exhibiting playful behaviors in and out of the water.

Sea lions, seabed and future research

The inclusion of Australian sea lions in seafloor mapping represents a major breakthrough in marine research.

Using animal-based cameras to map seafloor habitats not only provides cost-effective solutions, but also extends our reach to areas inaccessible with conventional equipment.

As Angelakis and his team have shown, collaboration with animals in scientific research can lead to discoveries that would otherwise remain hidden.

By looking at the oceans through the eyes of a predator, we gain a new appreciation for the creatures that inhabit them and deepen our understanding of the marine environment.

As this study shows, sometimes the best way to unravel the unknown is to let nature take the lead.

The full study was published in the journal Frontiers of marine science.

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