Scientists equip Australian sea lions with cameras to explore previously uncharted oceans

What lies beneath the ocean floor is often a mystery. In Australia, many underwater areas are uncharted, and researchers know very little about them. Now, scientists are working to change that by using sea lions as videographers.

Using video footage captured by sea lions, researchers identified six hotspots covering 5,000 square kilometers of ocean in southern Australia. This data would not only help provide valuable information to protect endangered species but could also be used to monitor other interesting marine species.

The world’s coastlines are underexplored, and the knowledge we have is scant. Using underwater vehicles to study the ocean floor is expensive, requires certain weather conditions, and is difficult in deep, remote and offshore areas.

To avoid these problems, Australian researchers have now recruited endangered sea lions (Neophoca cinerea) to take cameras. The resulting videos allowed researchers to identify previously unmapped areas used by sea lions on the continental shelf. They published their results at Frontiers in Marine Science.

“Using animal-driven videos and movement data from benthic predators is a really effective way to map different environments with different types of seabeds. ,” said first author Nathan Angelakis, Ph.D. student with The University of Adelaide and the South Australian Research and Development Institute (Aquatic Sciences).

“This data is useful for mapping important areas for endangered species such as the Australian sea lion, and more broadly, for mapping unexpected areas that may under the sea.”

Following the sea lions

For this project, eight large Australian lionesses from the Olive Island and Seal Bay colonies were fitted with small and lightweight cameras. Cameras and tracking devices were attached to small pieces of neoprene that were attached to the fur of the sea lions.

In general, the filming and tracking equipment weighed less than 1% of the sea lions’ body weight to prevent drag effects and allow the animals to move freely. The recordings were made over two to three days.

“We put the equipment in the older females so that we could get the equipment a few days later when they came back down to nurse their young,” Angelakis explained.

“We used satellite-linked GPS loggers on the sea lions, which means we can track their position in real time and know when they have returned to the colony.”

Predicting ocean locations

From the videos of the animals—89 hours of recording in total—the researchers identified six benthic habitats: macroalgae reef, macroalgae meadow, bare sand, sponge/sand, bare reef spine and spineless stones.

The researchers then used machine learning techniques to predict major habitats across Australia’s southern continental shelf. To do so, they included marine and environmental factors that may have influenced the shape and distribution of these habitats. The ocean data included in these models was based on 21 years of observations and measurements.

“Sea lions from both areas covered very wide areas around the colonies. In our calculations, we kept our predicted habitat very small. increasing the accuracy of our predictions,” Angelakis said. “This allowed us to model benthic environments across more than 5,000 square kilometers of the continental shelf.”

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As seen by sea lions

The areas the sea lions painted were more diverse than other mapped areas in South Australia. This may be due to differences in ocean/environmental conditions, as well as sea lions not using or traveling in certain areas or preferring some over others. It is possible that other ecosystems were missed, the researchers said.

However, this study makes a significant contribution to the knowledge of these marine areas and provides important information on an endangered species, whose population has declined by more than 60% in the last 40 years. . In addition, it can also be used to monitor and evaluate other interesting aquatic species seen in the video.

Surveying these habitats with animal-guided video provides an efficient and cost-effective method for future mapping efforts, the researchers said. Surveying oceans from a predator’s perspective, rather than following a traditional approach, can improve environmental scientists’ understanding and produce more detailed maps of the ocean floor.