“CAUTION,” reads the bright yellow sign firmly planted in the sand. “DRONE ACTIVITY IN PROGRESS.”
People gather around the sign, eyes darting between it and the people standing near it in matching shirts to solidify that they are a team. The chatter starts to get louder as people loudly ask why they are there, what they see, what is happening. The drone pilot ignores them, busy. Concentrating. Instead, their team asks bystanders to please stand back and not shout questions to the drone pilot – they are working. The person who is laser-focused on to the remote controller monitor in their hands isn’t filming the next viral Instagram Reel or TikTok video… they are looking for sharks.
Unmanned aerial vehicles, often known as drones, are an emerging surveillance technology that provides aerial surveillance of coastal waters and real-time vision of the area. More and more beaches are now implementing the use of drones to keep ocean-goers safe from not only sharks, but other possible dangers. Thanks to the technology, it seems as if we are seeing sharks more than ever before as drone operators from around the world upload their footage onto various social media platforms. While these videos show that these predators tend to ignore us (unless they are being chased or harassed), there are hundreds of hours of footage that you don’t see online that are being used to inform authorities’ decisions on beach management.
“[Drone] technology has really revolutionized and given us a completely different view of sharks,” Chris Lowe, a professor of marine biology and director of the Shark Lab at California State University, Long Beach, told The Verge. He went on to explain that before drones, scientists had to rely on planes and helicopters to perform aerial shark surveys. It was pricey, and clearly something that couldn’t be done every day. Enter a much cheaper alternative, the drone. Video footage from drones can be and has been used to quantify shark morphology and behaviors in shallow marine environments, and a new study has done exactly that… with a twist.
The movement patterns and behaviour of white sharks in nearshore waters is mostly predictable under normal conditions until you add stranded whale carcasses into the equation. Numerous whale populations are bouncing back around the world thanks to protective measures put in place, however, that means the number of whale carcass strandings has been increasing on remote and popular beaches. Led by scientist James P. Tucker of the National Marine Science Centre at Southern Cross University in Australia, a team set out to see how whale carcasses influence the numbers and behavior of potentially dangerous sharks in the vicinity of strandings. White sharks (Carcharodon carcharias) are present in varying abundances year-round here, and there are multiple records of them scavenging floating whale carcasses. Also known as ‘white pointer’ in Australia, they are the largest predatory fish on Earth. Found in cool, coastal waters around the world, they are an elusive marine top predator. Thankfully, since drones aren’t as expensive as traditional aerial surveys, the researchers were able to easily observed great whites along the coast of New South Wales (NSW).
There are not only great whites off the coast of NSW. Some whale species, such as Bryde’s whales (Balaenoptera brydei), are permanent residents of these waters, while other species, such as humpback whales (Megaptera novaeangliae), migrate annually. The researchers were able to collect drone-based video footage of white sharks at four separate whale carcass stranding events, which included two humpback whales, a fin whale (Balaenoptera physalus), and a sperm whale (Physeter macrocephalus); they also compared their findings to that of another dataset which collected similar drone-based data on white sharks at nearby beaches without whale carcasses from September 2016 to October 2018. “By comparing these two datasets, [we were able] to test the hypotheses about white shark behaviour changing near beach-stranded whale carcasses,” the authors explained.
After analyzing all of the footage, the team found that white shark behaviour was significantly altered by the presence of a stranded whale carcass. Differences in speed, length, straightness and sinuosity of white shark movements were observed. “These differences are relevant for management of shark risk on beaches because they indicate increased shark interest in locations close to stranded carcasses and should therefore be considered when developing whale stranding management plans and deciding when it is appropriate to enforce beach closures,” the authors said.
The message is clear: if there’s a whale carcass in the area, best to stay out of the water. Instead, maybe scout the carcass from a safe distance and/or location and see if you can spot any sharks feasting away! Perhaps get your own drone and add to the many videos we are now seeing online of sharks… well, being sharks. Drones are not only unveiling the shadowy parts of a shark’s every day life, but they are also shedding light on a new side of these predators. “The bottom line is there’s no doubt that drones have given people a different perspective [on sharks] because they get to see sharks around people and see that the sharks aren’t attacking,” Lowe concludes.