The image of the great white shark attacking a surfer has terrified swimmers for decades. This image, which causes a lot of harm to sharks in general throughout the world, nevertheless remains a threat hovering over surfers on certain beaches.
In previous studies, researchers have found that great white sharks, the main culprits of coastal attacks, are likely colorblind and have low visual acuityvisual acuity. They would compensate for this by their great ability to spot silhouettes, which does not work in favor of surfers. Indeed, these sharks would not have the ability to differentiate the silhouette of a surfboard or a human in the water from that of a seal.
While many solutions have been tried to reduce attacks, such as bracelets with sound repellents, few have really proven their effectiveness. However, new research from Australia could change that.
A simple technique…
Macquarie University researchers recently published a study in the journal Current Biology showing that lightslights LEDLED placed under the boards altered the silhouette of the surfers, which could mislead these predators.
Inspired by nature, the researchers had this idea by observing a fish which knows how to escape predators by erasing its silhouette thanks to luminous spots lightening its belly. Mimicking this phenomenon, they tested various configurations of LED lights on seal-shaped lures, towed in Mossel Bay, South Africa, a place popular with great white sharks.
…but effective against great white sharks
And the results are promising: lures equipped with light strips attracted far fewer sharks than those without LEDs. “ It’s a bit like an invisibility cloak, except that we cut the silhouette into smaller pieces, explains Professor Hart, co-author of the study. This is a complex interaction with shark behavior. The lights must have a certain shape and a certain brightnessbrightness. » The researchers found that lights placed horizontally on the decoys were the most effective deterrent.
New tests will be necessary to verify the effectiveness of this method with other species of sharks, explain the researchers, particularly with tiger sharks or bull sharks. This technology could even be extended to kayaks, to protect more users at sea.
