Innovative Approach to Minimize Shark Encounters: Introducing Emitters to Limit Shark-Related Incidents
In the cold, azure seas adjacent to South Africa's Mossel Bay, researchers have been experimenting with an unusual strategy to lessen shark attacks: lights. spearheaded by Australian neurobiologist Dr. Laura Ryan and her companion, Professor Nathan Hart, the results were recently exposed after numerous years of investigations. While examining the great white's visual capabilities, Ryan – a devoted surfer herself – started to ponder if their reliance on vision to recognize (probable) prey could be the secret to making swimmers and surfers less alluring to these supreme predators.
“There was a surge in shark attacks, and as a truly enthusiastic surfer, I was investing a considerable amount of time pondering sharks’ eyesight,” she recounts. The team concentrated on the theory that some sharks might confuse a human's silhouette with that of a seal, a staple food source. To determine if lights could disrupt these silhouettes and make humans less appealing targets, the researchers undertook a six-year investigation in one of the few areas worldwide with a sufficient concentration of great whites to carry out meaningful experiments.
South Africa.
“The reason we traveled to South Africa is that there aren’t many locations globally where you'd have the concentration of sharks required,” she said. Indeed, these waters are renowned as a haunt for these apex predators, making it one of the few sites globally where researchers can dependably observe and research them. The relatively constant presence of these sharks enabled the researchers to design and execute this type of controlled experiment, which entailed pulling seal-shaped decoys equipped with lights beneath the boat's underside. The lights were intended to dismantle the decoy's silhouette, making it more difficult for sharks to recognize it as prey against the bright sunlight filtering through the water.
The findings were astonishing. When the decoys remained in their fundamental form, they were frequently assaulted from below by great whites. However, as the decoys grew brighter, sharks became less likely to approach or assault them. Nevertheless, not all light setups were successful. Flashing lights, for example, had little impact. Additionally, the team attempted longitudinal stripes of LED lights, but these were less effective. “When you have the lighting running along the body, you still have a long, slender silhouette remaining, which is comparable to what a seal produces,” says Ryan. However, when the researchers placed LED lights in striped patterns across the decoys, perpendicular to the movement's direction, the results demonstrated that the sharks could detect the decoys but ceased attacking them. This unique design fragmented the decoy's shape into smaller visual components, baffling the predators. Professor Hart described the effect as a “invisibility cloak,” though it only works by splitting the object's silhouette into smaller, less discernible fragments.
The repercussions of this research are substantial. Each time the striped light pattern was tested, shark attacks on the decoy dwindled to zero. “It’s a complicated interaction with the shark’s behavior. The lights have to be a certain pattern, a certain brightness,” Hart explains. While coating the entire underside of a surfboard with LEDs would be both costly and impractical for real-world applications, the study provides a hint into how non-lethal shark deterrents could be formulated, especially for surfers and watercraft users.
Yet, can this breakthrough immediately herald safer conditions for surfers? Not just yet. While the findings with seal-shaped decoys are encouraging, the research didn’t evaluate lights on surfboard prototypes. South African authorities were understandably hesitant to employ surfboard-shaped decoys, fearing they might entice sharks nearer to real surfers. Nonetheless, the researchers believe the same principles could apply.
Dr. Ryan and her team are now working on incorporating LED lights directly into surfboards. The subsequent stage of research will involve testing whether the lights remain effective when a surfboard is stationary in the water – such as when a surfer waits for a wave. The team is also considering expanding the system's application to other potentially dangerous shark species, such as bull sharks and tiger sharks. However, while great whites are well-known for relying heavily on visual cues to hunt seals, other species might not rely on sight in the same way. “We don’t know if it will be as effective on them because we’re not sure if they rely on visual cues as much as white sharks,” Ryan concludes.
- Dr. Laura Ryan, a great white shark researcher and surfer, hypothesized that lights could make humans less attractive to sharks due to disrupting their visual recognition of prey.
- In South Africa, where great white sharks are common, the team tested their theory by pulling seal-shaped decoys with lights beneath a boat, finding that brighter lights decreased shark attacks.
- Flashing lights and longitudinal stripes of LED lights were less effective, but perpendicular stripes baffled the sharks, reducing attacks to zero in trials.
- The research suggests that non-lethal shark deterrents for surfers and watercraft users could be developed based on this finding, though testing surfboard prototypes is still needed.
- While the study focused on great white sharks, the team plans to explore the effectiveness of LED lights on other dangerous shark species like bull sharks and tiger sharks.
