Scientists reveal methods to keep away from a shark assault – and their technique is surprisingly easy
Every year, around 80 unprovoked shark attacks are reported worldwide – including several that prove fatal.
But the days of avoiding the water could finally be a thing of the past, as scientists from Macquarie University have found a surprisingly simple method to avoid shark attacks.
Scientists say that attaching LED lights to you or your surfboard can create an ‘invisibility cloak’ which prevents sharks from attacking.
While their method has only been on tested on cardboard cutouts of seals so far, the experts say it could pave the way for new life-saving shark deterrents.
The system is based on the fact that while great white sharks are apex predators, their eyesight is poor.
This means that sharks decide whether or not to attack based almost entirely on their prey’s silhouette.
Just like the ‘dazzle camouflage’ used on battleships, the researchers found that bright lights actually made it harder for sharks to spot seal-shaped decoys.
Even though the sharks could still see the seal shape above them, they were no longer able to recognise it as potential prey.
Scientists have found that attaching bright lights to an object like a seal-shaped decoy or a surfboard actually reduced how often great white sharks attack. The researchers think this could be used to make life-saving shark deterrents for surfers
The researchers spent nearly 500 hours towing seal-shaped foam decoys through the shark-infested waters of Mossel Bay, South Africa to test shark deterrent strategies
Although great whites are the deadliest of all sharks, researchers don’t believe this is because they are naturally more interested in eating humans.
Rather, scientists believe that most great white attacks are accidental byproducts of the shark’s poor vision.
Lead author Dr Laura Ryan and her colleagues’ previous research shows that great whites are likely colour-blind and bad at making out details but excellent at spotting objects from afar.
However, sharks will attack almost anything with the right outline, including an unfortunate surfer on their board.
‘They are really good at detecting a silhouette,’ says Dr Ryan.
By understanding how a shark’s eyesight works, humans should be able to exploit that weakness to hide in plain sight.
The researchers spent nearly 500 hours towing seal-shaped foam decoys through the great white-infested waters of Mossel Bay, South Africa.
Each of the decoys was decorated with a different pattern of LED strips of various brightnesses.
Scientists found that attaching lights to a seal-shaped decoy significantly reduced how often great white sharks attacked
Great white sharks actually have poor eyesight, meaning they attack based on the outline of their prey rather than any fine details. Since surfers look like seals from below they are often accidentally hunted
While the plain control decoys were frequently attacked or chased by sharks, the researchers soon spotted that the lit-up seals were attacked far less often.
Bright lights were found to be the most effective with zero interactions with great whites occuring while the LEDs were set to maximum intensity.
Yet the researchers also found that this effect wasn’t simply because the sharks were being blinded or scared off by the lights.
A decoy fitted with flashing strobe lights was also sent out into the waters but this proved to be even less effective than continuous lighting at deterring sharks.
This suggests that the lights deter attacks by breaking up the decoy’s silhouette, which was still visible between the flashes.
Co-author Professor Nathan Hart says: ‘It’s like an invisibility cloak but with the exception that we are splitting the object, the visual silhouette, into smaller bits.
‘It’s a complex interaction with the shark’s behaviour. The lights have to be a certain pattern, a certain brightness.’
The researchers also found that decoys fitted with horizontal stripes were attacked less than those with vertical stripes, although both received less attention than the control.
Coating the bottom of the foam decoy with lights led to a dramatic reduction in interactions including following and breaching (illustrated right). When the lights were set to bright, interactions were reduced to zero
The study found that decoys fitted with LED stripes never had any interactions with great white sharks while some control decoys were attacked more than 12 times. Vertical stripes helped but were less effective than the horizontal placement
In their paper, published in Current Biology, they argue that this is because a pattern of vertical stripes still leaves some prey-like shapes.
Dr Ryan says: ‘When you have the lighting going along the body, you still have a long, narrow silhouette left over, which is going to be similar to what a seal produces.’
On the other hand, even four thin horizontal strips reduced the total interactions with sharks to zero.
Finding a way to protect surfers is absolutely vital as the number of recorded shark attacks rapidly increases around the world.
In 2023, over 40 per cent of attacks involved surfers – many of which were in the shark hotspots around the US and Australia.
Last year, California surfer Michael ‘Jared’ Trainor, 33, was attacked by a 16-foot-long great white shark, weighing over 1,000 pounds.
Mr Trainor was waiting for a wave when the shark struck from below, tossing him into the air before dragging him beneath the water.
Luckily, Mr Trainor was able to escape the shark and survived the attack but others have not been so lucky.
Michael ‘Jared’ Trainor (pictured), 33, was catching waves off a remote Ferndale beach in October 2022, when he was attacked by a great white shark from below. Luckily his leg was trapped by his board, preventing the shark from biting any deeper
Using motion tracking cameras the researchers found that horizontal stripes produced outlines which more most dissimilar from an unadorned seal shape. This may have meant that sharks were simply unable to recognise the decoy as a prey item
In 2022, British diving instructor Simon Nellist, 35, became the first person to be killed by a great white shark on a beach in Sydney in almost 60 years.
Likewise, a scuba diver named Manuel López was reportedly decapitated by a great white while diving near San Jose Beach in Tobari Bay on the western coast of Mexico.
The goal is now to take this discovery and create a technology that could help save human lives.
Understandably, South African authorities wouldn’t allow the team to test their ideas on surf-board-shaped decoys for fear of creating a danger to local surfers.
However, Dr Ryan and Professor Hart say there is no reason that the same technique shouldn’t work for surfers.
‘What we’re trying to do now is move from seal decoys into a surfboard prototype by embedding LEDs into the bottom of a surfboard,’ says Dr Ryan.
Further testing will be needed to see if the lights are as effective for stationary objects like a surfer waiting for a wave or against other dangerous sharks such as bull sharks.
However, the researchers remain hopeful that this breakthrough could one day avert deadly attacks to keep both surfers and sharks safe.
