Sydney, Australia - For many swimmers, there are few things more terrifying than the thought of being attacked by a shark. It's a primeval fear that many people just can't shake, though they are a 1,000 times more likely to die from skin cancer, 30 times more likely to drown in their own bath tub and 11 times more likely to be killed by a vending machine. In fact, the odds of being killed by a shark are one in 3,748,067, according to the Florida Museum of Natural History,.
But the odds are slightly more stacked against beachgoers in Western Australia. Following six fatalities in the past two years, the state now holds the unenviable reputation as the world's deadliest place for shark attacks.
In an effort to make the seas safer, the Western Australian Government trialed a controversial shark cull program from January to April that saw baited hooks attached to flotation devices placed at beaches around its state capital, Perth. Of the 172 sharks caught by these "drum lines", 50 were deemed dangerous - sharks measuring greater than 3m in length - and were subsequently killed. And while no human fatalities were recorded during the trial period, the programme sparked nationwide protests including a 6,000-strong demonstration in Perth against what conservationists described as a knee-jerk reaction targeting endangered species that play a key role in keeping the oceans clean by eating dead and sickly animals.
To its credit, the government is also investing $1.85m annually in research and development (R&D) grants for environmentally friendly shark-attack mitigation technologies. Among the recipients is "Shark Shield", a Perth-based company that makes braid-like chords that emit electromagnetic fields that have, to some extent, been proven to make sharks feel discomfort and swim away. Shark Shield has sold over 30,000 units to individuals and institutions - including the US and Australian navies and coast guards.
"With the steady climb in shark attacks around the world, we are seeing a lot of interesting new technology being introduced to protect humans without culling sharks," says Shark Shield managing director Lindsay Lyon.
Meanwhile, the newest and most interesting of these is an anti-shark wetsuit launched with great media fanfare last month by Shark Mitigation Systems. Based on research that found sharks see in black and white and use contrast (such as the silhouette of a scuba diver in a black wetsuit against the sun), it uses a "cryptic" blue and white pattern that theoretically makes it difficult for a shark to see the wearer. The wetsuit offerings also include one designed specifically for surfers with highly visible black and white bands inspired by the "warning" patterns of venomous sea snakes that make wearers appear totally unlike regular prey.
Burden of proof
A proper researcher would find all sorts of problems with the methodology.
Radiator, one of the companies licensed to manufacturer the wetsuits, is not offering wearers any guarantees. "When people ask us if they work, we say it works better than wearing a black wetsuit and looking like seals, the shark's favourite food," says Radiator proprietor Bob Lushey. "But there is simple logic behind it - and solid science."
Radiator's argument is backed by field tests that filmed the behaviour of sharks attracted to a "control" bait covered in an ordinary black wetsuit, alongside an identical bait covered in the cryptic- and warning-coloured wetsuits. The footage, which can be seen in the final minutes of this Youtube clip, shows a tiger shark and a great white shark savaging the control bait. Yet minutes later they appear not to see or be highly wary of the cryptic and warning bait.
But how much weight do these tests carry? Not much according to Andrew Fox, a marine biologist who runs great white shark cage-diving expeditions in South Australia.
"A proper researcher would find all sorts of problems with the methodology, starting with the fact that in those tests, the sharks changed from their natural predatory mode to a scavenging mode," he says. "Those clips make good eye candy. But long-term trials are required."
Charlie Huveneers, a senior lecturer in marine biology at South Australia's Flinders University who's carried out extensive tests on electric shark deterrents, adds that "there is sometimes a danger to making statements about the efficiency of a repellent based on anecdotal information or a limited amount of testing. It could lead to a false sense of security".
Experts interviewed for this story also pointed out that even if the new wetsuits work as intended, sharks use much more than eyesight to mark their prey.
The predators' powerful sense of smell is well known - genetically advanced olfactory nodes that allow them to detect blood in concentrations lower than 1 part in 10 billion. Then there's the "Ampullae of Lorenzini", a network of jelly-filled pores sharks have under their skin that allows them to detect the electromagnetic field emitted by muscle spasms and the heartbeats of living animal. Shark Shield claims they cleverly turn this hunting tool against its hosts, yet, like the wetsuit, they don't come with any kind of guarantees.
"The tests we did in South Africa were very promising to the point where we didn't observe one breach, " Huveneers said. "However, testing in South Australia did not find such strong results, with baits still being consumed as frequently regardless of whether the [device] was turned on or off."
Social media for sharks
Sharks also have an acute sense of hearing. Looking at ways to interfere with sharks' ability to hear humans in the water is the subject of a new government-funded study headed by Dr Christine Erbe of Curtin University's Centre for Marine Science and Technology in Perth.
"If we can successfully identify a difference in behaviour, masking sounds could be broadcast into the water by speakers along beaches or perhaps by the development of small, personal maskers that could be used by swimmers and other water users," Erbe said. "We believe this approach is minimally invasive … and in contrast to deterrence devices, there is no risk of the sharks becoming accustomed to a stimulus."
When and if they are ever developed, sound-based shark-attack deterrents will add to a genre of high-tech solutions that promise to be more effective than anything currently sold over the counter.
Any technology that stops us from killing sharks is well worth having a look at.
One such idea that's closer to become a reality is the Clever Bouy system earmarked for trials at Sydney's famous Bondi Beach later this year. Developed by Shark Mitigation System in conjunction with Google and telecom provider Optus, the bright yellow buoy will use sonar to detect shark-sized objects in the water and relay a signal to lifeguards in the event a detection is made.
Then there's social media, which can - and already is - helping humans coexist with sharks. The Western Australian Fisheries Department has attached transmitters to 320 large sharks that discharge tweets whenever the host moves within 500m to the shore. The tweets, posted on the Twitter account of Surf Life Saving Western Australia, inform beachgoers of the exact location, type and size of the shark.
Education can also play a crucial role.
"Teaching beachgoers simple things like safety in numbers, not to swim in murky waters, near deep channels or at dusk or dawn when sharks are feeding actively is massively important," says marine biologist Andrew Fox. "I also think we need more studies on shark migration to find out when and where they move into certain areas and linking them to sightings. That is where the money should be spent."
But at the end of the day, all of these shark-attack mitigation strategies and devices are nothing more than deterrents.
"Any technology that stops us from killing sharks is well worth having a look at," says Lindsay Lyon of Shark Shield. "But these things are like seat belts or an air bag. They work well, but if you get hit by a Mack truck, you're dead."
Source: Al Jazeera