Sharks. Otherwise known as Perth’s own boogeyman (or boogeyfish). They’ve sparked a lot of fear in recent times, with the Barnett government even going so far as to legislate a period of culling through ‘bait lining’ following attacks off WA’s coastline.
Researchers from UWA may have found an alternative to this bloody tactic of keeping Aussie swimmers safe. Tested over 2014 in South Africa’s Mossel Bay, ‘Shark ShieldTM’ is being called the most effective shark deterrent device on the market yet. According to the Shark Shield website, it is “trusted by professional adventurers around the world, including navies, military and police divers, and is mandated safety equipment in many industries”.
There is certainly a demand for the technology. Comparative statistics – like the fact you’re more likely to be killed by a falling vending machine or a coconut than a shark – do little to curb public paranoia. Perhaps it’s due to Hollywood’s fascination with these mostly seal-eating ‘monsters’ that we find ourselves so fearful. Films like Jaws have a lot to answer for – as will no doubt the upcoming Blake Lively feature The Shallows.
So what does the existing shark deterrent product range look like? Currently on the market is the liquid solution ‘Anti-Shark 100’, which works as a ‘mace’ for sharks. With the bottle itself labelled ‘Dead Shark Juice’, it is made from putrefied shark tissue, which acts as a warning signal to other predators nearby. Magnetic wristbands are another option, with cheaper ones selling for around $35. Pulsing out magnetic waves, they are said to disrupt a shark’s sensitive electroreceptors. For each of these products there is no guarantee the device will work 100% of the time.
The Shark ShieldTM device is unique in that it uses submerged electrodes to provide a three-dimensional electric field. Overstimulating the shark’s sensitive electroreceptive system, the device effectively causes ‘snout spasms’- prompting the shark to scarper (unharmed) from the emitting range to some other area of sea (possibly near that diver who didn’t invest in Shark ShieldTM). Devices can be strapped to ankle, board or kayak, with minimal drag for the user.
Final test results of a study examining Shark ShieldTM‘s effectiveness against white sharks have found that 10 out of 10 times, the shark did not interact with a static bait on its first approach. With subsequent approaches, this rate dropped to 9 times out of 10. Whilst this may suggest habituation to the device, on these occurrences the bait was simply nudged briefly before the shark left the area. The study concluded that the Shark ShieldTM produced an effective deterrent field of 1.3 metres from the device’s electrodes.
To find out more about this promising device, I caught up with one of the lead researchers of the Shark Shield study, Dr. Ryan Kempster, Research Associate at UWA’s School of Animal Biology.
JK: Does the device cause the shark to experience any pain?
RK: The notion of pain in fish is a difficult one to grasp, as we don’t really know how or if fish actually feel pain. Nevertheless, in regards to the electronic deterrent that we tested (The Shark Shield Freedom 7), the sharks definitely feel the stimulus as an uncontrollable spasm of their muscles. It is unlikely that this causes pain, but rather discomfort. It would certainly represent something that is very unnatural to them and so would be something to avoid.
JK: Do the electric signals sent out affect only receptors in the shark? Is there any danger to ourselves or any other forms of marine life?
RK: Previous studies have shown that other marine life are not affected by the device, but it may simply be that they habituate to the stimulus quicker than sharks and so show less response to it. In the case of humans, we can certainly feel the electric field, but it is quite mild and certainly doesn’t cause us any pain.
JK: Why do you think it unlikely to get 100% protection for any shark deterrent, including this newly-patented one?
RK: Shark behaviour is difficult to predict and a stimulation in which a shark may approach someone wearing a deterrent cannot always be controlled. Thus, it would be irresponsible to say that any deterrent could be 100% effective unless you test every possible situation, which is just not practical.
JK: Are you confident enough that if you were to swim with the device, you would feel safe from dangerous interactions with sharks?
RK: Based on the results of our study, I would say yes. Our independent research, published in the journal PLoS One, concluded that upon first encounter with a Shark ShieldTM, all approaching white sharks were effectively deterred by an average of 1.3 metres. After multiple approaches, individual white sharks showed signs of habituation to the Shark ShieldTM, which decreased the effective field of the deterrent by an average of 12 centimetres per approach. However, despite an increase in tolerance, 89% of white sharks continued to be deterred from biting or interacting with the bait when in the presence of an active Shark ShieldTM.
JK: In 2013, WA Premier Colin Barnett introduced ‘baited lines’ and shark kill zones, which were widely condemned by scientists and environmentalists as ineffective, cruel, and damaging to a wider biodiversity. What are your thoughts on how the government handles these attacks on a policy level, and the public fear that ensues?
RK: Lethal shark control programs, like the one in WA, are designed to reduce the incidence of negative human/shark interactions. They do not, however, offer complete protection but instead work on the principle of “fewer sharks, fewer attacks”. In New South Wales, Australia, between 1937 and 2008, 17% of shark bites occurred at beaches with shark nets installed, clearly indicating the ineffectiveness of shark nets to reduce bites to humans. Also, in Hawaii, between 1959 and 1976, a cull of 4,668 sharks including 554 tiger sharks, was carried out to reduce the number of shark bite incidents, yet there was no significant decrease in the rate of shark bites after the cull. Culling sharks does not decrease risk to water users.
JK: Do you want to make any comment on the public perception of sharks as bloodthirsty killers? How do you think this mentality of fear can change?
RK: In a 2012 study of 300 shark-related articles published in 20 major Australian and U.S. newspapers from 2000 to 2010, shark attacks were the emphasis of over half the articles analysed, and shark conservation was the primary topic of just 11% of articles. Despite evidence that many shark species are at risk of extinction, the study found that most media coverage emphasised the risks sharks pose to people. To the extent that media reflects social opinion, these results highlight problems for shark conservation. The authors suggested that conservation professionals should purposefully and frequently engage with the media to highlight the rarity of shark attacks, discuss preventative measures water users can take to reduce their vulnerability to shark encounters, and discuss conservation issues related to local and threatened species of sharks. When integrated with biological and ecological data, social-science data may help generate a more comprehensive perspective and inform conservation practice.
So there you have it: an interesting look into what could be the future of shark deterrent technology. And – perhaps as a result – a new kind of relationship between swimmers and sharks. As any biologist will tell you, sharks are a vital part of our oceanic ecosystems, yet we kill almost 10 million of them every year. When you think about how many sharks are out there, and compare that to the relatively low number of attacks, it becomes clear that shark attacks – though tragic – are an anomaly, rather than a rule. Sure, sharks may be scary. But they are also powerful, beautiful and ancient creatures, and it is their territory we landlubbers intrude. Likely as it is we’ll continue to fear them – they also deserve our respect.
Words by Josip Knezevic