Nevertheless, with increased media attention surrounding the few incidents that occur each year, there are repeated calls for action to be taken to reduce what is already a very low risk.  Unfortunately, these situations can quickly get out of hand, which is what we saw in Western Australia (WA) in 2014 when the Government  began culling sharks in a misguided attempt to reduce the risk to swimmers.  A total of 172 sharks were caught (almost all tiger sharks), and eight other animals including stingrays, however not a single great white was caught, despite this species being identified as the one involved in the fatal incidents that sparked the cull in the first place.

Given the vital role that sharks play in the health of marine ecosystems, it is essential that we avoid destructive control measures, such as those undertaken in Western Australia.  Instead, we must develop non-lethal methods to allow humans and sharks to coexist safely.  As a result, our research scientists at SOS, in collaboration with partners at the University of Western Australia, have embarked on a mission to test and develop non-lethal shark deterrents to provide ocean users with an extra level of protection against negative interactions with sharks.

Previously, we reported the success we observed with an electric deterrent, the Shark Shield, which was able to effectively deter great white sharks from interacting with a baited canister.  In our latest research, we focused our attention on the potential effect of auditory and visual signals on shark behavior.  We were interested to see if by simply playing a sound or flashing a light, could we manipulate the behavior of an approaching shark? 

The artificial sound that we created for this study was based on the work of Myrberg et al. (1978), which showed that a sound with a rapidly changing amplitude and frequency elicited a deterrent behavior in free-swimming sharks.  In an attempt to increase the potential deterrent effect of the audio signal, we only activated the sound as white sharks approached within approximately 2m of the audio source.  This was to reduce the chances of the sharks habituating to the sound as they approached from a distance.  Nevertheless, we did not observe a significant deterrent response to the artificial sounds presented.  Neither did we observe any significant deterrent response when the sharks were presented with a flashing strobe light.  However, when the auditory and visual stimuli were presented in combination, white sharks spent significantly less time in close proximity to the bait.  Furthermore, this effect was even more pronounced in smaller benthic shark species that we tested.

As the presentation of lights or sound alone did not show a significant deterrent effect on white sharks in this study, we do not advise their use as a strategy for mitigating shark–human interactions.  However, due to their potential combined effectiveness, particularly with other species of sharks, there may be applications for this approach in deterring specific species from fishing hooks or nets to reduce fisheries bycatch. 

We still have much to learn about how sharks utilize their senses to perceive and interact with their environment, but our hope is that our efforts will one day bring about practical solutions to help humans and sharks coexist peacefully.