Shark repellents have been of interest to human beings for many years. Principally, they have been used to protect ocean users from potential 'attack', but also serve multiple other functions. For example, fish caught in a net or on a line may be a very attractive prospect to a passing shark and so a repellent may serve to protect a fisherman's catch. In addition, sharks themselves are sometimes caught inadvertently by fishermen and so repellents may prevent unnecessary deaths. Therefore, shark repellents may also be used to protect sharks by driving them away from areas where they are likely to be killed by human beings; in this case, shark repellents may be considered a useful tool in the conservation of sharks.
"Shark repellents may also be used to protect sharks by driving them away from areas where they are likely to be killed by human beings."
Some of the earliest serious research on shark repellents took place during the Second World War when military services sought to minimize the risk, both real and imagined, to stranded pilots and sailors in the water. Studies at the time, combined with historical research, revealed that the only thing that will drive sharks away is the odor of another dead shark. Therefore, efforts were made to isolate the active properties of dead shark tissue. Eventually, it was determined that certain copper compounds, such as copper sulfate and copper acetate, in combination with other ingredients, could mimic a dead shark and drive live sharks away from human beings in the water. For years, a combination of copper acetate and dye was supplied to sailors as a shark repellent.
The search for an effective shark repellent
Today, the search for a truly effective shark repellent is still ongoing but there are a number of options that may provide a solution in the future. Below are some potential repellents that are currently being investigated.
Electrical devices that disturb a shark's delicate ampullae of Lorenzini seem to be at least partially effective but more research is needed to assess the repellent variation between species.
Some research, based on chemical repellents, looks promising. Research indicates that sharks will avoid an area once they smell chemicals released by dead and dying sharks.
Sharks have been shown to be attracted to music when played at specific frequencies, more specifically ACDC is apparently a favourite of the white shark. By studying the ears of sharks we can start to understand the thresholds of there ability to detect sound and therefore determine the specific frequency ranges that attract and repel sharks.
See Shark Stopper
Sharks are effectively colour blind, and so only see in black and white, therefore contrast is very important. As a result, it has been suggested that high contrast wetsuits (such as a typical black suit) may actually make you more visible to a shark and therefore more likely to be investigated by a shark. Wetsuits that camouflage you in the water may actually help to hide you from sharks allowing you to go unnoticed. The same principle may also be applied to surf boards.
repellent research by SOS
SOS is actively working towards producing effective shark repellents by studying the sensory systems of a range of sharks. From our wealth of knowledge in this area, we know that of particular importance is to ensure that a shark doesn't become conditioned to a repellent. For example, if a shark gets used to a stimulus, even an unpleasant one, the stimulus will eventually become ineffective at repelling the shark. We aim to develop repellents that will always be effective irrelevant of how long a shark has been in its presence. For more information on our research check out the documentaries below.
ABC Catalyst: Shark Repellents (aired 03-05-2012)
In this documentary, Dr. Graham Phillips discovers how understanding a sharks' sensory system may help people swim safely amongst these carnivorous fish. ABC followed us during the early stages of our research into potential shark repellent solutions, using visual, acoustic and electrical stimulants.
ABC Catalyst: Sell your science - Survival of the
stillest (aired 13-02-2012)
ABC Catalyst: Sell your science - Survival of the stillest (aired 13-02-2012)
Shark Biologist and founder of Support Our Sharks, Ryan Kempster, shares with you the amazing senses of embryonic bamboo sharks. The film documents the avoidance response of embryonic bamboo sharks when presented with predator mimicking electric fields.
This film was also chosen to be screened at the 2012 Beneath the Waves Film Festival.