Shark Shield – Electronic Shark Deterrent Technology
Myth or Legend?
Shark deterrent technology: Hear the facts. You decide.
Amanda Wilson, Managing Director Shark Shield Pty Ltd
With such heated debate about the conservation of sharks, and the natural desire for safety in our waters, the use of electronic shark deterrent devices has become a necessary conversation that we simply must have. There is much speculation about the offered products, and for those that have that amphibious streak, there are a few pressing questions that are being asked: Does shark deterrent technology actually work? How does it work? And does it attract sharks and then deter them? Could an electronic deterrent device, such as Shark Shield FREEDOM7, be the newfound legend in our waters?
Firstly, a shark deterrent has to be one that has the capability of producing a low frequency that disturbs the electro reception in a shark. Here is where the scientific hat must be worn, because to understand how the deterrent technology works, there has to be some understanding of what we are trying to deter, and for that matter, protect.
All Chondrichthyans: sharks, rays, skates and chimeras, have Ampullary receptors in their heads, these are broadly tuned to low-frequency fields of <0.1–25 Hz, and believe it or not, these are the same electroreceptors that Australia’s beloved Platypus and Echidnas have. They all use them for the same thing, to find prey hidden under wet sand, to communicate to each other, to find a mate when the mood beckons, and to detect potential predators. This sensitivity is only operational when in close proximity, it is the final stages of detection for them all, including our sharks.
This is where it gets very interesting, Shaun Collins, a world expert on, ‘Electroreception in Vertebrates and Invertebrates’ (Collins et al) reports that all of the research on the many animals that have ampullary or tuberous organs, keeping in mind that this enables them to detect weak electrical fields, be it low or high frequency, only use it after they have used chemoreceptive, mechanoreceptive and their vision to localize their prey. In laymen’s terms, they detect particles in the water, vibration in the water, what is seen and then, the ampullae/mucus gland kicks in at a close proximity, and this is when an electromagnetic field is detected. As the waves emitted from an electromagnetic field do not travel great distances under water, and the sharks Ampullary receptors only fire up when it is close to its prey, it is an impossibility that this shark deterrent technology attracts sharks. This is because by the time the shark senses the electrical wave, he has a pain that travels like lightening through the gel in the receptors in his head giving him a headache of whale proportions which has him fleeing for calmer waters.
Shark deterrent devices are basically two electrodes that emit an electromagnetic field in a low frequency that interferes and greatly disturbs the shark’s electroreceptor. The extensive research, in fact over 20 years of it by the Zwazulu Natal Shark Board in South Africa, patented a successful model, which subsequently was thoroughly tested. The result, the sharks did not like it, and since then many organisations and private users have attested to its obvious deterrent capability. The reason the deterrent works is that it creates a low frequency that specifically targets sharks, but note that for full protection the electrodes need to be far enough apart to create an electrical field that surrounds the user. Electrical waves do not travel far under water so it is also crucial that the device is powered sufficiently to create an electrical field at least four or five meters in diameter.
The scientific jargon can sound very bewildering, yet a desire to gain trust and some hope in something tried and true, for the safety of all seems very necessary. So with this, steps toward assurance continue in the water itself. The original technology was released onto the market in 1995 by POD Holdings Ltd, a joint venture company partly owned by the Zwazulu Natal Shark Board and the South African Government. In addition to being tested by National Military and other authorities, the Shark Shield SCUB7 and FREEDOM7 have been extensively tested to the highest standards by scientists and marine biologists over many years.
The accumulative years of research by scientists and world-recognised organisations cannot be wrong, nor can the fact that the Shark Shield product has been used well over a decade by professional divers, the U.S Coastguard, the American and Australian Navy. This product must be seriously considered as a safety device in the water against a shark attack, just as wearing a seatbelt in a car is a safety choice. If it has kept this many citizens safe, and our Navy will not dive without one, then the message seems loud and clear. If the product conforms to what science knows works, and be aware that not all of the electric shark deterrents do, so do your research, then this seems the way to real conservation. True, conscious conservation of the ones we love and of sharks. The immediate and accessible solution, and the answer to the question must be that this product is the new legend in the water.