Electrical Shark Repellent
For over a decade the KZN Sharks Board experimented with the use of electrical fields to repel sharks. In 1996 this culminated in the development and sale of a successful electrical shark repellent, the SharkPOD (Protective Oceanic Device).
The SharkPOD Diver Unit was specifically designed for use by SCUBA divers. Most of the sales were to commercial divers, as recreational divers want to see sharks rather than repel them. The concept was later modified for use by commercial, surface-supply divers, who obtain their air from the surface via an airline.
The SharkPOD Diver Unit consisted of three components linked by cables. The main body of the Diver Unit, housing a small rechargeable 12 V battery pack and one stainless steel electrode, was strapped to the dive cylinder. The foot electrode was attached to one of the diver's fins.
The activating switch, which also housed the low battery warning light, was brought over the shoulder to make it easily accessible. Separated by at least 1.5m, the two electrodes created an electrical field around the diver, which was designed to repel sharks approaching from any direction. This field appeared to affect the shark’s sensory and neuromuscular systems and discouraged the shark from remaining in the immediate vicinity.
The SharkPOD proved effective in scientifically controlled field tests, repelling sharks that came "too close for comfort" (i.e. 1m from the SharkPOD). Most of these tests were conducted on white sharks Carcharodon carcharias on South Africa’s southwest coastline, which is internationally renowned as the best region in which to encounter this species. Tests against the other two species of dangerous sharks which divers are likely to encounter in nearshore waters, namely the tiger Galeocerdo cuvier and the bull (Zambezi) shark Carcharhinus leucas, were limited but with good results. The effectiveness of the device varied according to species, and some harmless sharks, such as the nurse shark Ginglymostoma cirratum, showed little reaction to the electrical field.
The SharkPOD Diver Unit was designed to be activated immediately on entering the water and switched off again only when leaving the water. The device was not intended to be switched on and off during a dive as a startle device - it functioned by keeping sharks at bay. When used correctly, the electrical field was not strong enough to cause undue discomfort to humans.
Distribution of the SharkPOD ended in 2001, but the rights to use the waveform patented by the KZNSB were granted to an Australian company, SeaChange (now called Shark Shield), which now produces repellent devices for use by individuals. Please contact the KZNSB for information regarding suppliers in South Africa.
Shark Repellent Cable
The KZNSB is investigating the possibility of using its patented waveform in a shark repellent cable (SRC) that potentially would surround an entire bathing area with an electrical field. In 2010 the organisation contracted the services of physicists and electrical engineers to assist with this line of research. The project is ongoing.