High Tech Shield to Prevent Shark Attacks

31 July 2012

18 October 2012


Five people have been killed by sharks off Western Australia's southwest coast in less than a year. 

Sharks have a sixth sense, allowing them to detect electro-magnetic fields caused by the movement of fish and other potential prey.

Ocean-lovers in Cape Town are using a device that repels sharks by emitting an electrical wave form.

The Shark Shield was invented in South Africa in the 1990s, and is now made in Australia.

Divers of University of Cape Town Zoology Department are among users of the Shark Shield.

Andrea Plos, head diving supervisor, explains where the elliptical field that surrounds the user emanates from.

"It's the whip part of your shark shield, and it dangles behind you, and what you must try to make sure is that no one bumps into it or touches it. It will tend to give you a bit of a shock."

For Plos and these University student divers, having the shark shield gives peace of mind.

"As scientific divers we spend a considerable amount of time in the water, often in high risk areas, and with zero visibility, and it just adds a level of safety and reduces the risk while in the water."

Thus far the shark shield has proven its worth.

"We've never had any incidents while wearing the shark shield, and we have dived in very risky areas with lots of Great Whites," says Plos.

What the shark shield deterrent does is to overwhelm the sixth electric sense that shark's possess. 

As the shark comes closer to the device, increasingly uncomfortable spasms occur in the snout area, which should then result in the shark veering away.

Other shark shield users include surfers, such as Neil Uys.

He feels safer with the device attached to his surf board, even though he is concerned about sharks that may be in attack or predatory mode.

"If you drive carefully you can kind of avoid accidents. When a Great White shark has got you in its sights, then there's very little you can do, and you kind of maybe get a bit of comfort out of this device."

A recent Australian study on the effects of the shark shield on the behaviour of Great White Sharks is now complete.

Alison Kock was one of the scientists involved in this study that tested the device under baited conditions when the sharks were calm, and using a seal decoy when the sharks were in predatory mode.

"What we found was that the shark shield had an impact on White Shark behaviour when we used the seal decoy, and we had significantly fewer predatory interactions with the seal decoy when it was switched on. And under the baited conditions we found that it impacted their behaviour by them being more cautious around it when it was switched on".

The last shark attack at Fish Hoek beach was in 2011. 

At the lifesaving club here, the Water Safety Manager has developed a novel application of the shark shield.

"What we've done here is that we've got the shark shield, the freedom seven mdel shark shield which we've adapted to suit our needs which is to attach them to a buoy which we put into the sea, and we put the buoys ten metres apart."

With the effective electronic radius approximately five metres, Mike Schilperoort dangles the shark shields from 25 buoys placed at ten metre intervals.    

The theory is that this creates a 250 metre shark shield.

This is used for lifesavers training at the club.

One of the lifesavers is Samantha Alford.

Alford feels confident swimming in these waters because of the shark shield and the shark spotters who warn swimmers of sharks.

"A lot of people think that the sea is a dangerous place, but for me it's my home, it's where I've been brought up, I love it. I feel very safe with the lifeguards and the shark men and the shark shield."

Mike Schilperoort has a big responsibility for the safety of the lifesavers at Fish Hoek beach, which has had its fair share of Great White Shark sightings, and four attacks over the last six years. 

The shark shield offers some peace of mind from Great White and other predatory sharks. 

"We feel it's designed to be a distraction. In other words, if it comes into the area it would rather move away from the electronic fields that these things produce, than move into the zone where we've got swimmers."

For the sake of sharks and people entering the ocean, all shark-human conflict mitigation methods need to be researched, and utilised, even if only partially effective.