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A Shark Shield is an electronic device which is meant to deter sharks from surfers, divers, boaters, and swimmers. The device is manufactured for consumers by SeaChange, an Australian company, and sold through a variety of distributors around the world. The Shark Shield carries a hefty price tag, so it is not for everyone, but some people feel that the safety advantages of the device justify the cost. Dive and surf supply shops may carry the device or be able to order it, and it can also be purchased through online retailers.
Early versions of the Shark Shield were developed in South Africa, a region of the world with notoriously shark-infested waters. Researchers there took advantage of the electrical sensitivity of sharks, creating a device which generates an electrical field that makes sharks feel uncomfortable, causing them to swim away. When sharks enter the field created by a Shark Shield, they experience involuntary muscle spasms which are supposed to encourage the shark to find a snack elsewhere.
To use a Shark Shield, someone can either wear the device or attach it to a surfboard, boat, or set of diving gear. The Shark Shield is turned on when entering the water and left on throughout the session in the water, and turned off upon exiting. According to SeaChange, users should not notice the electrical field unless they come into direct contact with the electrodes, and the device comes with a user's guide which needs to be followed carefully for best results.
Sharks are naturally curious animals, and in field testing, researchers have observed that when sharks sense the electrical field created by the Shark Shield, they often swim closer to investigate. This can lead to the idea that the Shark Shield actually attracts sharks; however, when the sharks cross the barrier of the field, their curiosity is typically satisfied, and they leave the area.
Like any product which is designed to repel sharks, the Shark Shield does not come with a guarantee. It has certainly been shown to be effective in many tests, and users often report satisfaction with it, but malfunctions do arise with electronic items, and sharks are not always predictable, so a particularly determined or stubborn shark could still attack someone wearing the device. It is also important to remember that the Shark Shield does not protect people from other dangers, like storm surge and other curious sea creatures.
@KoiwiGal - I think a lot of the time when they use shark cages it's because they've used some kind of bait in order to get a bunch of sharks into the area.
In that case you really wouldn't want to rely on a device like this. I don't know how much it affects sharks but when they go into a frenzy I imagine all bets are off and they might just ignore the annoying sensation that's gently urging them to leave.
Even the cage would make me nervous to be honest. A full grown great white in a frenzy must be incredibly strong. You'd have to really trust the maker of that cage.
@croydon - Well, the shark shield is electrical, not physical really. But I'm not sure how much they knew about sharks back then.
Now we know that they sense things through sensing electrical fields in the water. It makes sense that they wouldn't like a strong electrical current, just the same as we wouldn't like a very loud noise.
And I think this is a better method of repelling sharks than using chemicals, as there is no way that the field will harm the shark, the swimmer or other fish.
I can understand why people would want to have one of these when just reef diving as the idea of a shark attack is pretty scary.
If I was going to swim with sharks deliberately though, I think I would prefer to stick to a shark cage, rather than rely on a this kind of device.
Something I always found truly strange and wonderful is the fact that the famous chef Julia Child worked on developing a shark repellent during World War Two.
She was working as a secretary for the war effort when they realized that she was quite well educated and eventually she ended up helping with this project. They needed to know how to repel sharks in order to keep them from exploding the underwater bombs they were hoping to send against the Germans.
It was before she was a chef but it just seems like such an amazing thing for someone to do in their past life. The kind of job that every writer wants to be able to put on their "about the author".
Of course, they couldn't use a physical shark shield to protect the bombs as that would be impractical. It was easier to come up with some kind of chemical to put in the water and stop them from coming near at all.
I don't know how successful they were though.