Shark Shocker Tested

Let's face, some divers -- and certainly some surfers and swimmers -- are paranoid about shark attacks, and there will always be someone ready to sell them a magic device to avoid that happening. Of course, the problem is that you don't know if it works. You only find out if it doesn't work, and by then it's usually too late.

There have been some pretty revolutionary ideas out there, including magnetic wristbands, wetsuits that are meant to taste bad to sharks (by the time the shark has spat you out, it's probably a little late) and even drones to keep watch from above. Now a new study has found some value to an older idea using electrical impulses to scare off would-be predators.

University of Western Australia researchers have produced the most robust analysis of any such electrical device so far. The study used stereo camera technology to accurately determine the exact proximity that a white shark approached an active Shark Shield device. Lead researcher Ryan Kempster and his team fixed the Shark Shield to a rig in the waters off South Africa and attracted sharks with a bait-loaded canister. The team recorded 322 encounters with 41 individual sharks ranging from 6 to 13 feet in length.

The setup created a deterrent field with a radius of about 4 feet and stopped the sharks from taking the bait 100 percent of the time on their first approach. However, the animals did become accustomed to the electrical impulses, and this success rate dropped to 90 percent and the field reduced by an average of 5 inches each time the same shark approached. Eventually, one can assume, the shark would finally reach the bait, but if the bait were a human, he might have enough time to get out of the water.

In 2008, a surfer was killed by a great white shark while using this or a similar device, and Kempster was quick to add that although they now know the exact electric field characteristics that will deter a shark, it does not imply that other devices will be as effective. The research is funded by the Western Australian state government.

(Source: University of Western Australia)