Repellents toothless

SOME costly shark repellents do not stop the marine predators approaching swimmers or even protect their whole bodies, research has revealed, and experts warn they could prove more dangerous than using no technology at all.

New tests, conducted by researchers from three Australian universities, labelled Electronic Shark Defense System devices “unreliable” and ineffective against sharks despite commanding more than $700, and found they left large parts of swimmers’ bodies completely exposed to attacks.

The news comes after a prolific run of shark attacks in Australia, with more than 27 incidents in 2018 and another five attacks so far this year.

Shark experts said Australia needed to invest more in sharkrepelling technology, but warned there was “no silver bullet” that would make it entirely safe to swim in open water.

The latest research put the Electronic Shark Defense System (ESDS) device to the test in South African waters.

The device, available at dive shops in Australia, is a small, battery-powered anklet that retails for $750 and is designed to emit electrical pulses that are picked up by sensitive receptors in sharks’ snouts.

But the study found white sharks “routinely” swum within 20cm of the “deterrent,” and it was no more capable when turned on than when off.