Do shark repellants work?

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Do shark repellants work?

June 18, 2018 - 19:01
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Australian researchers have put five of the most popular shark deterring products to the test. Only one seemed to work.

Which shark repellants actually work and which are just hype? (unrelated file photo)

Prevention and responses to shark bites have varied temporally and regionally, and have included shark hunts, organised shark culling, beach meshing and drumlines, beach closures, shark fences, land and aerial based shark spotting, and acoustic telemetry. While these measures aim to reduce the probability of sharks and humans encountering each other, other measures aim to repel sharks directly from approaching people in the water.

These deterrents have been developed to elicit a response by impacting one or more of the shark senses, including vision, smell, and electro-reception.

Do they work?

Charlie Huveneers at Flinders University in Australia and his colleagues decided to put five of the most popular shark deterring products to the test. These included two devices that create electric fields, two that create magnetic fields, and a smelly surfboard wax: Shark Shield Pty Ltd [Ocean Guardian] Freedom+ Surf, Rpela, SharkBanz bracelet, SharkBanz surf leash [Modom], and Chillax Wax.

Trials were conducted at the Neptune Islands Group Marine Park off the coast of South Australia. Each deterrent was attached to a surfboard and a piece of tuna bait was dangled below the board to mimic a surfer’s foot, and an underwater camera recorded any shark interactions. A total of 50 trials were conducted per product.

The researchers compared the percentage of baits taken, time to take the bait, number of passes, distance to the bait, and whether a shark reaction could be observed. A total of 297 successful trials were done at the Neptune Islands Group Marine Park. During these trials, 44 different white sharks (Carcharodon carcharias) interacted with the bait, making a total of 1413 passes.

Only one device worked

Of the five products only the electric device made by Australian company Ocean Guardian had any significant effect. It halved the number of shark attacks on the bait. The device attaches to the tail of the board and is designed to create a strong electric field. The aim is to overwhelm the sensory receptors that sharks use to detect weak electric signals of their prey, says Huveneers.

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