Mega Bite: This Wearable “Force Field” Wards Off Sharks

August 25, 2016Posted by Terry Turner

Thanks to a new invention, the best way to avoid a shark attack is an “electric fence” strapped to your leg.

Shark researchers at the University of Western Australia have been looking for years for the very best way to keep the aquatic apex predators from chowing down on humans.

They’ve recently found a commercially available piece of technology — the “Shark Shield” — an electric forcefield mounted on surfboards or worn on the leg, which is hands-down the best defense swimmers and surfers alike can have against sharks.

The species is one of several marine animals which have an electroreception system, a “sixth sense,” that lets them detect objects and food in the water by sensing electrical waves.

The Shark Shield features a pair of electrodes that dangle like tentacles behind a diver or swimmer, or that can be attached to a surfboard.

Passing an electric current between the electrode creates a three-dimensional, low frequency electric field in the water, which tickles sharks’ electroreceptive system when they get too close, causing them to feel muscle contractions, lose their appetite, and swim away safely for both human and beast.


Photo courtesy: Shark Shield

While shark attacks are rare, they capture media attention and human imagination — sometimes leading to unintended consequences for marine ecology.

The undersea food chain and its environment is heavily dependent on sharks. Culling programs to kill sharks can eliminate a threat to humans, but whole ecosystems can fail if the sharks aren’t there to keep the balance by eating destructive sea creatures.

Finding a way to protect humans without hurting sharks is a key concern in finding a workable, and environmentally friendly shark deterrent.


The Australian researchers last year tested the Shark Shield as well as strobe lights and loud noise makers as potential shark deterrents. The device came out on top in those tests, and the scientists set up a second round of experiments this year focused solely on the Shark Shield’s overall effectiveness.

They attached the device to bait and gauged how it performed in 322 encounters with 41 different white sharks ranging in fear-inducing length from six to 12 feet. The Shark Shield was 100% effective in warding off sharks on their first approach, never letting them get within four feet of the bait.

Lead researcher Dr. Ryan Kempster said only one white shark in the tests ever interacted with the bait, and that was only after multiple passes at it.

Shark Shield Leg

Diver wearing Shark Shield on lower right leg. Courtesy: Shark Shield

“Although the effectiveness of the Shark Shield likely varies between species, the fact that white sharks are implicated in the majority of fatal incidents globally suggests that a deterrent that effectively deters this species should be an important safety consideration for ocean users,” Dr. Kempster said.

The team published their findings in the journal PLOS ONE.

They point out that while it’s the most effective deterrent they’ve found after decades of testing, it still can’t guarantee you’d be 100% safe from a shark bite. But it can buy you time to get to safety.

…and after realizing you’ve had a close encounter with a shark and survived — you might realize you can swim to shore faster than you ever expected.

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