After a fatal shark attack in KuGompo, do shark-repellent bracelets actually work?

Janine Lochrenberg was wearing a shark-repellent device when she was killed in a shark attack in KuGompo.

The 65-year-old was a passionate open-water swimmer.

She and her fellow swimmers wore magnetic shark repellents on their feet.

But it wasn’t enough to save her, and scientists say the research raises serious questions about these devices.

On Tuesday, 20 October, Lochrenberg was killed by a shark while swimming with a group at Orient Beach in KuGompo City, formerly East London.

WHAT HAPPENED AT ORIENT BEACH

Lochrenberg, a retired nuclear radiographer and musician, was swimming with a group shortly after 08:00 when she signalled that she was in trouble.

Fellow swimmer Mike Loewe was in the water with Lochrenberg when the attack happened.

“We were all in the water, swimming. We were wearing [magnetic shark repellents] on our feet. She had one on,” Loewe told SABC News.

A witness told SABC that she had suffered two severe bites, one on her thigh and one on her upper arm.

She was declared dead at the scene. Police have opened an inquest, and the species of shark involved isn’t yet known.

The Buffalo City Metropolitan Municipality has closed Orient Beach and nearby Eastern Beach until further notice.

According to municipal records cited by the Associated Press, it’s the city’s first fatal shark attack since 1997.

DO SHARK-REPELLENT BRACELETS WORK?

According to the research, probably not.

In 2018, scientists at Flinders University in Australia tested five popular personal shark deterrents in waters with one of Australia’s largest groups of great white sharks.

They tested two magnetic devices, including a bracelet, two electric devices, and a surfboard wax designed to repel sharks by smell.

Each device was attached to a surfboard, with bait dangled below to mimic a surfer’s foot.

The team carried out 50 trials for each product.

The study found that only one electric device had a significant effect.

The magnetic bracelet didn’t.

WHAT ABOUT ELECTRIC DETERRENTS?

The electric device that worked creates a strong electrical field, designed to overwhelm the sensors sharks use to detect the weak electrical signals given off by their prey.

“We found that this electric deterrent reduced the risk of a shark bite by around 60%,” shark ecologist Charlie Huveneers, of Flinders University, told Cosmos magazine.

A later study found that personal electric deterrents reduced bites from great white, tiger and bull sharks, the three species responsible for most severe shark bites around the world. But neither product it tested eliminated the risk entirely.

Not all electric devices work equally well, either.

Researchers at the University of Western Australia found that electric deterrents compacted into an anklet were ineffective.

A FALSE SENSE OF SECURITY

Scientists warn that ineffective deterrents could put people at greater risk.

Huveneers has said some people wearing ineffective deterrents visit high-risk surf spots they would normally avoid, such as breaks near seal colonies, and even return to the water after a shark has been spotted.

“There is currently no silver bullet that will completely stop the risk of shark bites,” he said.

HOW COMMON ARE SHARK ATTACKS IN SOUTH AFRICA?

Shark attacks are rare.

The Florida Museum of Natural History’s International Shark Attack File recorded 29 unprovoked shark bites in South Africa between 2012 and 2021, an average of about three a year. 

Six were fatal.

HOW TO STAY SAFER IN THE WATER

No device can guarantee your safety, but shark safety organisations recommend:

• Swimming at beaches with lifeguards, and staying within the safe swimming areas.
• Obeying beach closures and shark warnings.
• Avoiding the water at dawn and dusk, in murky water, and near river mouths.
• Not swimming alone.
• Staying away from areas where people are fishing, or where there’s bait in the water.