Shark-repelling device rather dramatically fails real-world test (Update)

See update below for response from the Sharkbanz company.

A product called “Sharkbanz” is getting some terrible publicity today as a Florida teenager wearing the magnet bracelet was bitten by a shark prompting questions about how useful this product actually is.

Wearing shark repelling band, Teen gets attacked by shark

Zack Davis was a lifelong surfer and fished for shark regularly. This was the first time he’s had a close encounter with a shark. Ironically, he thought he was better protected this time.

Zack was wearing a new band with magnetic technology that advertises it repels sharks away from swimmers.

“I got this for Christmas,” Zack said, showing us the green plastic band that looks like a watch with no face, “It is a shark band and it was supposed to keep sharks away and the first time I wore it, and I go surfing a lot, but the first time I wore it- I get bit.”

Zack is recovering fine with 44 stitches from a bite from what is suspected to be a black tip shark.

sharkbanzThe idea behind the Sharkbanz device is questionable and smacks of Power Balance bands,  magnetic healing bracelets, and other hyped pseudoscientific “technology” that sounds plausible but is more like a gimmick. The Sharkbanz appear to be just strong magnets within a strap. There are no batteries.

There are several types of shark repellent advertised including electropositive, electrical, and chemical repellents. Sharks have highly sensitive electrical receptors in their snouts that the makers of such electric and magnetic devices say are affected by their devices. The research results are mixed because not all types of sharks respond the same and some use other senses to trigger and focus an attack. But, the SharkBanz idea seems highly implausible anyway. A small magnet is not going to do much of anything against a shark in a chaotic environment. In this case, it could be argued that it may have attracted the shark. The device has been out for over a year. An Australian outlet asked the question if it worked. Instead, the article served as an advertisement for the product in a completely uncritical review that just repackaged the company’s claims. Here are some of those claims from their website:

Sharkbanz are an easy way to add peace of mind to the everyday ocean swim, surf, or snorkel, but make no mistake: the science is real. We enlisted the services of the renowned shark experts at SharkDefense Technologies. This group of scientists founded the organization 15 years ago, and created breakthroughs in a variety of shark deterrent technologies through their research and development.

The company provides 13 pages of explanation of the technology and links to the research papers. Some of the research is based on tests in controlled environments with magnets, not with magnets on people. Such results may not be translatable or repeatable.

Sharkbanz use special patented magnetic technology to deter sharks from attacking people. Most shark attacks occur in murky, shallow waters off the coast where there are a high number of swimmers and sharks sharing the same space. In this environment, sharks rely heavily on their electro-receptors instead of their eyes to “see” what’s around them. They possess the most sensitive electro-magnetic sense of all known animals, and use it to judge distance, shape, and even the heart rate of other animals near them. Most of the time, sharks get it right and leave people alone. Occasionally, they don’t. Sometimes when relying on their electro-receptors, a curious shark may bite a person in order to figure out what he or she is. These unprovoked “hit and run” attacks are the most common type, and Sharkbanz are an excellent defense against them. As the shark approaches a person wearing Sharkbanz, magnetic waves coming from the band disrupt its electro-receptors and it quickly turns away.

Well, that didn’t work out! The scenario given for the Sharkbanz protection was exactly the situation in which Zack was attacked. Those who wear such devices can get a false sense of security and may be less aware or careful.

Shark researcher David Shiffman doubts the claims of repellents. He tweets:


SharkBanz does not guarantee their product 100% because animals are unpredictable. An argument arises, though, if it’s reasonable to even suggest to consumers that the product provides any measure of safety at all.

At least Zack is going to be OK. His mom wants her money back. She should certainly get back double.

Thanks, David Bloomberg, for this story.

31-Dec 2016 Update

The company has sent their official statement on this incident to DN. They contacted Zack immediately and report that HE believes “the encounter and bite were a case of rare bad luck” and that he “accidentally provoked” the shark who reacted in a defensive manner.  It contains some questionable special pleading:

Our scientific partners and shark researchers at SharkDefense Technologies have concurred with this self- defense assessment of the shark’s behavior. Managing Partner and Sr. Chemist of SharkDefense Technologies, Dr. Eric Stroud, a leading expert on magnetic shark deterrent technologies, noted, “If the surfer did land on top of the shark or very close to it, the shark would have likely acted defensively to this. While accidental and certainly unlucky, this is essentially a provoked attack from the shark’s perspective. If the animal was cornered relative to the shore, the surfer’s body, and physical contact occurred near the shark’s head, the shark acted as expected. In a provoked attack situation, shark repellents are no longer effective.”

Additionally, Dr. Stroud believes that the Sharkbanz being worn on the opposite wrist could have been the very reason the shark let go of Zack’s affected arm so quickly and fled the scene. “Such types of encounters are very rare; this attack was certainly a very unique chain of events. Sharkbanz were designed to reduce unprovoked investigatory bites of the ankles, calves, and feet, which is the most common bite site for the United States. I believe that permanent magnet technologies and Sharkbanz remain effective for these situations.”

screen-shot-2016-12-31-at-12-20-43-pmFor the news media, this response would be fine. But I’m not the news media and I see some serious problems with this statement. According to Zack, he landed on the sand, not the shark. Now, he provoked it? Also, what is the support to describe this event as rare? I don’t see such encounters between sharks and people as rare at all, but most times the sharks in shallow water, late in the day, will not attack people but will instinctively retreat. The odds that you will be attacked as prey (unprovoked) by a shark are not high. Most sharks are intent on finding their usual prey items, not people. The company uses the term “unprovoked investigatory bites” to describe the protection scenario and seem to suggest you need to buy four bands, one for each limb, to be thoroughly covered. And not accidentally land too close to a shark. So, yeah, they do sound like they are blaming the victim. Not cool.

What should they have done and said? They should have stated they gathered important information about this incident and took it back for further investigation into the efficacy of the product. They didn’t say they were going to do that. Instead, they doubled down and said it wasn’t their fault admitting they remain convinced by their research. That is unscientific. Go back and retest your device. Funny, I don’t find many other shark researchers other than their own people endorsing this product. If there are some, I’d feel more positive about it.

Essentially, the conclusion from this event is that you can NEVER be fully protected from sharks if you are in their element. I’d suggest you deal with the odds, take reasonable precautions, and not waste money on devices that sound sciencey but have not been adequately tested in real world scenarios (and that you really don’t need). Obviously, this device did Zack no good. To suggest the shark that bit him retreated because the band was on the other hand is a fanciful, subjective claim.

Sharkbanz also concluded the statement by saying they are continuing to seek out negative-sounding pieces about this event in order to spin it so they don’t look bad. Well, they didn’t say it that way, they said they are working to  “properly relay the facts and science behind our product’s technology.”

Be skeptical.

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