That California Swimmer Killed by a Shark

After a shark attack injured one of their own nearly three years ago, members of the Kelp Krawlers -- who swim weekly around Lover's Point in Monterey -- began wearing shark deterrents, including SharkBanz, magnetic ankle bands designed to overwhelm a shark's electroreceptors -- the sensitive "sixth sense" pores they use to detect the faint electrical heartbeats of nearby prey.

On December 21, Erica Fox, a seasoned triathlete and Kelp Krawlers member, was leading a group of swimmers off Lover's Point when she was attacked by a shark while wearing a SharkBanz. Three Witnesses reported seeing a shark breach just offshore at Lover's Point that morning. Her body was recovered 25 miles from where she was last seen. Her husband said she was still wearing her wetsuit, a Garmin fitness tracking watch, and the SharkBanz around her ankle.

Her death sparked scrutiny among swim club members about whether the devices meaningfully reduce risk. Many of them had purchased SharkBanz, because great white sharks are common along California's coast. SharkBanz says its bands can deter great white sharks that are merely "investigating" prey, because they rely on electroreception while swimming in open water. The company also acknowledges on its website that the product does little to deter ambush attacks when great whites strike at high speeds from below.

"SharkBanz does not claim to eliminate shark bite risk or provide a specific percentage reduction," the company told the Bay Area News Group. "Shark encounters are rare, unpredictable events influenced by many environmental and biological factors, making precise risk-reduction figures scientifically unrealistic for any personal deterrent."

Despite its limitations, SharkBanz markets its product as "proven, effective, and safe," and says it "reduces the risk" of shark encounters by emitting electromagnetic fields.

Another product, Australian-made RPELA, which attaches to surfboards, says its product "makes it extremely unpleasant to be around," adding that "extensive testing has been carried out with predatory sharks with outstanding results." SharkOff uses a low-voltage field intended to make sharks "jerk away" from the device, while Ocean Guardian claims its product causes "harmless but unbearable spasms" that prompt sharks to swim away.

Independent research has cast doubt on many of those claims.

A 2018 Flinders University study in Australia tested five personal shark-bite deterrents -- Freedom+Surf by Ocean Guardian, RPELA, SharkBanz bracelet and leash, and Chillax Wax -- during nearly 300 open-ocean trials. Only one electrical device, Freedom+ Surf, reduced shark interactions by more than half. The other products showed little or no measurable effect.

SharkBanz disputed the study, saying the testing conditions were not designed to evaluate wearable magnetic devices as they are intended to be used. "The use of a large, highly attractive tuna bait suspended well beyond the effective range of permanent magnets represents an extreme, worst-case scenario," the company said.

RPELA also disputed the findings, citing an independent 2021 study published in the Journal of Marine Science and Technology-Taiwan that found its redesigned "v2" model reduced the likelihood of great white shark bites by 66 percent and overall interactions by 38 percent.

Carl Meyer, a research professor at the Hawai?i Institute of Marine Biology, has been studying multiple wearable shark deterrents, including SharkBanz. One key limitation, Meyer said, is the extremely small range of the electromagnetic field the devices emit -- a range sharks are unlikely to detect until they are already very close.

"A shark has to be within about 3 feet to even detect the field from a SharkBanz bracelet," Meyer said. "At that distance, the field strength is well within the range of natural electromagnetic signals sharks routinely encounter. There's nothing inherently alarming about it."

Meyer also criticized how such products are marketed, particularly the repeated use of phrases like "reduce the risk . . . Mainstream safety products typically provide clear, quantitative risk-reduction numbers, which I have not seen for this device," he said.

SharkBanz said that while magnetic deterrents have limits, independent, peer-reviewed studies have shown they can alter shark behavior at close range, including "avoidance and reduced engagement with targets."

Many of Fox's fellow swim club members said they were aware of the research -- and its limitations. "All of us will openly admit that we hold on to certain things, knowing that it gives us a false sense of security," said Lisa Jensen, who swam regularly with the Jensen SharkBanz. "offered all of our members a discount code," Carey said. "And so, of course, we all got them."

SharkBanz said it was saddened by Fox's death but had been "very straightforward" with the group about the limits of its technology, pointing to an email to a group representative that said, "there is no effective way to prevent [an] ambush attack."

After researching the product herself, Carey said she understood the band offered little protection against the kind of ambush attack she feared most at Lover's Point. She wore it anyway when she swam with Fox and the group that morning.

"I've never gone into the water consciously saying to myself, 'I don't need to worry about sharks, because I have this band on,'" Carey said. "So why do I wear it? That's a really good question, isn't it?"

You may read more about the 2018 study in our March 2019 issue of Undercurrent by clicking here.

This is a version of the original article written by Ryan Macasero and Julia Prodis Sulek, for Bay Area News Group: January 3, 2026, and other sources.