In the months following a flurry of shark attacks on Maui, anti-shark devices on the Valley Isle have been flying off the shelves. "We're having trouble keeping them in stock," said Dennis O’Donnell, owner of Hawaiian Island Surf and Sport, who has kept a waiting list on the product since December. "Because we had so many shark-related incidents here last year, the demand for these products has really sky-rocketed. We have a list of more than two dozen people waiting for them."
When it comes to shark attacks in Hawaii, Maui has borne the brunt of the blow (eight of the 14 statewide attacks occurred there) creating the surge in demand for a product that could protect surfers and beachgoers. The most popular anti-shark devices, which come in a variety of sizes and range in price points, typically retail between $400 and $700. O'Donnell's shop carries two different products, the ESDS, which is based in Hawaii and Shark Shield, a company based out of Australia. Both products operate under the theory that electromagnetic fields can deter sharks.
The premise behind the devices is relatively simple: All sharks have small, gel-filled sacs called the Ampullae of Lorenzini, which are located in their snout and can sense electrical current emitted from prey. Both the ESDS and the Shark Shield produce an electrical field that, from Shark Shield's website, "cause the shark to experience muscle spasms and a high level of discomfort, which causes it to turn away from the electronic field, effectively repelling the shark and protecting the user." Shark Shield, the older of the two products, originally created the product for divers and included a braid-like chord that produced the electromagnetic field. In recent years, they (along with ESDS) have created a product that wraps around your ankle, similar to a leash, designed specifically for surfers.
But do these devices actually work?
The maker's of Shark Shield point to multiple research studies and testimonials that back the science behind their product. However, some shark experts remain unconvinced that the devices comprehensively deter shark attacks. Dr. Carl Meyer, of the University of Hawaii's Shark Research Center, is one of them.
"There are a variety of anti-shark products out there. Some have a theoretical base and some are just nonsense. The devices based on electromagnetism [like the Shark Shield] have some potential. But I'm hesitant to say that they're completely effective. I still believe that there needs to be more exhaustive, independent research done before we can come to any concrete conclusion."
In a 2012 study conducted by Flanders University and the South Australian Research and Development Institute (SARDI), researchers tested Shark Shield's Freedom 7 device, which is typically wrapped around the ankle of the user and trails an antenna that distributes an electronic pulse. The study found mixed results that leaned on the positive side, with researchers concluding that the shark shield did indeed have an effect on shark behavior (it took the sharks longer to take the bait and deterred many of sharks from taking the bait at all) but "it did not deter or repel them in all situations nor did it repel all individual sharks."
When questioned by the Cape Argus, a South African news site, Dr. Alison Kock, who was involved with the study, said that "The combined results of the study indicate that while the risk of an attack may be reduced wearing a shark shield, the shields failed to repel great whites in all cases."
While not concrete, the studies conducted seem to show that anti-shark devices like the Shark Shield do indeed work to some effect. “We believe the SARDI research as very positive, most people don't read the whole report and often only report on half the results,” said Shark Shield’s Lindsay Lyon. Shark Shield has posted a series of YouTube videos explaining the positive notes from the research. While very confident in the effectiveness of their product, they were also quick to point out that the device isn’t a full-proof solution, but a deterrent: “Electronic shark deterrents are a safety device and there isn’t a single safety device that can guarantee your safety. People die wearing seat belts and safety helmets…”
Dennis O'Donnell of Hawaiian Island Surf and Sport, the store with the waiting list to purchase the devise, echoes this sentiment. "Whenever we sell an anti-shark device in our shop, we'll give the customer as much information as possible and let them make the decision. We let them know that they've been proven to be effective, but they're not going to provide you with a guarantee against being bit. But at the end of the day, the ocean's not Disneyland. There's always going to be risk. And the best thing you can do is to be smart about when and where you're surfing. That's the biggest deterrent."