The Latest Tech for Sharkproofing Beaches

Next month marks 100 years since the Jersey Shore shark attacks. A rogue shark (or multiple sharks, depending on which scientist you ask) killed four people and injured one during a two week span in early July 1916, at a time when a brutal heat wave and polio epidemic were driving thousands to resorts on the Atlantic coast. The attacks not only spurred panic and shark eradications on a national scale, they also immediately redefined the shark’s image from one of a timid sea creature to “the incarnation of ferocity.” Shark fever swept the nation, and soon newspaper cartoonists were using sharks to lampoon topics as diverse as German U-boats and prudish Victorian bathing suits.

Today, of course, ichthyologists know the truth about sharks and their behavior: they have lots of sharp teeth and occasionally attack without provocation. The popularity of films like Jaws and the annual sharkathon Shark Week, which kicks off June 25th this year, confirms that the mystique is still in vogue a century after the New Jersey incidents. While fatal shark attacks draw heavy media attention, they’re quite rare, with less than 100 total attacks reported each year. Still, those with a stake in beaches and resorts use a variety of technologies to prevent attacks.

A simple strategy for preventing attacks is to detect a shark’s presence and warn beachgoers to get the heck out of the water. In Cape Cod, Massachusetts, where a burgeoning seal population is drawing record numbers of great whites closer to shore, municipalities are posting traditional signage as well as large, dramatic billboards showing scary-looking sharks. For people whose heads are permanently looking down at their phones even at the beach, local group Atlantic Great White Conservancy is launching an app to allow visitors to track tagged great whites or quickly report seeing untagged ones. This year Cape Cod and other locales on the Eastern Seaboard may begin using drones to monitor shark populations close to shore. California and Australia already engage in drone monitoring, but the murky East Coast waters make visual sightings a challenge.

The other angle is to repel sharks from heavily populated beaches altogether. Traditionally, drum lines and shark nets were used for this purpose, but these methods endanger other non-harmful species, including non-aggressive sharks. South Africa’s KwaZulu Sharks Board is currently commercializing a shark-deterrent cable they tested in 2014. The cable features vertical “risers” that emit a low-frequency signal designed to confuse the shark’s sensory system. A shark’s nose contains an electroreceptive organ called the ampullae of Lorenzini that detects the potential difference between the voltage at the base of the electroreceptor and the voltage at the shark’s skin. The ampullae allow the shark to detect a far-off living creature’s heartbeat through the water, assisting with hunting and tracking. If successful the cable would be a huge improvement over shark nets: sharks have the greatest electrical sensitivity of any known animal, so the small electric fields won’t bother any other sea life or nearby humans. According to the Shark Board, the cable’s current is so small that a person accidentally contacting the cable would feel little more than a tingle.

Shark attacks are rare, but as evidenced by the recent Orlando alligator incident, most vacationers aren’t attuned to keeping their eyes peeled for local wildlife hazards. Development of sharkproof tech seems to benefit all involved, from the beachside communities who lose business at the first sign of a fin to the tourists who depend of them to stay safe.

Image credit: KwaZulu Natal Sharks Board