Shark Shocker : Electric Device Repels Predators, but It’s Safe for Divers

Jim Morris was about to give new meaning to the idea of swimming with the sharks as he prepared to plop into the waters off Catalina Island.

Swaddled from head to toe in a wetsuit, he slipped on his flippers, strapped on a steel aqua lung and grabbed a small device that attaches to the back of an air tank and a fin: an electronic shark repellent.

Aboard the 64-foot vessel the Pacific Explorer, the Marina del Rey distributor was testing the small apparatus Tuesday to see if its electronic field would keep away blue sharks, whose razor-sharp teeth have been known to bite into a diver or two.

As he swam under the water, a curious 5-foot shark sped toward Morris to check him out. Then, as it neared the electrical field around him, it quickly darted away.

Developed by the Natal Sharks Board, a respected scientific agency run by a South African province, the shark repellent known as Shark POD is about to be released to West Coast dive shops and sporting good stores once the product liability insurance is worked out, Morris said. It will retail for about $800.

California experts laud the device’s technology, saying sharks are effectively deterred by electromagnetic fields because their snouts detect electrical signals.

Other electronic devices have been developed over the years, but their voltage was so strong that the diver got just as much of a shock as the fish, said Peter Klimley, a marine behaviorist with UC Davis.

The new device, however, is powered with a battery that is no stronger than the one in the average flashlight.

Marine scientists still harbor one concern. They wonder if the electronic field is strong enough to offset a great white shark zooming in at top speed from the bottom of the sea.

That, Morris admitted, is something he would like to confirm himself even though five years of testing off the coasts of South Africa and Australia show that the device is effective against great white sharks.

California does not have the same shark problem as places such as South Africa or Australia, experts said. Since 1950, there have been 105 shark attacks, eight of them fatal, along the Pacific Coast from California to Washington, said Ralph S. Collier, a Canoga Park insurance broker who since 1959 has tracked shark attacks in the area.

Southern California is one of the safer places to dive and surf, he said. Marine behaviorists say that of the three shark species most dangerous to humans, the tiger and the bull shark are never in Southern California waters and the great white is found only occasionally.

Most California shark attacks occur farther north, near Santa Barbara and San Miguel islands and the Farallon Islands. Both areas are near entrances to pinniped rookeries. Great white sharks love to feast on young seals and sea lions.

“I feel very vulnerable when I’m on the bottom of the ocean,” said Steve Larson, who manages a dive shop in Santa Cruz and plans to stock the device.

Larson was diving with a buddy last year near Point Conception north of Santa Barbara when his friend was attacked by a great white shark. He survived the attack.

Two great white attacks occurred near Point Reyes in Marin County this summer and fall. Both victims--a diver and a surfer--lived.

The last known death from a shark attack in the state occurred two years ago near San Miguel Island when commercial sea urchin diver James Robinson, 42, was killed by a great white while treading water near his boat.

Mark Hamerdinger, a commercial diver who knew Robinson and works in the waters around San Miguel Island, said he is eager to use the shark repellent when it goes on the market. He has been helping Morris with local tests of the device.

Right now, Hamerdinger, who dives 125 days a year but has never been attacked by a shark, has a haphazard method for protecting himself. He straps pieces of plastic around his thighs and puts soap or detergent in his wetsuit. For some reason, sharks are repelled by the surfactant in cleaning products. But he would like something more effective.

“The sharks are so fast,” he said. “A diver is like a snail in the water.”

The Shark POD for divers works this way: A small plastic unit powered by a rechargeable battery lasting 90 minutes is attached to an air tank. Another unit is strapped to one fin. The two units are connected by a cable. When activated by a control switch, an invisible electrical field is formed, repelling sharks that are 12 to 21 feet away in any direction.

South Africa has had major problems with shark attacks on its beaches and over the years it has fashioned various ways to keep the sharks out of local waters. In Durban, a coastal city of Natal, officials installed thick nets in the waters around the beaches, but a variety of marine life and sharks were killed. Another type of net was devised that allows smaller fish through but not sharks.

But their dream, said Graham Wynne of the Natal Sharks Board, is to set up some kind of electronic apparatus in the ocean that would ward off sharks approaching the area. The individual shark repellent device is just the beginning.

The board is also working on shark-repellent surfboards and kayaks. One day there could even be a shark-repellent belt you strap around your swimsuit.

“This device will be able to help people who are petrified of the ocean,” Morris said. “More people can interact with the marine ecosystem.”