DANGEROUS SHARKS FACE HIGH-TECH OPPOSITION.

Byline: Shawn M. Bush Special to the Daily News

As the Pacific Explorer pulled away from her San Pedro slip, a cage normally used for shark expeditions remained tethered to the dock.

``From what I understand, they won't be needing that,'' said Rick Lawson, leader of the hunt. ``That's what worries me.''

Whether foreshadowing a future where the cage will become obsolete or one where the divers wished they had brought it along remained to be seen. The cage has been one of the most reliable methods for interacting with dangerous sharks in the wild . . . until now.

Those gathered aboard the 64-foot boat did not glance back. Instead, their eyes were cast into the cold fog that shrouded their mission - testing a high-tech device designed to drive sharks away from divers by keeping them surrounded in a cocoon of electrical energy.

It was to be the second time veteran diver Jim Morris, the distributor of Shark POD, tested the unit on blue sharks. He hoped for something with a bigger bite, namely the mako.

As they sipped coffee, the divers swapped stories of encounters with the carnivorous denizens.

For Santa Barbara sea-urchin diver Mark Hamerdinger, one of the stories struck particularly close to home. He had been friends with fellow urchin gatherer James Robinson, who was killed by a great white in December 1994 after surfacing from a dive off San Miguel Island - the last known shark-attack fatality in the state.

``That area is commonly referred to as shark park,'' said Hamerdinger, who took only a few days off after the death of Robinson before returning to his livelihood under water. ``Just 'cause I'm scared doesn't mean I stop diving. You still get in the water, even though you know there are sharks (around). It is just something you live with.''

Morris claims Shark POD - ``protective oceanic device'' - could change the way people feel about ocean diving.

The device was developed by the South African agency Natal Sharks Board in response to a serious problem with great white attacks. It emits an electrical current of low frequency that is undetectable to man but irritating to sharks. When they swim within 12 to 21 feet of the diver, the signal is detected and the shark flees. It has shown no ill effects on other creatures.

At Avalon Banks, a ridge at a depth of 1,500 feet in the 3,000-foot San Pedro Channel, the process of baiting the water began. A pungent brew of fish entrails and blood was slowly drained over the boat to create a chum slick aimed at attracting sharks from miles around.

Divers anxiously checked their gear. Morris, who was to conduct the test, attached the yellow box to his air tank and a flat electrode to his fin, which enables a current to flow between the two parts and create the safety ``cocoon.'' A battery with a lasting power of 90 minutes charges the unit.

At first, the sharks don't take to the chum. With hundreds of pounds of bait in the water, the question beckoned whether a shark repellent is necessary. Many don't think so.

``I've been diving for 37 years. It is rare we see a shark. I wouldn't be interested (in a repellent) because of my experience. I've never had an incident of any type,'' said San Pedro sport diver Roger Hess. ``The odds of an attack are a million to one.''

And the device is not without its critics.

Cal State Long Beach professor of marine biology Donald Nelson is testing the Shark POD.

``I don't know everything about the device but would question its safety as far as any negative effect on the diver. Cardiac fibrillation can result from exposure to electrical pulses,'' he said. (Previous devices had proved to be too shocking to the divers.)

Nelson also questioned the impact of a circling shark that makes repeated approaches on a diver armed with the device.

``Will it get used to the signal and ignore the device?'' he pondered. ``Of course, we're talking about a threat that is not very great to begin with.''

Shark POD was recently made available in Australia and has been on the South African market since July. Once insurance liability is established, it will be available in the United States for about $800, Morris said.

The technology has been tested for about five years on great white, tiger and bull sharks and proved effective in repelling them, according to Morris. And though Southern California is not plagued by great whites, as Northern California waters are, the predators are present during the seal and sea lion pupping seasons from September through December. Regionally, blues and makos are the most common sharks, both of which have been known to attack humans.

Within minutes of the decision to cancel a night dive because of rough seas, a Pacific Explorer crewman yelled, ``We have three six-footers. Three six-footers.''

The sharks circled the boat, their dorsal fins protruding from the frigid ocean. They proved to be blues, not makos, but Morris and the other divers readied their gear in an excited fervor just the same. An underwater camera would transmit their adventure to the boat.

Static-filled images flickered on the monitor as the divers plopped into the brine. The silhouette of a large blue shark filled the screen. The divers calmly treaded water as the animals circled them with curiosity. One of the sharks swam toward the camera lens, its black eye glancing from side to side. The cameraman bumped it, but the shark circled around for another glance.

Another approached Morris. It snaked forward with fluid elegance. The Shark POD was off, but Morris held tightly to its trigger as the blue closed in. Within two feet of Morris, the shark had not changed its course. Then Morris activated the device, and, instantly, the shark made a sharp U-turn and bolted out of view.

Morris repeated the test on another blue with the same results.

Back on the boat the test was considered a success. Hive-fives were exchanged as the divers climbed aboard.

Still, Morris was somewhat disappointed. The Marina del Rey distributor spoke about plans for the next test.

``I want to test this thing on the mako. That is a different animal,'' he said.

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Photo

Photo: Diver Steve Larson inspects a Shark POD unit, which is used to repel sharks.

Shawn M. Bush / Special to the Daily News