Sydney, Australia - The terrifying - albeit infinitesimal - prospect of being attacked by a shark played harder than usual on the minds of many of the 20,000 locals and tourists who flocked to Sydney's world-famous Bondi Beach recently after the carcasses of two great white sharks were found in nets 500 metres offshore.

So it must have seemed like a scene from Steven Spielberg's 1975 thriller Jaws when the shark alarm sounded across Bondi after a great white swam so close to the shore its protruding dorsal fin was clearly visible from the beach.

"We were all here training at about 2:45pm when we heard this really piercing scream and realised it was the shark alarm," says Marcus Bondi, a personal trainer who works at Bondi's outdoor gym. "The lifesavers were calling out on the megaphones 'Shark! Shark! Get out of the water!' So everyone ran out and was standing near the edge with their cameras out."

Adds lifeguard Grant Sassall: "The ocean is full of sharks. When I go ski paddling, I see them all the time."

The recent sightings have raised shark anxiety in Australia and concern of a repeat of 2009's "summer of sharks". The period saw three unprovoked shark attacks within 24 hours and another two in Sydney within the space of a few days, including one at Bondi Beach that resulted in the amputation of a surfer's hand. 


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However, Martin Garwood, the senior aquarist at Sydney Sealife Aquarium, said last week's incidents at Bondi are not indicative of a spike in shark numbers.

"Right now there are large schools of salmon and kingfish running up Australia's east coast, so it's the natural behaviour of predators like sharks to follow these fish around. Last week, we also had a pod of more than 100 dolphins at Malabar a few kilometres south of Bondi."

He added, "The only reason these shark sightings are attracting so much public interest is because Bondi is such a big tourist attraction."

Sydney University lecturer in public policy Christopher Neff concurs.

"Like any beach, Bondi has a steady stream of sharks and if they're netted, some will inevitably get caught. The only thing that has changed is that the public is paying closer attention for several reasons. The first is the heat - it's not usually 45°C in November - so with more people going to the beach there are more shark stories," Neff said.

"The second is the two shark fatalities in the state [of New South Wales] this year and the third is the abnormal number of sharks being caught in nets. All those create greater consciousness about sharks, but that doesn't mean there are more sharks at our beaches." 

No one wants to see dead marine life, full stop. But there has to be consideration for the safety of swimmers.

- New South Wales state Premier Mike Baird

Despite their seemingly positive contribution to public safety, debate is raging in Australia about the efficacy of nets and other fatal shark-bite mitigation tools like Western Australia's drum lines (baited hooks attached to flotation devices) that kill great whites and other endangered and protected shark species.

As the incidents in Bondi showed, the nets do catch and kill potentially dangerous sharks.

A spokesperson for the New South Wales' Department of Fisheries told Al Jazeera the state's shark-meshing programme has provided "a safer environment for swimmers and surfers since it was first introduced in 1937", and "protects around two million people who swim at these beaches each year".

"They are designed to deter sharks from establishing territories, thereby reducing the odds of a shark encounter," she said anonymously, as is state government policy.

Sydney University's Neff begs to differ.

"There is no scientific evidence that can credibly assert that nets reduce the risk of shark bites. That line used by the Department of Fisheries that nets deplete shark populations is simply not true. Sharks don't establish territories, there is no science to support that claim at all, especially not with great white sharks."

Sydney Aquarium's Garwood voices similar sentiments.

"We know that sharks never stay at one food source. They just follow food wherever it goes. So the department's claim that nets make the beaches safer is not really the case. All nets do is kill certain animals. It is more of a mental safety blanket for swimmers than anything else. It is quite an outdated technology."

Surfers head to the waves on Sydney's Bondi Beach [Reuters]

Another problem with shark nets is they are indiscriminate killers that catch a large number of whales, dolphins, turtles and thousands of other harmless species of marine life.

"The argument of killing an animal to survive for food is a thing that most people can accept," said Sharnie Connel, an animal keeper at Manly Sealife Sanctuary and spokesperson for No NSW Shark Cull.

"But it's a stretch to say we need to kill an animal so we can have fun in the water. The simple fact is the ocean is not a giant swimming pool and it's not necessary for our survival to be recreating in the ocean."

Connel noted there are various non-lethal shark-bite mitigation tools like the Eco Shark Barrier, which forms a harmless solid barrier around swimmers: the Shark Safe Barrier project from South Africa, which uses electromagnetic pulses to deter sharks; and the Clever Buoy prototype, which uses sonar and GPS technology to warn beach-goers about sharks.

In July, Manly Council voted for an investigation into non-lethal shark deterrents, with Mayor Jean Hay saying beach-goers have a far greater chance of being hit by a car than being bitten by a shark.

New South Wales state Premier Mike Baird, who once had a face-to-face encounter with an aggressive shark while surfing and only narrowly escaped without injury, is also backing the trials. But he maintains the safety of beach-goers is paramount over bycatch concerns and that nets will remain in place until a viable alternative is found.

"No one wants to see dead marine life, full stop," he says. "But there has to be consideration for the safety of swimmers." 

Source: Al Jazeera