Undetected on the mountain slope, Tino Simmerie sweeps his binoculars over the South African bay where bathers happily splash about in turquoise waters.

"They don't have a clue what's going on basically," he said, staring out at the popular Fish Hoek beach where he once saw a shark come up to the shore.

"We never know for sure when a shark is going to come into this bay -- that's why we're every day up here to just keep an eye out."

Armed with a walkie-talkie, binoculars and polarised sunglasses to protect against the harsh ocean glare, the 22-year-old is part of Cape Town's frontline with the Great Whites sharing its seas.

The pioneering programme, Shark Spotters, started in 2004 after a spate of bites and sightings by placing human look-outs at busy beachers to give the alert for the sea to be cleared if fins are seen moving in.

South Africa records fewer attacks than other shark international hotspots like Australia and the United States.

But the fatality rate is high: South Africa accounts for one-third of the 24 deaths worldwide on the International Shark Attack File for the past three years, despite local bites making up less than 10 percent of all attacks.

The latest victim was a young Cape Town bodyboarder who died on April 19 after his leg was bitten off at a remote surfing spot, which followed a near-fatal mauling in September across the bay at top swimming site Fish Hoek.

Attacks in the age of Twitter have sparked alerts of "dinosaur huge" killers -- as tweeted by a witness to a 2010 death on Fish Hoek -- and fierce debate over theories of why bites are on the increase.

"You can understand, it's a very emotional issue especially for the people who have witnessed shark attacks," said Sarah Titley, Shark Spotters project manager.

"Being eaten by a very large fish is a very scary unknown that makes people react in a completely disproportionate way to what the actual sense of risk is. You've got a one in 253 million chance of being killed by a shark."

"So the risk is very small but it's such a traumatic event for people and it really does cause a lot of hype and hysteria."

-- 'Don't want to kill the sharks' --

To counter some of the fears, an exclusion net is on the cards for Fish Hoek, to add another layer to the city's prevention buffers after the attack seven months ago deepened its deadly reputation on the back of two deaths since 2004.

"It's a series of fixed nets which are very small diameter mesh so that nothing can swim through it," said Cape Town alderman Felicity Purchase.

"We needed to find something that would be practical, that would not cause damage -- we don't want to kill the sharks, we don't want to damage the other marine life that comes through."

Shark nets are controversial and were ruled out years ago, but officials say they need to tackle the damaging economic fall-out and that the square-inch sized mesh technology is successfully used in Hong Kong and the Seychelles.

"This will provide a safe area for parents who are worried about their children particularly, and for the elderly who are not so fast getting out of the water," said Purchase, saying two nets will cost 750,000 rand ($93,000, 73,000 euros).

"This will certainly prevent shark attacks in an area which allows considerable swimming space for our bathers. So I believe it could actually be the end of shark attacks."

Reaching up to six metres (20 feet) in length and two tonnes in weight, Great Whites are protected in South Africa and listed as vulnerable on the IUCN Red List of Threatened Species.

They regularly prowl inshore during summer while tracking game fish and have a key winter feeding site of Seal Island in the giant False Bay which is a global Great White hotspot.

The city therefore accepts that attacks are inevitable with a population of 3.5 million people sharing its 307 kilometres of beautiful coastline.

Spotters are on permanent watch at four beaches, and at six during summer, using a simple but effective system of flags and sirens between the look-out and a beach-based controller that beach-goers depend on -- even if unknowingly.

Not everyone listens to the spotters. A British man lost part of his legs last year after ignoring the Fish Hoek beach's closure.

Despite the increased sightings and attacks, the experts say no rogue man-eater with a taste for human flesh is lurking about Cape Town's seas, where more nutritious prey swim.

"Since the programme began in 2004, we've had over 1,200 shark sightings," said Titley.

"People report sharks just swimming straight past them, so if sharks really did want to eat people, we'd be suffering a lot more attacks that what we do," she added.