Just when you thought it was safe ...

<preform>In South Africa, all that's left of a swimmer is a little red bathing cap. In New Zealand dolphins come to the rescue. The Great White is back, but this time the fish is in danger. Steve Connor </b></i>reports</preform>

It is every swimmer's nightmare. You find yourself alone some way out from the beach when a dark, menacing shadow passes through the water a few feet away. Seconds later a gaping mouth full of razor-sharp teeth lunges at you.

It is every swimmer's nightmare. You find yourself alone some way out from the beach when a dark, menacing shadow passes through the water a few feet away. Seconds later a gaping mouth full of razor-sharp teeth lunges at you.

Most people who experience a shark attack survive the encounter but Tyna Webb was not so lucky. Earlier this month, the fit and healthy 77-year-old South African disappeared after a great white shark attacked her off a Cape Town beach.

Mrs Webb had been taking her regular early morning dip in the sea when the shark was seen circling her three times before dragging her under the water. Witnesses said that the only thing left was her red swimming cap.

A group of lifeguards training in New Zealand had a luckier escape. They reported this week that a pod of dolphins had come to their aid when they found themselves being investigated by a shark.

Ron Howes was on a training swim with his 15-year-old daughter and two of her friends. He realised that something was wrong when bottlenose dolphins suddenly began herding the swimmers together and circling protectively around them.

When Mr Howes broke out of the circle, two of the larger dolphins tried to coral him back in. He needed little encouragement when he saw a great white shark coming his way.

"I just recoiled. It was only about two metres away from me, the water was crystal clear and it was as clear as the nose on my face," Mr Howes said.

Marine biologists believe the dolphins - air-breathing mammals the same as humans - were probably applying a natural defensive posture that they use to protect themselves and their young from predators.

Eye-witness accounts of shark attacks bear testimony to the fear they can generate. Dunstan Hogan, 49, was surfing off the coast of Cape St Francis in South Africa in April 2001 when he was nearly killed.

"The attack came without warning. I was lying on my surfboard when I saw this grey mass and thrashing tail fin approach. And suddenly I felt this enormous pressure, like being gripped in a vice," Mr Hogan later recalled.

"The shark wrapped its teeth in a half moon over my left thigh, buttock and hip, along with the underside of the surfboard.

"It lifted the board and me clear of the water. It then released me before biting into me again, getting the back of the board again too, and dragging me several feet under water," he said.

"There was a lot of turbulence in the water, with sand churning up all over the place. I just couldn't see where the shark had gone. I pulled the surfboard towards me again and mounted it to exit the area as quickly as I could," he said.

Thanks to emergency medical treatment, Mr Hogan survived the shark encounter, as did Rodney Fox, an Australian spear-fishing champion who in 1963 survived probably the worst non-lethal shark attack in history.

"I looked down and saw that great big jaw rising at me through a cloud of my own blood and I knew I was is in trouble," Mr Fox said later.

His wetsuit kept his insides from spilling out - he needed 462 stitches. By a miracle, he survived.

Perhaps rather surprisingly, Mr Fox holds no grudges and even campaigns for the protection of great white sharks. "He was only doing what sharks do," he said.

The fascination with shark attacks has for decades caught the public imagination. It has reached a crecendo once again. From Peter Benchley's 1974 novel Jaws to this summer's block-buster movie, Open Water, based on a true story of two divers stranded in a shark-infested ocean, the Great White has fascinated and terrified us.

Understandably, every attack, especially lethal ones, receive huge publicity. And with more and more people taking holidays in exotic beach locations, it is easy to get the impression that shark attack are on the increase for more than the simple reason of more swimmers.

But Professor George Burgess, director of the International Shark Attack File at the University of Florida in Orlando, believes that the wide publicity given to attacks leaves people with a false sense of the real risk.

In 2001, for instance, there was a wave of newspaper and television reports about shark attacks, and Professor Burgess said that he fielded thousands of telephone calls from both the press and members of the public.

Yet when he looked at the figures at the end of the year, the number of shark attacks and deaths across the world was in fact slightly down on previous years. In any typical year no more than a handful of people die as a result of a shark attack.

In America, you are hundreds of times more likely to be killed by a stray deer on the road than by a shark, Professor Burgess said.

"It's all about relative risk. Shark attacks are very uncommon compared to everything else, but sharks have a reputation," he said.

"It's also about control. We can stop the biggest land predators with a bullet but one-on-one in the water, we're no match for a shark," he explained.

In trying to explain why sharks and other large predators capture our imagination, Benchley is fond of quoting the great evolutionary biologist Edward O Wilson who argues that even fear has a place in biology.

"We're not just afraid of predators," Wilson once wrote. "We're transfixed by them, prone to weave stories and chatter endlessly about them, because fascination creates preparedness, and preparedness, survival. In a deeply tribal sense, we love our monsters."

For a man who has made millions out of demonising the great white shark, Benchley's love of his monster has come full circle. He now devotes much of his time calling for its conservation in the wild.

"One thing, I do know: the knowledge we have accumulated about great whites in the past 25 years has convinced me that I couldn't possibly write Jaws today ... not in good conscience anyway," Benchley said.

"Back then it was generally accepted that great whites were anthropophagous (ie they ate people) by choice. Now we know that almost every attack on a human is an accident: the shark mistakes the human for its normal prey," Benchley explained.

"Back then, we thought that once a great white scented blood, it launched a feeding frenzy that inevitably led to death. Now we know that nearly three quarters of all bite victims survive, perhaps because the shark recognises that it has made a mistake and doesn't return for a second bite," he said.

In short, it may have been alright to demonise the animal in 1974 when we knew no better, but today the great white shark - along with many other members of the group of skates, rays and sharks - is so seriously endangered that it must be understood rather than feared.

Professor Burgess explained that this is the real story that everyone should be reading about. "It's not about shark bites man, it's about man biting shark," he said.

The life story of the great white is something of a mystery. As WWF, the World Wide Fund For Nature (formerly the World Wildlife Fund) says: "No-one knows how many great whites there are: indeed we cannot make even an educated guess. Within their known extensive range, great white sharks seem to show up wherever and whenever it suits them - sometimes singly, other times in pairs or occasionally in larger numbers."

Although nobody has been able to carry out a global census of the great white, marine biologists report that in some "core areas" numbers have apparently fallen in recent decades by between 65 and 95 per cent.

The great white has adapted over millions of years of evolution for survival as a top predator in the marine food chain. It can grow up to 6 metres (19.6ft) long and weighs as much as 3,000 kilograms (3 tons).

Satellite tags on great whites in the wild show they can travel huge distances. One such tagged shark roamed 2,946km (1,830 miles) in 129 days, cruising at speeds of between 1.2 and 3.3km an hour, mostly within site of a shoreline.

But what makes the great white, and other members of the shark family, so vulnerable is that they take 10 to 16 years to reach sexual maturity. Secondly, they give birth to a handful of live young - unlike most fish, which can produce thousands of eggs each breeding season.

"Sharks are superbly adapted as predators but they have an Achilles' heel. They are slow growing and slow to reach sexual maturity," Professor Burgess said.

With no natural enemies, apart from killer whales, great whites are nicely tuned for a life at the top of the food chain - which entails a slow rate of reproduction. But with fishing and trophy hunting, this biological trait has turned into a serious disadvantage. One consequence is that their numbers have taken a nosedive.

Last month, concerns over the survival of the great white shark led to the World Conservation Union imposing strict controls on the international trade in its teeth and jaws - a measure opposed by Norway, China and Japan.

Sonja Fordham, a shark-conservation specialist for The Ocean Conservancy, said the controls were vital to ensure the survival of the species. "Despite their high profile, the great white is one of the world's rarest sharks. Their small populations and low reproductive capacity leave them ill-equipped to withstand heavy fishing pressure," she said.

It may be hard to believe that a creature that is so perfectly adapted to its environment, one that, as Benchley once remarked, swims with "the confidence of the invincible", has turned out to be so vulnerable.

So the next time you read a book or see a film about the predatory horrors of the deep, have a thought for what life is like for the shark. "When we get down to it, we're much more worried about us killing them than them killing us," explained Professor Burgess.

"What we need to remember is that when we enter the sea, it doesn't belong to use. It belongs to the creatures that live there," he said.

As Benchley once said: "Great white sharks have survived, virtually unchanged, for millions of years. They are highly evolved, as perfectly in tune with their environment as any living thing on the planet. For them to be driven to extinction by man, a relative newcomer, would be more than an ecological tragedy; it would be a moral travesty."

HOW SAFE IS IT ON THE BEACH?

¿ About four or five people a year die on average from shark attacks worldwide.

¿ There have been about 100 deaths reported worldwide over the past century. More people have died in recent decades because more people are taking holidays on coasts where sharks live.

¿ Between 1990 and 1999 there were 530 shark attack worldwide and 71 of these were fatal.

¿ The worst year was 1993 when 14 people died in 55 attacks. The best year was 1991 when two people died in 37 attacks.

¿ The chances of drowning in a beach-related accident is about one in 2 million. The chances of being attacked by a shark is about one in 12 million. The chances of being killed by a shark in an area where they live is greater than one in 264 million.

¿ Average number of deaths due to collision with a deer on the road in the US is 130 per year. The average number of deaths due to shark attacks is 0.4 per year.

¿ On average about 15 people at year die in the US as a result of snake bites, 18 Americans die from dog attacks and an average of 0.6 from attacks by mountain lions - slightly greater than the risk of being killed by a shark.