''Swimmers are in the way, not on the menu,'' he said. ''There is no evidence any shark species develops a taste for human flesh.''

Mr Neff does not want to downplay the tragedy of serious or fatal encounters with these apex predators of the sea, particularly during this summer of heavy rain, when swimmers will have to be extra careful about where and when they take a dip.

''Shark bites are scary,'' he said. But persistent myths and sensationalism can lead to ineffective, political solutions, such as the recent authorisation of a shark hunt in Western Australia after three deaths, which would have made no swimmer safer if it had gone ahead, he said.

Rather, straight talking and good information is needed, such as the facts that shark numbers increase in summer in Parramatta River and Sydney Harbour, and people shouldn't swim there for three days after heavy rain because sewage attracts sharks.

''Then people can determine their own level of risk, based on their behaviour.''

Mr Neff, an American, said it was wrong for incidents always to be described as attacks, when bites are often defensive or done out of curiosity.

''The public is unable to tell scratches from fatalities, boats from people, or wobbegongs from great whites,'' he said.

About 13 per cent of so-called shark attacks in NSW are by wobbegongs, for example. ''That means someone was stepping on it or pestering it.''

Mr Neff has been fascinated by sharks from childhood. His first research project in Sydney was on conservation of a different carnivore, lions, which provided a telling comparison.

Unlike with the ocean, people easily recognise that the African bush is the wild, and it is unwise to wander alone when and where lions feed, he said.

Before the ''rogue shark'' concept was developed, shark attacks were often referred to as ''shark accidents''.

And after some fatalities in the 1920s, a NSW government committee nevertheless concluded ''sharks do not patrol the beaches on the off-chance of occasionally devouring human prey''.

But the Sydney notion of rogue sharks, made internationally famous in the movie Jaws, has persisted, Mr Neff said. ''And now we see it in a policy response in 2011 [with the proposed hunt].''

As someone who has seen great white sharks attack seals in South Africa, he said sharks do not set out to eat people, because humans provide low nutrition.

If sharks wanted to attack people, there would be many more bites, given the increasing numbers of swimmers.

Amy Smoothey, a shark researcher with the NSW Department of Primary Industries, said that on Australia Day last year there were seven tagged mature bull sharks in Sydney Harbour, sharing the waters with thousands of people, including those in a harbour swim event.

Yet there were no incidents or reported sightings. ''The misconception is that all sharks are out to hunt us. But this provides evidence that sharks and humans can co-exist,'' Dr Smoothey said.

Her tagging research is aimed at providing the public with more information about where the bull sharks are most likely to be.

That sharks visit the harbour indicates it is a healthy waterway. ''We should be grateful for their presence,'' she said.

Sharks have killed one person a year in Australia, on average, for the past 50 years.

Surgeon came up with 'rogue' theory

The eminent Sydney surgeon, Sir Victor Coppleson, who worked with the Surf Life Saving Association and helped introduce mouth-to-mouth resuscitation, concluded in 1933 in the Medical Journal of Australia that the ''evidence sharks will attack man is complete''.

He developed the theory of a rogue shark, which ignores its natural prey for people, and published a book, Shark Attack, in 1958.

The first New Orleans Shark Symposium in 1958 cemented ''attack'' language in the scientific community.

In 1974, Peter Benchley wrote Jaws and Steven Spielberg, in 1975, turned it into a blockbuster film.

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