Three shark attacks in Australia in two days this week sparked a global media frenzy of "Jaws" proportions, but sharks are more at risk in the ocean than humans with man killing millions of sharks each year.Sharks are the top of the marine food chain, a powerful predator which has no match in its watery realm, until man enters the ocean.Commercial fishing and a desire for Asian shark fin soup sees up to 100 million sharks, even protected endangered species of sharks, slaughtered around the world each year, says the Shark Research Institute (Australia).Yet in contrast, sharks, apparently, do not like the taste of humans. Very few shark attacks involve the shark actually eating the human, unlike a land-based predator like a lion or tiger."Most of the incidents in the (Florida-based) global shark attack file have nothing to do with predation," says the Institute on its website (www.auscyber.net).Unlike fat seals -- the preferred meal of sharks like the Great White -- humans are bony with not much fat. Sharks use various sensors to hunt their prey and a quick bite will tell it whether its found a good meal.Usually when a shark bites a human it then swims off. Unfortunately for humans, sharks are big and we are small, so a large shark bite can mean death from rapid loss of blood."Sharks are opportunistic feeders. They hear us in the water, we sound like a thrashing fish or animal in the water, and they just react to that instinctively and go to take a bite," marine analyst Greg Pickering told local radio on Wednesday.According to the latest figures by the International Shark Attack File, there was only one fatal shark attack in 2007. It took place in New Caledonia in the South Pacific. The mean number of deaths between 2000 and 2007 was 5 a year."You have more chance of being killed driving to the beach," said John West, curator of the Australian Shark Attack File at Sydney's Taronga Zoo.In fact, the number of fatal attacks around the world has been falling during the 20th century, due to advances in beach safety, medical treatment and public awareness of shark habitats.The bulk of shark attacks do not happen in Australian waters, despite its shark reputation, but in North American waters. Half of the world's shark attacks occur in the United States, and one third of the world's attacks are in Florida waters.In 2007, there were 50 shark attacks in U.S. waters, compared with 13 in Australia in the same year -- none were fatal.The big difference between Florida and Australia is that the later has much bigger sharks and therefore more fatal attacks. From 1990 to 2007, Australia had 19 fatal attacks, Florida 4.But there have only been a total of 56 fatal shark attacks in Australia in the past 50 years, or an average of about 1 a year, says the Australian Shark Attack File.The last fatal attack occurred in December 2008, when a Great White attacked a 51-year-old man while he was snorkeling off a beach south of Perth in Western Australia.So, is it safe to go back in the water?Shark attacks are on the rise worldwide, but according to the International Shark Attack File, that doesn't mean there is an increased rate of shark attacks. "As the world population continues its upsurge and interest in aquatic recreation concurrently rises, we realistically should expect increases in the number of shark attacks," says the file on its website (www.flmnh.ufl.edu). SHARKS IN DECLINE But while more humans enter the ocean each year and for longer periods of time, the shark population is declining, theoretically reducing the chances of a shark-human encounter. "As a result, short-term trends in the number of shark attacks, up or down, must be viewed with caution," says the file. So, if shark numbers are falling why are there more sightings of sharks off Australia's beaches. Surfwatch Australia, which conducts aerial patrols of Sydney beaches, estimates shark sightings have risen 50 to 80 percent in recent years. Wildlife officials say cleaner beach water means sharks are chasing food closer to shore. Sydney beaches were closed this month when hammerheads started feeding on squid near swimmers. But only about two dozen shark species are considered potentially dangerous to humans because of their size and teeth. The Great White, Bull, Tiger and Hammerhead are among the most aggressive and responsible for most attacks in Australia. The Great White can grow to 5.5 meters (15 feet) in length, weigh up to 1,000kg and has the biting power to lift a car. Australian scientists have recorded the bite power of a 3.2 meter (10 foot) shark as equivalent to 1.5 tonnes of pressure. The aggressive looking Grey Nurse, with its piercing eyes, pointy nose and protruding teeth, is as timid as a cat and will only attack if provoked. But its fierce appearance has seen it hunted to the point where it is now endangered and colonies of Grey Nurse sharks off Sydney are protected. There are 30 sharks, including the Great White, on the International Union for Conservation of Nature's threatened species list. "Sharks need our help now and we cannot let our fear push them to the brink of extinction," says Ben Birt, from Australia's Nature Conservation Council, which has launched a "Save Our Last Sharks" campaign.