Shark attacks starts debate

In a life-and-death struggle, Australian surfer Jake Heron punched the great white shark as it bit his arm and thigh, turning the ocean into a bloody cauldron.

Miraculously, Heron, 40, lived to tell the tale.

Very few people survive an attack by a great white, which can grow to 20 feet, weigh 2.5 tonnes, and with enough power in its jaws to lift a car.

Two weeks earlier, marine biologist Jarrod Stehbens, 23, also fought a great white as it pulled him underwater as he tried to climb into a boat. Sadly, Stehbens lost his fight for life.

These two attacks in the past few weeks, both in waters off South Australia state, have sparked an emotional debate in Australia over whether the great white, the ocean's fiercest predator, should be culled.

Displaying his savaged surfboard, bitten in half by the shark, Heron is adamant that Australia should end its protection of the great white and start culling.

"They're top of the food chain and nothing affects it," Heron told reporters after his attack.

"It's time they started controlling the numbers. Controlled culling -- they kill our national emblem, the kangaroo, they kill elephants in Africa," he said.

"The numbers have gone up and there's too many of them," he said, adding that sharks were swimming closer to shore threatening children swimming off beaches.

But the parents of Stehbens, who fought in vain to free his leg from the shark's jaws after being attacked while diving for cuttlefish, reject calls to kill the shark.

"He was a marine biologist, he wouldn't want anything killed," said his father, David Stehbens. "Jarrod was doing exactly what he wanted to do. He loved the sea..."

Australia has a global reputation for sharks, with its cold southern waters the ideal breeding ground for great white pointers. But the chances of an attack are slim, in fact, swimmers are more likely to drown than be bitten by a shark.

By September 2005, there had been 652 shark attacks, 191 of them fatal, in Australian waters in the past 200 years, according to the Australian Shark Attack File at Sydney's Taronga Zoo.
In the past 50 years, 60 people have died after being attacked by a shark, 1.2 fatal attacks a year. This compares with two to three deaths each year from bee stings and hundreds of drownings by beach swimmers and fishermen.

TOO BONY

"Shark attacks are very prominent in the media when they occur, but they are rare events," said Barry Bruce, a government marine scientist who has studied great whites since 1987.

Great whites are "hot-spot hunters," which target oceanic biological activity, like big schools of fish, seal colonies and dead whales. The sharks do not intentionally hunt humans.

"We are not seeing a trend of increasing shark attacks against a trend of increasing population," said John West, who runs The Australian Shark Attack File.

The odds of a shark attack are 15-20 million to one, he said.

"Unfortunately, they test to see if you are edible, but they can only use their teeth or nose and in doing so they do a lot of damage to soft, squishy humans," said West.

Humans are not sharks' ideal prey because we are bony and have less flesh than seals or dolphins but unfortunately one exploratory bite by a great white, which has poor eyesight, is enough to kill most humans.

According to reports of attacks, very few great whites return for another bite.

Australia regards the great white as an endangered species and has protected it for the past 10 years. Great whites are also protected by South Africa, Namibia, the Maldives and by the U.S. states of Florida and California.

Scientists say there is no evidence that shark numbers have risen dramatically as a result of protection, as counting is impossible, and sharks have slow reproductive cycles.

Female great whites do not start reproducing until they grow to about five meters (16 feet), which takes about 15 to 20 years, and then only produce five to 10 pups every three years.

"Their reproductive potential is quite low and because of that the time it takes to increase their numbers significantly is a long time, likely to be much more than 10 years," said Bruce.

Scientists say culling would have little impact on attacks and would unbalance the food chain by removing an apex predator.

Those calling for culling also claim that shark tourism and tuna farming has attracted sharks closer to shore and swimmers.

Again, scientists discount such an argument, saying shark tourism occurs well offshore. It involves operators dumping bloody berley or fish bait into the ocean to attract sharks and then lower tourists in cages into the water.

And there are also only a handful of operators in the ocean off the state of South Australia.
"Sometimes they put berley in water and find nothing because sharks are traveling in and out of these areas," Bruce said.

Scientists say that tuna farms, which are found only off southern Australia, are not a big attraction for sharks. The fish are in big enclosures and, unlike seals or swimmers, do not offer sharks an opportunistic feed.

HUNTING HIGHWAY

Culling sharks would be very difficult and costly, scientists say, particularly as great whites travel thousands of kilometers (miles) each year along "hunting highways."

Great whites patrol an area that extends from Australia's cold southern waters to its tropical northern waters on both its east and west coasts. Usually they move north during autumn and winter and south in spring and summer.

Sharks tagged by the Australian government's Commonwealth Scientific and Industrial Research Organization (CSIRO) have been recaptured up to 1,400 km (870 miles) from the point of tagging.
Scientists say that 24 to 48 hours after an attack the chances are a great white would be hundreds of kilometers away.

Sharks also have erratic movement patterns, with electronic transmitters showing some swimming near the seabed and close to shore by day and near the surface and offshore at night.

Scientists believe that, if there is any increasing risk of shark attack in Australia, it will be caused by people, not sharks, as more leisure time means more people are entering the ocean.

"The more people in the water, and the more diverse their activities, the more chances somebody will be in the path of a hunting shark," said Bruce.