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SYDNEY - Humans have always been tasty morsels for big sharks and will head the menu if fishing in Australian waters is not brought under control, shark expert Vic Hislop has warned.
Mr Hislop, who has hunted sharks for decades, says most beliefs about shark attacks on humans are wrong.
Separate shark attacks on Sunday left a male surfer at Tweed Heads, in far north NSW, and a teenage girl in Tasmania with gaping leg wounds.
In the first attack, by a suspected bull shark, the surfer escaped with a 40cm tear to his thigh.
Hours later, a five metre great white shark latched on to the leg of 13-year-old Hannah Mighall at Binalong Bay, near St Helens, in Tasmania's north-east.
Her older cousin fought off the "monster" and then the pair rode a wave into shore with the shark close behind.
Mr Hislop said 200 years of over-fishing Australian waters had turned the attention of big sharks to "gentler" prey such as dugong, turtles and dolphins.
"That's what's in their stomach now every day," he told Macquarie Radio on Monday.
"As the turtles disappear, which is inevitable, and the dugong herds disappear, humans are next in line on the food chain.
"It will definitely get worse."
Mr Hislop said humans are tasty to sharks but manage to escape because they're smarter.
"Don't ever believe this rubbish about 'they take a bite, they don't like humans'," he said.
"That is just so wrong. They take a bite and wait for their victim to bleed to death to finish them off. And that's why we escape."
Marine animals bitten by sharks panicked, swam around and bled to death before the shark moved in again to devour them, he said.
But human defence mechanisms would eventually fail against the shark.
"The big sharks only lose a few people then they get good at it," Mr Hislop said.
Hitting a shark on the nose or trying to poke one in the eye to fight off an attack was not effective and did not cause a shark to release a victim, he said.
"You can get 10 of the biggest men in Australia with sledgehammers and you will not hurt them. You won't even faze them," Mr Hislop said.
Commercial fishing levels and the protection of great white sharks would result in more attacks on humans, he said.
"Common sense tells you that you cannot keep fishing out the oceans and protect the end of the food chain. You're heading for disaster."
- AAP
