Blood on the water and teen is one lucky girl

Hannah Mighall, 13, was in a stable condition in Royal Hobart Hospital after surgery on a deep bite that ran the length of her lower right leg.

"She's going to have a good scar and a great story, but that's all," said Syb Mundy, the cousin who helped her fend off a four to five-metre great white shark on Sunday.

Bull sharks, rated by CSIRO experts as more dangerous than great whites despite their smaller size, were blamed for two other attacks within 24 hours.

Surfer Jonathon Beard, 31, was seized by the leg near Tweed Heads, NSW, on Sunday and a 24-year-old man snorkelling at Lake Illawarra yesterday had to punch himself free of a shark.

Steven Foggarty, 24, said he fought off what he thought was a bull shark that latched onto his right leg at the mouth of Lake Illawarra, south of Wollongong. on NSW's south coast. He suffered more than 50 puncture wounds to his calf, plus cuts to his fist.

"I just saw the blood all over both feet and had a quick look to make sure both legs were there and they were there," Mr Foggarty told Network Ten.

He said he punched the shark, trying to make it let him go. "I just turned and started swinging. I tried my best ... I think I got one on him."

Mr Beard suffered a massive bite to a thigh when attacked while surfing at Fingal Beach near Tweed Heads, but made it to shore with the help of friends.

In yesterday's Tasmanian attack, Mr Mundy, 33, watched horrified as Hannah disappeared when the great white dragged her, and then her surfboard, underwater at Bailey's Rocks, a remote surf spot on Tasmania's north-east coast. "She came up and was flapping and screaming, 'Get it off me, get it off me'," he said.

He paddled his board over to her and tried to to push the shark away, but she went down a third time when the shark bit the board and dragged her under.

Mr Mundy said Hannah then swam to him and climbed onto his back as he paddled for shore, with the shark circling. As it rose towards them, they turned to face it, then made for shore again. "Then a wave came along and I said: 'No matter how weak you are, try to hang on. This wave is going to save our lives'."

He said the shark appeared in the wave to their left, but they were able to reach shore where bystanders helped them.

Mr Mundy said the pluck of his young cousin made him proud. "She gave me the strength to stay there with her in the water when I saw the way she was fighting it off."

Queensland shark exhibitor Vic Hislop said more shark attacks were likely because of declining fish stocks. He said now chasing "gentler" prey such as dugong, turtles and dolphins.

"That's what's in their stomach now every day," Mr Hislop said. "As the turtles disappear, which is inevitable, and the dugong herds disappear, humans are next in line on the food chain."

Mr Hislop said humans were tasty to sharks but managed to escape because they're smarter than most prey. "Don't ever believe this rubbish about 'they take a bite, they don't like humans'," he said. "They take a bite and wait for their victim to bleed to death to finish them off. And that's why we escape."

The great white is listed as vulnerable, under pressure from fishing. CSIRO marine biologist John Stevens said it was likely to be some time before its numbers would increase generally. -- With THE EXAMINER, AAP