THE great white circles and gives chase when bloody bait is thrown in the water and dragged back across the top of a submerged cage full of startled tourists.
Matt Waller, a charter operator off the South Australian coast, calls it the "Jaws experience".
"It's an adrenaline rush," he tells the Herald. "They are trying to give people a good scare."
For thrill seekers, a shark cage adventure ticks all the boxes. Get up close and personal with an apex predator in its own habitat, safe behind iron bars.
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Surfers and divers lack such protection when they enter the water, and some worry the lucrative tours are changing shark behaviour.
"You can't go to Yellowstone Park and bait up a bear," says abalone diver Jonas Woolford. "Yet that's effectively what is happening here with great whites."
Woolford echoes growing public concern that the popular tourist craze could be teaching sharks to associate boats, cages and humans with food.
Last month a great white ripped off a surfer's leg 20km from where the shark boats operate. The victim, 26-year-old Chris Blowes, remains critically ill in hospital.
"You train animals using food and you're always told not to feed wild animals," adds Woolford. "I don't understand why the approach to sharks should be any different."
Tourists are lowered into waters off the Neptune Islands, a 2-hour boat trip from the town of Port Lincoln on the tip of the Eyre Peninsula.
It's the only spot in Australia where shark cage vessels are licensed to operate. Similar experiences are available in South Africa and, closer to home, off Stewart Island.
A 2011 report by Australia's national science agency, the CSIRO, discovered that tagged sharks stayed longer in the Neptune zone, and came closer to the boats.
The authors recommended a reduction in berleying, where blood and bait are spread in the water.
Calypso Star Charters is one of two licensed operators using this method to lure sharks. The third company, Waller's Adventure Bay Charters, prefers "acoustic attraction".
They have been credited with drawing 15,000 tourists to Port Lincoln each year, many of whom pay up to A$500 ($530) to go "face to face" with fearsome 5m predators.
Calypso general manager Andrew Wright harbours bigger ambitions. He said Sydney, the Great Barrier Reef and Uluru topped Australia's visitor attractions. "We're sort of moving to get cage diving on that list of things to do," he said.
The limitations of the current set-up were highlighted in spectacular fashion in February.
Tourists aboard Waller's charter boat filmed a pod of killer whales attacking and killing a great white. The sharks then abandoned the cage diving area for almost three months.
To "drought proof" their industry, the three cage operators have asked the state government for permission to take tourists to alternative sites off the Peninsula - provoking a backlash from divers, surfers and other water users.
While the operators insist they do not want changes that will be detrimental to other water users, they point to the lack of scientific evidence linking shark cage tourism to an increased risk to human safety.
Waller used to attract sharks with blood and bait, but turned to acoustic technology following an industry dispute. "We used to get sharks biting cages," he says.
"To me it was exciting and fun. But when I started doing it this other way my level of respect for the great white shark changed considerably.
"If a shark is chasing after bait and at the last minute closes its eyes or rolls them back in its head, as they're prone to do to protect themselves, and slams head first into a cage, that isn't good for the sharks."
Waller says it's unfair to accuse his industry of "habitualising" behaviour. Industries such as commercial fishing and aquafarming, he says, also attract sharks.
"The really tough thing about our industry is it's actually quite emotional," he says. "Shark attacks hit a raw nerve. It's a very primeval fear.
"At the moment what you've got is mostly speculation filling that void, and that's dangerous."
Woolford, president of the South Australian Abalone Industry Association, hopes shark cage tourism will continue but without blood and bait.
"Australia has a beach culture, particularly down here on the peninsula," he says. "Hundreds of businesses rely on people being in or around the water, but if people become scared to go near the water the consequences will be huge. That has to outweigh the benefits cage tourism has for a few businesses."
Rising shark "interactions" have altered Woolford's own behaviour.
"I no longer surf at dawn and dusk like I used to, and I won't sit out on the water for long periods."