THE great white, witdoodshaai, squalo bianco, grand requin blanc, menschenhai, the man-eater and even the white death.
Nanjing Night Net

A CSIRO shot of a great white off Port Stephens.

Humans know many names for Carcharodon carcharias but much about the world’s largest predatory fish remains a mystery.

Great whites are the apex oceanic predator and are found throughout Australian waters, from the bight to the Torres Strait.

They use the continental shelves like highways and some can travel thousands of kilometres in a few months.

But no human has ever seen a great white mate or give birth. There are just a handful of nurseries along the coast where juveniles congregate before they’re big enough for the open ocean.

One is off Stockton beach and large numbers of young great whites regularly swim within the surf line, beneath unsuspecting bathers.

But great white attacks are extremely rare given the number of people entering the water each year.

In Australia, there have been nine fatal attacks blamed on great whites since 2002 but Griffith University’s Dr Jonathan Werry believes we don’t have much to worry about.

There are many theories about why they attack humans – we look like seals when wearing wetsuits, or maybe sharks associate us with food because of excessive chumming by shark cage diving operators and fishing fleets – but none are proven.

Dr Werry saw a pattern emerging from the incidents (he doesn’t call them attacks). He said most occurred in areas far away from known great white nurseries and feeding grounds.

‘‘The sharks involved are just passing through the area,’’ he said. ‘‘They’re not locals, so to speak.

‘‘Sharks are not crocodiles. Humans are prey for crocodiles every time.

‘‘But great whites may be different to other sharks. We need to do more research on them to find out.’’

However, Dr Werry said it was extremely important to preserve great whites, not just because removing them would upset the ecosystem’s food chain.

He said great whites’ vertebrae, skin and tissue held a record of the environment, like tree rings or ice cores.

Great whites can live for up to 70 years and act like oceanic encyclopedias, storing decades of information about pollution levels and fish stocks.

Dr Werry said a four-metre male white was recently found dead with its huge head stuck in an underwater cave off Sydney Harbour. When researchers ran tests on its body, they found it had been poisoned by a build-up of toxins.

‘‘There were moderate amounts of these toxins in the harbour but the animal died because of years of exposure, causing an overload in its system,’’ he said. ‘‘If that sort of thing is happening at the top of the food chain, it must be occurring lower down.’’

Dr Werry believed that if we could learn more about great whites, we could protect them, humans and the oceans. AAP

■ Don’t panic – panicking will cause you to lose concentration

■ Don’t poke or punch – punching a shark will only anger it, and trying to poke its eyes on the side of its head will only put another limb within bite range

■ Hug – if the shark bites your arm, try to hug it or move your arm with its head as it thrashes from side to side

■ Wait – the shark will eventually need to take another bite; wait until it lets go and then pull your limb away

■ Curl – into a ball; if the shark comes back, it will have less to bite onto if your arms and legs are tucked in

■ Douse and wrap – slather your wound in disinfectant and wrap it in cling film; this will apply pressure and hold your limb together better than a soggy bandage