Basically if you thrash about for many Shark species, it excites them a tad, some more than others.
The Tiger Shark prefers a prey that doesn't move as much - being a scavenger, it prefers something 'dead' looking.
Most Sharks hone in on the smell of urine/wee wee in the water as a person can thus actually smell like an animal.
This was the case for one South African Surfer who survived x3 Great White Attacks (once with two at the same time!

) - the reason why they always chose him amongst the others is because he Wee-Wee a lot in the water.
Being fully clothed (ie: shoes, socks, long pants) does help to nullify the smell of skin a lot.
Sharks are colour-blind, they only see things in contrast of bright & dark.
Most GWShark attacks in WA have been via Scuba Divers 'spearfishing', which is legal in WA. The dead fish attracting the Sharks. On one occasion, such Scuba Spearo's returned to the same spot the following year after they lost a mate to a GWShark and were (obviously

) attacked again.
Certain Beaches are known 'hot spots' for Shark activity, with Sharks hanging off the 'Points' for some 'oxygenation' - but many 'Surfers' flaunt the 'bravado' of surfing such places and basically just 'ask for it', although they insist the Sharks should be culled away.
Education is the main advantage, especially getting to know the area you are about to swim/dive in.
The lady at Tathra may have been better off not to become isolated, let alone swimming at the Dawn/Dusk periods.
The Navy Diver who got attacked in Sydney Harbour: the place was known by locals as a feeding spot for Bulls at Dusk.
Lady in QLD who got taken by Bullsharks, wadding in knee-deep water with her dog in an 'estuary' entrance which are common 'hotspots' for shark activity especially when the tide is going out.
Me? Well when snorkling off Port Lincoln at 5 metres deep, I suddenly found myself with a Kingfish and his 3 wives hugging me closely I could touch them. Then I remembered being in Gordons Bay (Scuba) in Sydney when surrounded by a Baitball of fish (sounded like a chandelier moving about) for 'protection' from the attacking KingFish.
So I decided to move closer to shore - just in case.
WA & SthAust Great Whites are a different breed of Shark to those of the Tasman Sea, although they both mix around Tasmania, they never interbreed. I consider the Tasman Sea Great Whites a bit more 'placid' ...maybe because there are more ORCA to keep them 'humble'.

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