Just curious. You know there is a lot of warm ocean to swim in around Australia. Sounds fun to me.
http://www.travel-images.com/tasmania3.html
It's kinda quaint - turn your clock back at least 50 years.
As my Australian friends told me:
"Everything in Australia bites - and it's poisonous."
An exageration to be sure, but actually not that far off!
As far as swimming in the ocean, witness the Blue-ringed octupus:
http://www.didyouknow.cd/animals/octopus.htm