In reality it isn't really a problem.
You just have to use common sense.
Snakes are everywhere but hardly anyone ever sees one, they avoid humans.
When swimming you have to accept there are sharks in the water but it is very rare that anyone gets attacked, when they do it is mostly in colder waters
Up north crocodiles are a real threat so if the sign says stay out of the water then ......................
I currently live just south of Brisbane and there are lots of canals and lakes built by developers, you can't swim in them because they are full of bullsharks.
Bullsharks are the most dangerous and live in both salt and fresh water
This is in a lake about 3kms from me.
Our holiday house is 3 hours north of Brisbane and only occasionally after extreme weather do you get jellyfish and a rare crocodile there.