Australian Seal
Australian Seals aren't actually seals at all, they're sealions. The naming guy got it wrong as he does so often underwater.
However, sealions isn't a great name either. The fact is they would be better off being called seadogs. They act like dogs, bark underwater like dogs, they even give births to pups. When you see their faces underwater it is spooky how much they look like dogs. They are yet another contender for a name change.
There are usually a few resident seals in Sydney - especially in Pittwater.