4. Bull shark

A bull shark.

IMAGE: CORBIS IMAGES

Found worldwide in coastal waters, you're most likely to come across the bull shark in estuaries, harbours and rivers.

It's a very good scavenger, as well as a predator, Robinson said, so you certainly don't want to be swimming near any dead whale carcasses. It's probably responsible for most of the dogs that go missing from the water, he added.

Danger rating: 8/10

Scientific name: Carcharhinus leucas

How to know if it's got you: Oh, you'll know.