some species of sharks are protected (as most of you probly know), but bronze whalers are aggressive, and so are bull sharks. not nice to tangle with so I'm told.
It's unusual to find two different species attacking someone, or anything really. Bronze whalers are a fair bit smaller that Whites, so it'd be interesting (but morbid) to see if they can work out which shark began the attack.
tips for surfers/boarders/goatboaters- if there are a lot of birds diving into the water, focusing on a particular area there is an increased likely hood of sharks. birds congrgate where the fish are, and so do sharks. don't go into the water if the birds are diving close to the beach. if you get between a school of fish and a shark you are food. badness.
for people who go to stockton beach (yay Newie!!) there are Bull sharks there all the time, generally off the beach a fair bit, they stay near the mouth of the harbour, but when the pelicans come close to the beach to feed stay away. well away.