There have been really tight restrictions on shark fishing and by-catching in Australian waters for many years now, and current research suggests that shark numbers are higher than they've ever been in recent history.
It's actually getting to the point where I think twice about going in the water in some places.
Moreton Bay which is right on our doorstep seems to have a very high concentration of sharks IMO.
Attacks are on the rise!
Oh and btw, that looks like a dolphin to me.