Since commercial fishing ceased in Lake Mac the sightings of sharks has really increased, water temp is right and there's now plenty of food for them to eat.
You'd be quite surprised if you actually knew many sharks are in the lake, I for one will not swim in the lake. I've seen plenty of hammerheads around Pulbah Island and bull sharks up to 2.5m in the southern end of lake, even up Dora Creek.
A few years ago I caught a bull shark there, approx 1.8m in length. Living so close to there I am always fishing there.