I don't specifically target bigger fish, I have speared a few small snapper (approx 1kg), but compared to further west or north, Victoria doesn't have much in the way of big fish opportunities. When I am SCUBA diving for crays, sometimes if I find one that is deep in it's cave, I will cut up an abalone and wave it near the entrance to the cave, they almost always come out, but sometimes they take a while. If you're patient, and stay VERY still, you can get them to come out and sit on your hand using this method. Difficult on snorkel though, you'd have to somehow anchor the bait to the bottom and watch it from the top, then dive when the cray comes out. It could work.
Jaz
Jaz