When I was a kid I'd go down to the stream in Willeton/Riverton which is part of the storm water system.

You'd throw bricks with the 6 holes in them in the stream and wait or look for ones others had left in there.

You'd go up to the bricks and quickly flick them up onto the shore and generally you'd get what I'm pretty sure was Gilgies

Fun times =)

I've heard of Gilgies when there's water at serpentine falls but I tend not to bother them there being a more natural environment

You could try Herdsman lake although I'm unsure if there's regulations about it
When my Dad was young he'd catch them and cook them up on a tin can with water over the fire

Can I suggest no nets, these areas also have turtles and being trapped in an opera net will drown them =(