Ragamuffun, unsure of the laws in Victoria, but you probably need a day-long fishing licence. There are rules against taking females in berry, so keep that in mind as i'm fairly sure the fines are pretty big.
Apparently the opera house style traps are reasonable for catching cray, and I don't know if they fall under a different licencing scheme.
Contact the Victorian fisheries dept, they will be able to help
And if you get a few, send one my way! They are gorgeous
