Bondy, while the sort of equipment you are talking about is used extensively in the commercial sector for fish traps etc. it is not legal for recreational crabbing in Queensland
When not attached to a fixed object (for example tied to a tree above the high water mark), all crab apparatus must have a light coloured surface float attached. The float must not be less than 15 cm in any dimension and must be marked clearly with the owner's name.
When tied to a fixed object, a tag must also be attached to part of the rope that is above the high water mark. The tag must be marked clearly with the owner's name.