The blue swimmer is not a big bodied crab, the largest recorded blue swimmer caught to date weighed in at just over a kilo. The mangrove crab however is harder to find in southern NSW, Victoria and around the South Australian coastline. This crab, which thrives in the northern half of Australia, can grow to over five kilos. The muddy has a pair of very powerful claws which, with careless handling, can crush a finger to pulp in seconds. As a defence mechanism, the mud crab can throw one or both claws and, while the attacker concentrates on the thrown claw, the mud crab makes a quick exit to safety.
New claws take only a few seasons to form again into menacing, formidable weapons.
Crab Traps Mud crabs are caught in a variety of traps, but the main method of capture for the muddy is a strong metal envelope type trap that the crab can't destroy. The crab enters the funnel of the trap in search of the bait, gets trapped, disorientated and eventually gives up. The trap has a hinged lid giving access to fix the bait and to enable easy crab removal. A dilly net consisting of an open type net with bait inside is another proven method in catching muddies. The dilly is immersed near mangroves at the slack of the tide.