Correct identification is vital as the brown and green mud crab have different size limits.
Mud crabs are found in WA's north-west from Shark Bay to the Northern Territory border. If a mud crab is smaller than 150 mm wide (green) or 120 mm wide (brown) you must release it immediately.
But how do you tell if you’ve caught a green or a brown?
Although similar in appearance, there are key differences. The green has more than one large sharp spine on its elbow and big, distinct spines on its claw. The brown has one small blunt spine or no spines on its elbow and its claw spines are small or just bumps.
Measure each crab across the widest part of the shell, from tip to tip of the spikes, using a gauge from a tackle store.
Any mud crab carrying eggs must also be released immediately.
For more information see the recreational fishing rules.
You can also download our 
Recreational fishing guide and Recreational fishing identification guide or pick up a copy of both guides from our offices and participating information outlets.