"Generally, crabs that are low on meat have recently moulted their shell and have not had a chance to fill their body cavity with flesh," Mr McDonald said.
"Recently moulted crabs will often contain mostly liquid or a jelly mass with little edible flesh.
"Whether you're an avid crabber, or you buy them at the local market, you can ensure every crab you catch or buy is full by following a few simple tips.
"Firstly, take a look at the shell condition. A crab that has recently moulted will have a very clean, shiny and intact shell. Sometimes the shell will appear translucent.
"Full mud crabs often have algae or barnacles on the shell. Their shells are also likely to exhibit some general signs of wear and tear, such as worn inner 'teeth' on the claws.
"You should also look for the darker coloured maltese cross on the underside of the crab."
Mr McDonald said there were also areas on the crab shell that could be pressed in order to get an indication of fullness.
"You can apply pressure with your thumb and finger either side of the carapace or by turning the crab over and pressing firmly on the abdomen plates adjacent to the third leg. If the shell flexes at all, the crab is not full.
"For crabs where the shell appears new, be careful not to press too hard as your thumbs will penetrate the shell.
"Crabbers should ensure the crab is firmly tied or restrained before attempting to test the shell."
Mr McDonald urged crabbers to return empty mud crabs to the water as soon as possible.
"Mud crabs grow very rapidly after moulting their shells," he said.
"When empty mud crabs are returned to the water they become full of meat and are a better quality catch within a few weeks.
"Returning empty mud crabs to the water is important for the sustainability of the fishery."
March 2015
