Mud Crab

 

Characteristics

The mud crab is between 10cm to 13cm in size as a full-grown adult. Juveniles are usually between 2cm to 10cm in size. Males are smaller than females. They can be distinguished by their shell colours - brown and green. They have big nippers as hands.

 

Behaviour

• Foraging: Mud crabs emerge at night to forage for food; they eat almost anything. However, they mainly eat slow-moving or stationary bottom-dwelling animals such as molluscs, smaller crabs and worms. They also eat plant material.

• Reproduction: Mating – In the warmer months, mature females release a ‘pheromone’ (chemical attractant) into the water to attract males. Once paired the male climbs on top of the female, clasps her with his hind legs, picks her up and carries her around for up to four days.

• Offensive/Defensive: Crabs fight for food and shelter, they use the nippers to attack and defend in these situations.

• Migratory: Females when pregnant with eggs move to calmer waters and when born eggs flow back up rivers in the current.

 

Diet

The mud crab is a consumer and preys on dead organisms, molluscs, smaller crabs, plant material and worms. This makes it an omnivore. They also compete with small fish and other crabs for food.

 

Predators

The mud crabs predators are fish, crocodiles, birds, sharks, turtles and rays.

 

Distribution and Abundance

They inhabit tropical and subtropical coastal or salt waters of south Asia and north east to north west Australia. They inhabit tropical and warm temperate waters from Exmouth Gulf in Western Australia to the Bega River in New South Wales. Mud crabs are found in most coastal rivers and creeks but are not found towards Alice Springs and Tennant Creek.

 

The abundance of mud crabs worldwide has increased over the years due to word of mouth; it is said the Mud Crab is a good tasting crab. Fishing size limits have been made as well, which has added to the increase in numbers.

 

Habitat

The Mud Crab inhabits sheltered waters such as estuaries and mangrove areas.

 

Management

It is not a protected species but it is regulated. Management for Mud Crab includes legal sizing limits (14cm females and 13cm males) and amounts of Mud Crabs available to take on a boat at a time (up to 10).  In Queensland, female mud crabs are protected and you need a permit to keep one.