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Biological Information on Mud Crabs 

Mud Crabs are dark brown to green coloured crabs that live in muddy sheltered habitats which belong to the portunidae family of crabs. Characteristically they have a broad smooth shell called a carapace, six walking legs, two chelipeds (claws) and two flattened legs for swimming 

where are they found?

Mud Crabs are selective to coastal areas/habitats that contain mangroves. They prefer muddy sheltered environments in estuaries where they are able to dig out holes with their sharp claws and burrow inside—it acts as a home and a protects them from predators.  Mud Crabs can also be found all the way out in seagrass areas but in close proximity to mangroves. 

what do they feed on?

They feed on Immobile or slow-moving animals such as bivalve shells, marine worms, molluscs and even on small crabs . They also eat plant material.  Mud crabs come out from their burrows at night to forage for food. 

lifecycle of a mud crab

Mud Crabs Mate in their natural habitat in mangrove forest. Berried (carrying eggs) females migrate offshore, as far as 50km, to spawn (release eggs) in the ocean, then swim back to their habitat. The larvae travels with tides and currents back into Intertidal shores as they develop and settle in their natural habitat as young crabs, until they mature. 

species profile and identification

Four main species found in Papua New Guinea:

Mud Crab
Scylla serrata

Orange Mud Crab
Scylla Olivacea

Green Mud Crab
Scylla Paramamosain

Purple Mud Crab
Scylla Tranquabarius

identifying mud crab

you can identify if a Mud Crab is male of female by looking at the abdominal area: 




In order for the life cycle of mud crabs to occur, it is important to protect habitats that are part of this life cycle process. 

Habitats include: 

1. Mangrove forests 

2. Seagrass areas (inter-tidal zone) 

3. Coral reefs 


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