Indo-pacific swamp crab total production thousand tonnes 1950-2022

''Scylla serrata'' (often called mud crab or mangrove crab, although both terms are highly ambiguous, and black crab) is an ecologically important

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

crab Crabs are decapod crustaceans of the infraorder Brachyura (meaning "short tailed" in Greek language, Greek), which typically have a very short projecting tail-like abdomen#Arthropoda, abdomen, usually hidden entirely under the Thorax (arthropo ...

found in the

estuaries An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environm ...

and

mangrove A mangrove is a shrub or tree that grows mainly in coastal saline water, saline or brackish water. Mangroves grow in an equatorial climate, typically along coastlines and tidal rivers. They have particular adaptations to take in extra oxygen a ...

s of Africa, Australia, and Asia. In their most common forms, their shell colours vary from a deep, mottled green to very dark brown.

Distribution

The natural

range Range may refer to: Geography * Range (geographic), a chain of hills or mountains; a somewhat linear, complex mountainous or hilly area (cordillera, sierra) ** Mountain range, a group of mountains bordered by lowlands * Range, a term used to i ...

of ''S. serrata'' is in the

Indo-Pacific The Indo-Pacific is a vast biogeographic region of Earth. In a narrow sense, sometimes known as the Indo-West Pacific or Indo-Pacific Asia, it comprises the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the ...

. It is found from South Africa, around the coast of the Indian Ocean, where it is especially abundant in

Sri Lanka Sri Lanka, officially the Democratic Socialist Republic of Sri Lanka, also known historically as Ceylon, is an island country in South Asia. It lies in the Indian Ocean, southwest of the Bay of Bengal, separated from the Indian subcontinent, ...

, to the Southeast Asian Archipelago, as well as from southern Japan to south-eastern Australia, northern New Zealand, and as far east as Fiji and Samoa. The species has also been introduced to Hawaii and

Florida Florida ( ; ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders the Gulf of Mexico to the west, Alabama to the northwest, Georgia (U.S. state), Georgia to the north, the Atlantic ...

. In

Hawaii Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only sta ...

, mud crabs are colloquially known as Samoan crabs, as they were originally imported from American Samoa. As these crabs are known for their robust size and dense meat content, they have been greatly sought after over the years. As a result of overcrabbing, local government efforts have restricted harvesting of crabs smaller than 6 inches (width across back) and to harvest females of any size is illegal.

Ecology

A study on tidal flats in Deception Bay in Queensland found juvenile crabs ( carapace width) were resident in the

zone, remaining there during low tide, while subadults () migrated into the

intertidal zone The intertidal zone or foreshore is the area above water level at low tide and underwater at high tide; in other words, it is the part of the littoral zone within the tidal range. This area can include several types of habitats with various ...

to feed at high tide and retreated to subtidal waters at low tide. Adults ( and larger) were caught mainly below the low-tide mark, with small numbers captured in the intertidal zone at high tide. These crabs are highly cannibalistic in nature; when crabs undergo molting, other hard-shelled ones sometimes attack the molting crabs and devour them. The females can give birth to a million offspring, which can grow up to in size and have a shell width up to wide.

References

External links

Australia: Queensland government page on mangrove crab aquacultureCycle of the mud crabLife Cycle of the Mud Crab – Fishnote No.11 March 2007, Northern Territory
{{Authority control Portunoidea Crabs of the Indian Ocean Crabs of the Pacific Ocean Edible crustaceans Commercial crustaceans Crustaceans described in 1775 Taxa named by Peter Forsskål Australian cuisine