Scylla serrata
Encyclopedia
Scylla serrata is an economically important crab species
found in the estuaries
and mangrove
s of Africa
, Australia
and Asia
. In their most common form, the shell colour varies from a deep, mottled green to very dark brown. Generally cooked with their shells on, when they moult
their shells, they can be served as a seafood delicacy, one of many types of soft shell crab
. Some consider them to be among the tastiest of crab species and they have a huge demand in South Asia
n countries where they are often bought alive in the markets. In the northern states of Australia
and especially Queensland
, mud crabs are relatively common and generally prized above other seafood within the general public.
These crabs are highly cannibalistic in nature and when another crab undergoes moulting the hard shelled ones attack the moulting crabs and devour them. The females can give birth to 1 million offspring which can grow up to 3.5 kilograms (7.7 lb) in size and have a shell width of up to 24 centimetres (9.4 in) wide.
Mud crab can be killed by placing them in a freezer for up to two hours.
(particularly NH3) (twice that of the similar sized Portunus pelagicus
), which is beneficial because ammonia-N is often the most limiting factor on closed aquaculture systems. Their high ammonia-N tolerance may be attributed to various unique physiological responses which may have arisen due to their habitat preferences. However their aquaculture has been limited due to the often low and unpredictable larvae survival. This may be due to inadequate nutrition, disease, "moult death syndrome" (due to their highly cannibalistic behaviour during the megalopa stage), inadequate protocols (e.g. sub-optimal environmental conditions) or a combination of all.
S. serrata can be kept easily in home aquaria when smaller, but will outgrow small setups. They are very active and will eat almost any conventional sinking pellets; they also appreciate some small fish pieces and vegetable matter. They are tolerant of most water conditions and are generally a very hardy and entertaining species.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
found in the estuaries
Estuary
An estuary is a partly enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea....
and mangrove
Mangrove
Mangroves are various kinds of trees up to medium height and shrubs that grow in saline coastal sediment habitats in the tropics and subtropics – mainly between latitudes N and S...
s of Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
, Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
and Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
. In their most common form, the shell colour varies from a deep, mottled green to very dark brown. Generally cooked with their shells on, when they moult
Ecdysis
Ecdysis is the moulting of the cuticula in many invertebrates. This process of moulting is the defining feature of the clade Ecdysozoa, comprising the arthropods, nematodes, velvet worms, horsehair worms, rotifers, tardigrades and Cephalorhyncha...
their shells, they can be served as a seafood delicacy, one of many types of soft shell crab
Soft shell crab
Soft-shell crab is a culinary term for crabs which have recently molted their old exoskeleton and are still soft.In the United States, the main species is the "blue crab", Callinectes sapidus, which appears in markets from April to September...
. Some consider them to be among the tastiest of crab species and they have a huge demand in South Asia
South Asia
South Asia, also known as Southern Asia, is the southern region of the Asian continent, which comprises the sub-Himalayan countries and, for some authorities , also includes the adjoining countries to the west and the east...
n countries where they are often bought alive in the markets. In the northern states of Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
and especially Queensland
Queensland
Queensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
, mud crabs are relatively common and generally prized above other seafood within the general public.
These crabs are highly cannibalistic in nature and when another crab undergoes moulting the hard shelled ones attack the moulting crabs and devour them. The females can give birth to 1 million offspring which can grow up to 3.5 kilograms (7.7 lb) in size and have a shell width of up to 24 centimetres (9.4 in) wide.
Mud crab can be killed by placing them in a freezer for up to two hours.
Aquaculture
There has been a huge interest in the aquaculture of this species due to their high demand/price, high flesh content and rapid growth rates in captivity. In addition they have a high tolerance to both nitrate and ammoniaAmmonia
Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...
(particularly NH3) (twice that of the similar sized Portunus pelagicus
Portunus pelagicus
Portunus pelagicus, also known as the flower crab, blue crab, blue swimmer crab, blue manna crab or sand crab, is a large crab found in the intertidal estuaries of the Indian and Pacific Oceans and the Middle-Eastern coast of the Mediterranean Sea. The name "flower crab" is used in east Asian...
), which is beneficial because ammonia-N is often the most limiting factor on closed aquaculture systems. Their high ammonia-N tolerance may be attributed to various unique physiological responses which may have arisen due to their habitat preferences. However their aquaculture has been limited due to the often low and unpredictable larvae survival. This may be due to inadequate nutrition, disease, "moult death syndrome" (due to their highly cannibalistic behaviour during the megalopa stage), inadequate protocols (e.g. sub-optimal environmental conditions) or a combination of all.
S. serrata can be kept easily in home aquaria when smaller, but will outgrow small setups. They are very active and will eat almost any conventional sinking pellets; they also appreciate some small fish pieces and vegetable matter. They are tolerant of most water conditions and are generally a very hardy and entertaining species.