Portunus pelagicus | |
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Male | |
Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Class: | Malacostraca |
Order: | Decapoda |
Suborder: | Pleocyemata |
Infraorder: | Brachyura |
Family: | Portunidae |
Genus: | Portunus |
Species: | P. pelagicus |
Binomial name | |
Portunus pelagicus | |
Synonyms | |
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Portunus pelagicus, also known as the blue crab, blue swimmer crab, blue manna crab and flower crab is a species of large crab found in the Indo-Pacific, including off the coasts Indonesia, [1] Malaysia, [2] Cambodia, [3] Thailand, [4] the Philippines, [5] and Vietnam; [6] and in the intertidal estuaries around most of Australia and east to New Caledonia. [7]
The males are bright blue in color with white spots and with characteristically long chelipeds, while the females have a duller green/brown, with a more rounded carapace. The carapace can be up to 20 centimetres (7.9 in) wide.
They stay buried under sand or mud most of the time, particularly during the daytime and winter, which may explain their high tolerance to ammonium (NH4+) and ammonia (NH3). [8] They come out to feed during high tide on various organisms such as bivalves, fish and, to a lesser extent, macroalgae. They are excellent swimmers, largely due to a pair of flattened legs that resemble paddles. However, in contrast to another portunid crab ( Scylla serrata ), they cannot survive for long periods out of the water.
The species is commercially important throughout the Indo-Pacific, where they may be sold as traditional hard shells, or as "soft-shelled" crabs, which are considered a delicacy throughout Asia. The species is highly prized as a substitute for Callinectes sapidus . This species is fished heavily and almost exclusively for meat consumption in the Persian Gulf, with the females sold at higher prices than males.
These characteristics, along with their fast growth, ease of larviculture, high fecundity, and relatively high tolerance to both nitrate [10] [11] and ammonia, [8] (particularly ammoniacal nitrogen, NH3–N, which is typically more toxic than ammonium, as it can more easily diffuse across the gill membranes), makes this species ideal for aquaculture.
The species is commercially fished in Australia, and is also available to recreational fishers and is regulated by various state governments. Relevant recreational fishing regulations for Australia (as of March 2016) are tabled below.
State | Minimum carapace | Bag limit | Boat limit | Possession Limit | Notes |
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South Australia | 11 cm | 20 (Gulf St Vincent) or 40 (combined with sand crabs) | 60 (Gulf St Vincent) or 120 (combined with sand crabs) | N/A | [12] |
New South Wales | 6 cm | 10 | N/A | 20 | [13] |
Western Australia | 12.7 cm | 20 or 10 (West Coast) | 40 or 20 (West Coast) | N/A | Cockburn Sound is closed. Peel-Harvey Estuary is closed from 1 September to 31 October. [14] [15] |
Queensland | 11.5 cm | No limit | No limit | No limit | [16] |
Northern Territory | N/A | N/A | N/A | 30 | Combined total for any crab species other than mud crabs. [17] |
P. pelagicus commonly enters estuaries for food and shelter. Its life cycle is dependent on estuaries as the larvae and early juveniles use these habitats for growth and development. Prior to hatching, the female moves into shallow marine habitats, releases her eggs, and the newly-hatched zoea I larvae move into estuaries. During this time, they feed on microscopic plankton and progress from the zoea I stage to the zoea IV stage (approximately 8 days) and then to the final larval stage of megalopa (duration of 4–6 days). This larval stage is characterised by having large chelipeds used to catch prey. Once the megalopa metamorphoses to the crab stage, they continue to spend time in estuaries which provides a suitable habitat for shelter and food. However, evidence has shown that early juveniles cannot tolerate low salinities for extended periods, which is likely due to its weak hyper-osmoregulatory abilities. [18] This may explain their mass emigration from estuaries to seawater during the rainy season. Male Portunus pelagicus are believed to become more territorial in colder water. This may explain why male crabs are rarely sighted within a close proximity to each other in more temperate waters; it also may explain why their female counterparts seem more prolific in these areas.
The movement of this species of crab is the basis for the dance steps and movements of the Linambay, a variation of the Moro-moro that originates from Carcar, Cebu, in the Philippines, where the crab is called "Lambay".
Nitrate is a polyatomic ion with the chemical formula NO−
3. Salts containing this ion are called nitrates. Nitrates are common components of fertilizers and explosives. Almost all inorganic nitrates are soluble in water. An example of an insoluble nitrate is bismuth oxynitrate.
Portunus is a genus of crabs which includes several important species for fisheries, such as the blue swimming crab and the Gazami crab. Other species, such as the three-spotted crab are caught as bycatch.
Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting tail-like abdomen, usually hidden entirely under the thorax. They live in all the world's oceans, in freshwater, and on land. They are generally covered with a thick exoskeleton. They generally have five pairs of legs, and they have pincer claws on the ends of the frontmost pair. They first appeared during the Jurassic period, around 200 million years ago.
Callinectes sapidus, the blue crab, Atlantic blue crab, or, regionally, the Maryland blue crab, is a species of crab native to the waters of the western Atlantic Ocean and the Gulf of Mexico, and introduced internationally.
Portunus trituberculatus, also known as the gazami crab, Asian blue crab or horse crab, is the most widely fished species of crab in the world. It is found off the coasts of East Asia and is closely related to Portunus armatus.
The Peel-Harvey Estuarine System is a natural estuarine system that lies roughly parallel to the coast of Western Australia and south of the town of Mandurah.
Ovalipes catharus, commonly known as the paddle crab, swimming crab, or Māori: pāpaka, is a species of crab in the family Ovalipidae. They are found in shallow, sandy-bottomed waters around the coasts of New Zealand, the Chatham Islands, and uncommonly in southern Australia. They are opportunistic and versatile feeders active mostly at night, preying predominantly on molluscs and crustaceans. They are also highly prone to cannibalism both as part of their regular diet and as part of their mating behaviour. Their paddle-shaped rear legs and streamlined carapace allow them to swim rapidly to capture prey and to burrow in the sand in order to escape predation. Their mating season is in winter; the male carries the female until she moults, after which the two mate and the female moves into deeper waters to disperse her larvae.
Notomithrax ursus, known as the hairy seaweed crab, is a spider crab of the family Majidae.
The King George whiting, also known as the spotted whiting or spotted sillago, is a coastal marine fish of the smelt-whitings family Sillaginidae. The King George whiting is endemic to Australia, inhabiting the south coast of the country from Jurien Bay, Western Australia to Botany Bay, New South Wales in the east. The King George whiting is the only member of the genus Sillaginodes and the largest member of the smelt-whiting family Sillaginidae, growing to a length of 80 cm and 4.8 kg in weight. The species is readily distinguishable from other Australian whitings by its unique pattern of spots, as well as its highly elongate shape. King George whiting are often found in bays and protected waterways over sand and seagrass beds, also venturing out onto deep continental shelf reefs during adulthood. The species is a benthic carnivore, consuming a variety of crustaceans, polychaete worms, molluscs and fish. The King George whiting forms the basis of one of southern Australia's most important commercial fisheries, reportedly worth over five million Australian dollars per year. The species is also heavily targeted by recreational anglers, who value the whiting for its sporting and eating qualities.
The sand whiting, also known as the summer whiting, yellowfin whiting or blue-nose whiting, is a common species of coastal marine fish of the family Sillaginidae, the smelt-whitings. It is a slender, slightly compressed fish that is very similar to other species of Sillago, with detailed spine, ray and lateral line scale counts needed to distinguish the species between its nearest relative Sillago analis. The sand whiting is distributed along the east coast of Australia from Cape York south to Tasmania, as well as Lord Howe Island and New Caledonia in the Pacific Ocean.
Crab meat or crab marrow is the meat found within a crab, or more specifically in the leg of a crab. It is used in many cuisines around the world for its soft, delicate and sweet flavor. Crab meat is low in fat and provides approximately 340 kilojoules (82 kcal) of food energy per 85-gram (3 oz) serving. Brown crab, blue crabs, blue swimming crabs, and red swimming crabs are among the most commercially available species of crabmeat globally.
Ovalipes australiensis is a species of crab found in southern Australia. Its range extends from Western Australia to Queensland, including Tasmania. It is fished commercially and recreationally, although it is not as important as the blue swimmer or mud crab.
Crab fisheries are fisheries which capture or farm crabs. True crabs make up 20% of all crustaceans caught and farmed worldwide, with about 1.4 million tonnes being consumed annually. The horse crab, Portunus trituberculatus, accounts for one quarter of that total. Other important species include flower crabs, snow crabs (Chionoecetes), blue crabs, edible or brown crabs, Dungeness crab, and mud crabs, each of which provides more than 20,000 tonnes annually.
This page is a list of fishing topics.
Callinectes similis, sometimes called the lesser blue crab or dwarf crab, is a West Atlantic species of blue crab. It was described by Austin B. Williams in 1966.
Portunus sayi, the sargassum swimming crab, is a species of pelagic crab in the family Portunidae. It is found in the western Atlantic Ocean and the Caribbean Sea where it makes its home among floating mats of Sargassum seaweed. It was named in honour of the American naturalist Thomas Say.
Charybdis natator, the ridged swimming crab, wrinkled swimming crab or rock crab, is a widespread Indo-Pacific species of swimming crab from the genus Charybdis. It gets its name from the ridges on the dorsal surface of the carapace. It is a crab species which is of minor importance in fisheries.
Chaceon quinquedens, commonly known as the red deep-sea crab, but sold as Atlantic deep sea red crab, or simply Atlantic red crab or red crab, is a crab that lives in the Atlantic Ocean off the East Coast of the United States and Canada, from North Carolina to Nova Scotia, and in the Gulf of Mexico.
Portunus segnis, the African blue swimming crab, is a species of crustacean, a swimming crab belonging to the family Portunidae. While native to the western Indian Ocean, it is also invasive in the Mediterranean. It is thought to have come through the Suez Canal from the Red Sea but it may have been transported by ships.
Portunus armatus is a species of crustacean, a swimming crab in the family Portunidae found in Australia and eastwards to New Caledonia. Common names include blue swimmer crabs, Blue manna, Blueys, and Jennies. The species was originally considered as a geographic variation of Portunus pelagicus, however in 2010 the Portunus pelagicus species was reviewed using DNA, as well as physical characteristics including measurements and four species recognised: Portunus pelagicus, Portunus armatus, Portunus reticulatis and Portunus segnis. The range of Portunus armatus overlaps with Portunus pelagicus in the Northern Territory of Australia.
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