Portunus pelagicus

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Portunus pelagicus
Portunus pelagicus male.jpg
Male
Scientific classification OOjs UI icon edit-ltr.svg
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
  • Cancer pelagicusLinnaeus, 1758

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]

Contents

Description

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.

Behaviour

Portunus pelagicus feeding, Qatif, Saudi Arabia. Portunus pelagicus, Qatif 0.jpg
Portunus pelagicus feeding, Qatif, Saudi Arabia.

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.

Capture

Global capture production of Portunus pelagicus in thousand tonnes from 1965 to 2022, as reported by the FAO Blue swimming crab capture production thousand tonnes 1965-2022.svg
Global capture production of Portunus pelagicus in thousand tonnes from 1965 to 2022, as reported by the FAO

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.

StateMinimum carapaceBag limitBoat limitPossession LimitNotes
South Australia 11 cm20 (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 cm10N/A20 [13]
Western Australia 12.7 cm20 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 cmNo limitNo limitNo limit [16]
Northern Territory N/AN/AN/A30Combined total for any crab species other than mud crabs. [17]

Ecology

Male Portunus pelagicus can be territorial. Portunus pelagicus.jpg
Male Portunus pelagicus can be territorial.

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.

Cultural Significance

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".

Related Research Articles

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<i>Portunus trituberculatus</i> Species of crab

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<i>Notomithrax ursus</i> Species of crab

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<span class="mw-page-title-main">King George whiting</span> Species of fish

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.

<span class="mw-page-title-main">Sand whiting</span> Species of fish

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This page is a list of fishing topics.

<i>Callinectes similis</i> Species of crab

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.

<i>Portunus sayi</i> Species of crab

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.

<i>Charybdis natator</i> Species of crab

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.

<i>Chaceon quinquedens</i> Species of crab

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.

<i>Portunus segnis</i> Species of crab

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.

<i>Portunus armatus</i> Species of crustacean

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.

References

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  7. Lai, Joelle C Y; Ng, Peter K L; Davie, Peter J F (2010). "A revision of the Portunus pelagicus (Linnaeus, 1758) species complex (Crustacea: Brachyura: Portunidae), with the recognition of four species". The Raffles Bulletin of Zoology. 58 (2): 199–237. ISSN   0217-2445.
  8. 1 2 Nicholas Romano & Chaoshu Zeng (2007). "Ontogenetic changes in tolerance to acute ammonia exposure and associated histological alterations of the gill structure through the early juvenile development of the blue swimmer crab, Portunus pelagicus". Aquaculture . 266: 246–254. doi:10.1016/j.aquaculture.2007.01.035.
  9. "Fisheries and Aquaculture - Global Production". Food and Agriculture Organization of the United Nations (FAO). Retrieved 2024-05-06.
  10. Nicholas Romano & Chaoshu Zeng (2007). "Acute toxicity of sodium nitrate, potassium nitrate and potassium chloride and their effects on the hemolymph composition and gill structure of early juvenile blue swimmer crabs (Portunus pelagicus Linnaeus, 1758) (Decapoda, Brachyura, Portunidae)". Environmental Toxicology and Chemistry . 26 (9): 1955–1962. doi:10.1897/07-144R.1. PMID   17705664. S2CID   19854591.
  11. Nicholas Romano & Chaoshu Zeng (2007). "Effects of potassium on nitrate mediated changes to osmoregulation in marine crabs". Aquatic Toxicology . 85 (3): 202–208. doi:10.1016/j.aquatox.2007.09.004. PMID   17942166.
  12. "Blue Swimmer Crab". pir.sa.gov.au. Department of Primary Industries and Regions, South Australia. Retrieved 2016-03-19.
  13. "Bag and size limits - saltwater - NSW Department of Primary Industries". www.dpi.nsw.gov.au. Retrieved 2016-03-19.
  14. "Recreational fishing guide 2015" (PDF).
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  16. "Size, take and possession limits for tidal waters". www.daf.qld.gov.au. Retrieved 2016-03-19.
  17. "Archived copy" (PDF). Archived from the original (PDF) on 2016-03-07. Retrieved 2016-03-20.{{cite web}}: CS1 maint: archived copy as title (link)
  18. Nicholas Romano & Chaoshu Zeng (2006). "The effects of salinity on the survival, growth and haemolymph osmolality of early juvenile blue swimmer crab, Portunus pelagicus". Aquaculture . 260 (1–4): 151–162. doi:10.1016/j.aquaculture.2006.06.019.