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

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, but is of far inferior flavor[ citation needed ]. 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 [9] [10] 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 [11]
New South Wales 6 cm10N/A20 [12]
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. [13] [14]
Queensland 11.5 cmNo limitNo limitNo limit [15]
Northern Territory N/AN/AN/A30Combined total for any crab species other than mud crabs. [16]

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. [17] 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.

Related Research Articles

<span class="mw-page-title-main">Nitrate</span> Polyatomic ion (NO₃, charge –1) found in explosives and fertilisers

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.

<i>Portunus</i> Genus of crabs

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.

<span class="mw-page-title-main">Crab</span> Infraorder of decapod crustaceans

Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" (abdomen), usually hidden entirely under the thorax. They live in all the world's oceans, in freshwater, and on land, are generally covered with a thick exoskeleton, and have a single pair of pincers on each arm. They first appeared during the Jurassic Period.

<i>Callinectes sapidus</i> Species of crustacean

Callinectes sapidus, the blue crab, Atlantic blue crab, or regionally as 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.

<span class="mw-page-title-main">Portunidae</span> Family of crabs

Portunidae is a family of crabs which contains the swimming crabs. Its members include many well-known shoreline crabs, such as the blue crab and velvet crab. Two genera in the family are contrastingly named Scylla and Charybdis; the former contains the economically important species black crab and Scylla paramamosain.

<span class="mw-page-title-main">Peel-Harvey Estuarine System</span> Estuarine system south of Mandurah, Western Australia

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.

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

Notomithrax ursus, known as the hairy seaweed crab, is a spider crab of the family Majidae.

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

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.

<i>Sesarma reticulatum</i> Species of crab

Sesarma reticulatum, the purple marsh crab or simply marsh crab, is a crab species native to the salt marshes of the eastern United States.

<span class="mw-page-title-main">Crab fisheries</span> Fisheries which capture or farm crabs

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.

<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>Polybius henslowii</i> Species of crab

Polybius henslowii is a species of crab, the only species in the genus Polybius. It is a capable swimmer and feeds in open water in the north-east Atlantic Ocean and western Mediterranean Sea.

<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.

Charybdis longicollis, the lesser swimming crab, is a species of crab from the swimming crab family, the Portunidae. It has a native range which covers the north-western Indian Ocean and it has invaded the Mediterranean Sea by Lessepsian migration through the Suez Canal.

<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.

<i>Paguristes eremita</i> Species of crustacean

Paguristes eremita, the eye spot hermit crab, is a species of hermit crab in the family Diogenidae. It is found in the Mediterranean Sea.

<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

  1. "FishSource - Blue swimming crab - Java Sea".
  2. "Saving flower crabs for future generations". The Star. Retrieved 2023-06-12.
  3. "Enhancing sustainable management of the blue swimming crab fisheries in Cambodia".
  4. "Thai Blue Swimming Crab Fishery Improvement Project - a pathway to sustaining marine environment".
  5. "Wild-caught blue swimming crab in the Philippines". Monterey Bay Aquarium Seafood Watch. Retrieved December 22, 2023.
  6. "Research paper: Study of the impact of intermediaries on environmental and social outcomes and worker vulnerability in small-scale fishing and aquaculture in Indonesia and Viet Nam". 9 March 2021.
  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. 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.
  10. 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.
  11. "Blue Swimmer Crab". pir.sa.gov.au. Department of Primary Industries and Regions, South Australia. Retrieved 2016-03-19.
  12. "Bag and size limits - saltwater - NSW Department of Primary Industries". www.dpi.nsw.gov.au. Retrieved 2016-03-19.
  13. "Recreational fishing guide 2015" (PDF).
  14. "Blue swimmer crab recreational fishing". www.fish.wa.gov.au. Retrieved 2016-03-19.
  15. "Size, take and possession limits for tidal waters". www.daf.qld.gov.au. Retrieved 2016-03-19.
  16. "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)
  17. 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.