Portunus segnis

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Portunus segnis
Portunus segnisCCO.jpg
African Blue Swimming Crab (Portunus segnis) Praia Do Bilene: In the Coastal lake of Bilene, Mozambique
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. segnis
Binomial name
Portunus segnis
(Forskål, 1775)
Synonyms [1]
  • Cancer segnisForskål, 1775
  • Portunus mauritianus Ward, 1942

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. [2]

Contents

Taxonomy

Portunus segnis was first formally described in 1775 as Cancer segnis by the Swedish-speaking Finnish explorer, orientalist, naturalist, and an apostle of Carl Linnaeus Peter Forsskål with the type locality given as “Mari Rubro”, the Red Sea. [1] [3] It has been classified within the subgenus Portunus by some authorities. [1] Until a review of the genus Portunus in 2010 P. segnis was considered to be a junior synonym of Portunus pelagicus . [4] The specific name segnis means “slow”, “torpid”, “lazy”, “unenergetic”, “tardy” or “inactive”, [5] and Forskål described it as proceeding slowly in water ("tarde procedit in aqua"). [3]

Description

Portunus segnis males have a dark olive green blue carapace marked with numerous pale white spots on especially towards the rear and along the sides. These spots typically do not join to create reticulated bands but if these bands are present then it is usually thinner in the closely related P. pelagicus. The females are similar to the males except that the tips of their legs are red with a brownish red tinge rather than being blue tinged with intense rusty red. The largest specimen recorded was an egg bearing female which measured 187.8 mm × 84.3 mm (7.39 in × 3.32 in). [4]

Distribution and habitat

Portunus segnis is found in the western Indian Ocean from the eastern African coast and the Red Sea east to Pakistan and south to Madagascar and Mauritius. They were first recorded in the Mediterranean in 1898 at Port Said in Egypt, one of the first Lessepsian migrants to be recorded in that sea. It has now spread as far west as Italy and the Gulf of Gabes in Tunisia. [4]

Portunus segnis occurs largely in coastal waters in seagrass beds and mangroves. it is often encountered under rocks and in rock pools, as well as on sand or mud seabeds. They are most abundant at depths between 2 and 15 m (6 ft 7 in and 49 ft 3 in). The small juveniles occur at depth of less than 1 m (3 ft 3 in) while the females move to deeper water to spawn. [6]

Biology

The diet of Portunus segnis is seasonally dependent, with them eating crustaceans such as other crabs and shrimps more prominently in the summer, and fishes and molluscs more common in the autumn and winter. [7] Although the aforementioned animals form the major part of this species’s diet, studies have identified annelids, cnidarians, plants, and even debris in the stomach of Portunus segnis subjects. [8] This species is mainly nocturnal [4] and hunts across the surface using a zigzag pattern to find its prey, [6] spending the day buried in the sediment with only its eyes, antennae and gills clear of the substrate. In the Persian Gulf and Gulf of Oman egg-bearing females have been reported from all months of the year but their numbers peak in the Autumn. spawning peaks in the winter. [4]

This species is euryhaline, showing a wide tolerance of variations in salinity and can be found in the brackish waters in estuarine environments and in extremely salty waters such as the Great Bitter Lake in Egypt. [4]

The epizoic acorn barnacle Chelonibia patula has been collected from the exoskeleton of this species in the eastern Mediterranean Sea. In addition, a species of Octolasmis , goose barnacles belonging to the family Poecilasmatidae have been recorded on this species. Another condition of P. segnis is the “pepper spot parasite”, which is caused by protozoan hyperparasites which infect cysts containing trematodes and causes then to produce melanin. [4] One of the reasons put forward for the abundance of this species in the Mediterranean is that there are not enough octopuses to predate on them. [2]

Fisheries

Portunus segnis is fished for using shrimp trawls, seine nets and stake nets in the Persian Gulf. In 1982 over 100 tonnes was landed in Bahrain and egg-bearing females fetch the highest prices. [9]

Tunisia

Portunus segnis reached Tunisian waters in 2014. It has proved very destructive to fish stocks and fishing gear. It is now itself a species profitably fished for. Tunisian fishermen nickname it "Daesh" after the Islamic State of Iraq and the Levant because of its invasiveness and destructiveness. [10]

A new fishery to catch them has started. [10] [11] The fishermen were trained to use pots to catch them. The crabs are not eaten in Tunisia but are exported to Spain and Italy, as well as the United States and Asia. [2]

Related Research Articles

<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.

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

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.

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

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, Malaysia, Cambodia, Thailand, the Philippines, and Vietnam; and in the intertidal estuaries around most of Australia and east to New Caledonia.

<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.

<i>Charybdis</i> (crab) Genus of crabs

Charybdis is a genus of swimming crabs in the family Portunidae. It is named after the monster Charybdis of Greek mythology.

<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.

<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.

Hematodinium is a genus of dinoflagellates. Species in this genus, such as Hematodinium perezi, the type species, are internal parasites of the hemolymph of crustaceans such as the Atlantic blue crab and Norway lobster. Species in the genus are economically damaging to commercial crab fisheries, including causing bitter crab disease in the large Tanner or snow crab fisheries of the Bering Sea.

Blue crab may refer to:

<i>Cavolinia tridentata</i> Species of gastropod

Cavolinia tridentata is a species of sea butterflies, floating and swimming sea snails or sea slugs, pelagic marine gastropod molluscs in the family Cavoliniidae. It is a common species and is wide spread, being found in European waters, the Atlantic Ocean, the Caribbean Sea, the Gulf of Mexico, the Indian Ocean and in the Pacific Ocean. It lives in the photic zone of the ocean between 0 to 30m in depth.

<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>Portunus sanguinolentus</i> Species of crab

Portunus sanguinolentus, the three-spot swimming crab, blood-spotted swimming crab or red-spotted swimming crab, is a large crab found throughout estuaries of the Indian and West Pacific Oceanic countries.

<i>Melicertus kerathurus</i> Species of crustacean

Melicertus kerathurus, the striped prawn or caramote prawn is a species of tiger prawn from the family Penaeidae which occurs in the eastern Atlantic and Mediterranean Sea which is an important species in commercial fisheries. It is the type species for the genus Melicertus.

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

Charybdis hellerii, the Indo-Pacific swimming crab or spiny hands is a species of crab from the swimming crab family, the Portunidae. Its native range covers the Indian and Pacific Oceans but it has been introduced to the western Atlantic and has invaded the Mediterranean. It is a commercially exploited species in south-east Asia.

<i>Ashtoret lunaris</i> Species of crab

Ashtoret lunaris, also known as the yellow moon crab, spotted moon crab or box crab, is an Indo-Pacific species of carnivorous crab which is a member of the family Matutidae. It has been recorded in the eastern Mediterranean since 2010, likely reaching it via the Suez Canal from the Red Sea by.

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>Charybdis feriata</i> Species of crab

Charybdis feriata, the crucifix crab, is a species of swimming crab in the family Portunidae. It is found in the tropical and subtropical Indo-Pacific region.

<i>Scylla olivacea</i> Species of crab

Scylla olivacea, commonly known as the orange mud crab, is a commercially important species of mangrove crab in the genus Scylla. It is one of several crabs known as the mud crab and is found in mangrove areas from Southeast Asia to Pakistan, and from Japan to northern Australia. Along with other species in the genus Scylla, it is widely farmed in aquaculture using wild-caught stocks. They can be differentiated from other species of Scylla by having blunted spines on the dorsal distal corner of the palm (propodus) of the claw, and by the rounded frontal lobe spines with shallow separations in between the eyes.

<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. 1 2 3 Sammy de Grave (2022). "Portunus segnis (Forskål, 1775)". WoRMS. World Register of Marine Species . Retrieved 15 July 2022.
  2. 1 2 3 Rossella Santosuosso (15 July 2022). "Crab invasion: alien species goes from pest to profit – a photo essay". The Guardian. Retrieved 15 July 2022.
  3. 1 2 Forskål P. (1775). Descriptiones Animalium, Avium, Amphibiorum, Piscium, Insectorum, Vermium; quae in Itinere Orientali Observavit Petrus Forskål. Post Mortem Auctoris editit Carsten Niebuhr. Adjuncta est materia Medica Kahirina. Mölleri, Hafniae.
  4. 1 2 3 4 5 6 7 "Portunus segnis". CABI . Retrieved 16 July 2022.
  5. ↑ "segnis adjective II class". Online Latin Dictionary. Retrieved 16 July 2022.
  6. 1 2 "Portunus segnis (Forskål, 1775)". Sea Life Base. Retrieved 16 July 2022.
  7. ↑ Safaie, Mohsen (2016). "Feeding habits of blue swimming crab Portunus segnis (Forskal, 1775) in the northern coastal waters of Iran". Marine Biodiversity Records. 9 (1): 68. doi: 10.1186/s41200-016-0073-y . S2CID   5025612.
  8. ↑ Hamida, Olfa Ben Abdallah-Ben Hadj; Hamida, Nader Ben Hadj; Ammar, Rihab; Chaouch, Houda; Missaoui, Hechmi (2019). "Feeding habits of the swimming blue crab Portunus segnis (Forskål, 1775) (Brachyura: Portunidae) in the Mediterranean". Journal of the Marine Biological Association of the United Kingdom. 99 (6): 1343–1351. doi:10.1017/S0025315419000250. S2CID   182630761.
  9. ↑ Carpenter KE; Krupp F; Jones DA; Zajonz U (1997). FAO species identification field guide for fishery purposes. The living marine resources of Kuwait, Eastern Saudi Arabia, Bahrain, Qatar, and the United Arab Emirates. Food and Agriculture Organization (FAO): Rome, Italy. p. 38. ISBN   92-5-103741-8.
  10. 1 2 Jamli, Aymen (14 October 2018). "Tunisia fishermen turn tide to cash in on blue crab menace". phys.org. Retrieved 25 December 2020.
  11. ↑ "Tunisia, Carthage Crabs emerging as new source of blue swimming crab | SeafoodSource".
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