Taxonomic name: Charybdis hellerii (A. Milne-Edwards, 1867) Synonyms: Charybdis (Goniosoma) merguiense (Alcock, 1899; Nobili, 1906, Chopra, 1935; Leene, 1973; Shen, 1937), Charybdis amboinensis (Leene, 1938), Charybdis merguiensis (Sakai, 1934; Barnard, 1950; Guinot, 1962), Charybdis vannamei Ward 1941, Goniosoma hellerii (A. Milne-Edwards, 1867), Goniosoma merguiense (DeMan, 1888), Goniosoma sexdentatum (De Man, 1879), Goniosoma spiniferum Common names: Indo-Pacific swimming crab (English), Ishigani New Caledonia (Japanese), New Caledonia-Ăshigani (Japanese), spiny hands (English) Organism type: crustacean Charybdis hellerii is an Indo-Pacific, portunid crab that has invaded several locations in the Mediterranean Sea, by Erythrean invasion through the Suez Canal, and the South Atlantic in the Caribbean and United States via ballast water fouling. Charybdis hellerii is a potential threat to native crab populations and benthic communities and its introduction should be avoided by adhering to ballast water management guidelines. Description Charybdis hellerii is a small crab measuring from about 5-8 cm wide. It is dark green with a light purple on the upper inner surface of palm and dark purple on dorsal surfaces of distal 4 segments of walking and swimming legs. The carapace has pale green to whitish areas on frontal, hepatic, and epibranchial regions. It is most easily identifiable by the spine on the posterior of the carpus on the fifth leg which bears its chela, or claws giving it one of its common names: spiny hands. Its dorsal carapace is naked and its anterolateral margin has 6 prominent black-tipped teeth. Its frontal region bears 6 prominent teeth, 2 inner orbitals, and 4 blunt submedians. Chela are stout with palms bearing 5 strong black-tipped spines on the distal posterior margin. Propodus also with a row of spines on the posterior margin. Adult females are typically 47 to 62 mm and adult males 74 to 83 mm carapace width (Perry, 2009; GSMFC, 2003). Occurs in: marine habitats Habitat description Charybdis hellerii inhabits the littoral zone of coastal waters with depths of up to 30-50 m. In its native range, it prefers soft bottom substrates but is also known to occur in rocky bottom areas and intertidal coral reefs. Typically found in high salinities of over 28 ppt C. hellerii exhibits cryptic behavior, taking advantage of a large variety of structured habitats such as riprap jetties, coralline ledges, mangrove roots, gravel, rocks, and dense algae with populations often limited to them (Dineen et al., 2001; Spiridonov, 1990). General impacts Charybdis hellerii may compete with native crab species and inflict changes in natural benthic communities. C. hellerii introductions may also affect crab fisheries if it displaces native species or results in the reduction of their numbers (Dineen et al., 2001). Geographical range Native Range: Andaman Islands, Australia, China, Hong Kong, India, Indonesia, Japan, Madagascar, New Caledonia (Nouvelle Caledonie), Pakistan, Philippines, Singapore, Somalia, South Africa, Sri Lanka Known introduced range: Brazil, Columbia, Cuba, Cyprus, Egypt, French Guiana, Lebanon, Mediterranean Sea, Syrian Arab Republic, Turkey, United States, Venezuela Introduction pathways to new locations Ship ballast water: Charybdis hellerii is most commonly distributed to new locations via fouling of water in ship ballast tanks as indicated by their arrivals correspondence with shipping routes and contracts (Dineen et al., 2001; Galil & Zenetos, 2002).
Local dispersal methods Natural dispersal (local): Water currents: Management information Preventative measures: Ballast water fouling is the means of introduction of Charybdis hellerii in most instances. Due to the high amount of invasive introductions by way of ballast water fouling, the International Maritime Organization (IMO) in conjunction with the Global Environment Facility and the United Nations Development Programme have established GloBallast, an organization devoted to implementing guidelines and regulations related to ballast water management. Compliance with GloBallast ballast water management guidelines is recommended to prevent the introduction of C. hellerii and other potential invasives (IMO, 2009). Nutrition Charybdis hellerii has generalized carnivorous diet allows for opportunistic exploitation of many different food sources (Dineen et al., 2001). Reproduction Sexual, oviparous, with females capable of storing sperm at least 5 months. C. hellerii experiences reproductive peaks during the winter and spring contrary to other crab species which experience reproductive peaks in summer, a strategy to minimize competition other crab species (Dineen et al., 2001) . Lifecycle stages Charybdis hellerii has an incubation period which lasts about 13 days, its zoeal development averages 40 days, and a megalopa stage that takesanother 4 days. This relatively long larval development of about 44 days facilitates wide dispersal. Its juvenile growth and maturation is relatively rapid taking about one year. This results in a short generation time a characteristic that contributes to rapid population growth. Finally, C. hellerii have high fecundity and are capable of bearing broods in rapid succession. These developmental and reproductive characteristics facilitate the potential of C. hellerii for rapid invasion of new locations (Dineen et al., 2001). Reviewed by: Paul F. Clark, Department of Zoology, The Natural History Museum, London. Principal sources: Dineen, J.E. Clark, P.F., Hines, A.H., Reed, S.A. & Walton, H.P. 2001. Life history, larval description, and natural history of Charybdis hellerii (Decapoda, Brachyura, Portunidae), an invasive crab in the western Atlantic. Journal of Crustacean Biology 21(3): 774-805 Gulf States Marine Fisheries Commission (GSMFC)., 2003. Charybdis hellerii (Milne Edwards, 1867) Ferreira, A.C., Sankarankuty, C.; da Cunha, I.M.C. & Duarte, F.T. 2001. Yet another record of Charybdis hellerii (A. Milne Edwards) (Crustacea, Decapoda) from the Northeast of Brazil. Revista Brasileira de Zoologia 18(1):357-358. Harriet Perry. 2008. Charybdis hellerii. USGS Nonindigenous Aquatic Species Database, Gainesville, FL.
Compiled by: National Biological Information Infrastructure (NBII) & IUCN/SSC Invasive Species Specialist Group (ISSG)
|
|
Last Modified: Tuesday, 7 April 2009
|