|Scientific Name:||Carcharhinus amblyrhynchos|
|Species Authority:||(Bleeker, 1856)|
Carcharias amblyrhynchos Bleeker, 1856
|Red List Category & Criteria:||Near Threatened ver 3.1|
|Reviewer/s:||Musick, J.A. & Fowler, S.L. (Shark Red List Authority)|
This assessment is based on the information published in the 2005 shark status survey (Fowler et al. 2005).
The Grey Reef Shark (Carcharhinus amblyrhynchos) is a widespread, social species that formerly was common in clear, tropical, coastal waters and oceanic atolls. Its restricted habitat, site fidelity, inshore distribution, small litter size, and relatively late age at maturity, along with increasing fishing pressure suggests that this species may be under threat. Although caught in tropical multi-species fisheries, it has considerably greater value in dive tourism if protected. With time and additional data, this Near Threatened assessment may need to be revised.
|Range Description:||The Grey Reef Shark is a widespread species occurring in the central Pacific and westwards to the eastern Indian Ocean. Garrick (1982) notes his most eastern records of this species from Tuamoto Archipelago in the south and the Hawaiian Islands in the north, west through the Pacific, northern coast of Australia, Indonesia, Sumatra and west to Madagascar in the Indian Ocean, including the Seychelles and Reunion (see Compagno 1984 and Last and Stevens 1994 for maps).|
Native:Australia; British Indian Ocean Territory (Chagos Archipelago); French Polynesia (Tuamotu); Indonesia; Madagascar; Réunion; Seychelles; United States (Hawaiian Is.)
|FAO Marine Fishing Areas:||
Indian Ocean – eastern; Indian Ocean – western; Pacific – eastern central; Pacific – northwest; Pacific – western central
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||This shark has been recorded as locally highly abundant at some sites. Some local populations have been severely depleted.|
|Habitat and Ecology:||
The species is found in clear tropical waters often from 10 m to more than 50 m around coral reefs, particularly near drop-offs and passes of fringing reefs. It is more common at ancient atolls, and less common at high profile islands with extensive human habitation, or in turbid continental waters (Randall 1986, Wetherbee et al. 1997). At unexploited sites Grey Reef Sharks are one of the most common tropical reef sharks that may be found in groups or individually. Potentially dangerous when harassed, they have been shown to display stereotypical threats (Johnson and Nelson 1973, Nelson 1981, Randall 1986). Divers are advised to keep their distance and not take strobe photographs when sharks display erratic swimming.
Males mature at 120?140 cm total length (TL) and attain a size of 185 cm; females mature at about 125 cm TL and attain 190 cm (Wetherbee et al. 1997) at about seven years. Litters are small, up to six embryos (Compagno 1984b, Last and Stevens 1994, Wetherbee et al. 1997). Seasonality is uncertain because of limited data. Parturition may be in August with a nine month gestation possible in the southern hemisphere (Stevens and McLoughlin 1991). Mating and fertilisation take place in March?May (or July). Pupping appears to occur from March to July off Hawaii, suggesting a 12 month gestation, but females reproduce every other year (Wetherbee et al. 1997). Fishes form the bulk of the prey while squids, octopuses and crustaceans are less important food items (Salini et al. 1992, Wetherbee et al. 1997).
|Major Threat(s):||This shark shows high site fidelity and some local populations have been severely depleted by modest fishing pressure, as has been shown off Hawaii (Wetherbee et al. 1997). Very marked declines of sharks, including Grey Reef Sharks, have been reported in the Chagos Archipelago (Indian Ocean) between the 1970s and 1996. Shark numbers here were reduced to only 14% of the numbers found in the 1970s (Anderson et al. 1998). The quality of its coral reef habitat is threatened in many parts of the world.|
|Conservation Actions:||Smith et al. (1998) found this species to have moderate rebound potential, so it should respond positively to effective management measures. Because Grey Reef Sharks are found in clear tropical waters over coral reefs, they are ideal for non-consumptive (but much more lucrative) use in the form of tourism diving, as has been shown by Anderson and Ahmed (1993). For this reason, shark populations at some of the most important reef diving sites in the Maldives are now protected.|
Anderson, R.C. and Ahmed, H. 1993. The shark fisheries in the Maldives. FAO, Rome and Ministry of Fisheries, Male, Maldives.
Anderson, R.C., Sheppard, C., Spalding, M. and Crosby, R. 1998. Shortage of sharks at Chagos. Newsletter of the IUCN/SSC Shark Specialist Group, UK.
Compagno, L.J.V. 1984. Sharks of the World. An annotated and illustrated catalogue of shark species to date. Part II (Carcharhiniformes). FAO Fisheries Synopsis, FAO, Rome.
Fowler, S.L., Cavanagh, R.D., Camhi, M., Burgess, G.H., Cailliet, G.M., Fordham, S.V., Simpfendorfer, C.A. and Musick, J.A. (comps and eds). 2005. Sharks, Rays and Chimaeras: The Status of the Chondrichthyan Fishes. Status Survey. pp. x + 461. IUCN/SSC Shark Specialist Group, IUCN, Gland, Switzerland and Cambridge, UK.
Garrick, J.A.F. 1982. Sharks of the genus Carcharhinus. NOAA Technical Report NMFS.
IUCN. 2009. IUCN Red List of Threatened Species (ver. 2009.2). Available at: www.iucnredlist.org. (Accessed: 3 November 2009).
IUCN SSC Shark Specialist Group. Specialist Group website. Available at: http://www.iucnssg.org/.
Johnson, R.H. and Nelson, D.R. 1973. Agonistic display in the gray reef shark, Carcharhinus menisorrah, and its relationship to attacks on man. Copeia 1973: 76?84.
Last, P.R. and Stevens, J.D. 1994. Sharks and Rays of Australia. CSIRO, Melbourne, Australia.
Nelson, D.R. 1981. Aggression in sharks: Is the gray reef shark different? Oceanos 24: 45?55.
Randall, J.E. 1986. Sharks of Arabia. Immel, London, UK.
Salini, J.P., Blaber, S.J.M. and Brewer, D.T. 1992. Diets of sharks from estuaries and adjacent waters of the North-eastern Gulf of Carpentaria, Australia. Australian Journal of Marine and Freshwater Research 43: 87?96.
Smith, S.E., Au, D.W. and Show, C. 1998. Intrinsic rebound potentials of 26 species of Pacific sharks. Marine and Freshwater Research 49(7): 663?678.
Stevens, J. D. and McLoughlin, K.J. 1991. Distribution, size and sex composition, reproductive biology and diet of sharks from northern Australia. Australian Journal of Marine and Freshwater Research 42: 151?199.
Wetherbee, B.M., Crow, G.L. and Lowe, C.G. 1997. Distribution, reproduction and diet of the gray reef shark, Carcharhinus amblyrhynchos in Hawaii. Marine Ecology Progress Series 151: 181?189.
|Citation:||Smale, M.J. 2009. Carcharhinus amblyrhynchos. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 17 March 2014.|
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