Triaenodon obesus

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA CHONDRICHTHYES CARCHARHINIFORMES CARCHARHINIDAE

Scientific Name: Triaenodon obesus
Species Authority: (Rüppell, 1837)
Common Name(s):
English Whitetip Reef Shark
Synonym(s):
Carcharias obesus Rüppell, 1837

Assessment Information [top]

Red List Category & Criteria: Near Threatened ver 3.1
Year Published: 2005
Date Assessed: 2005-10-01
Assessor(s): Smale, M.J.
Reviewer(s): Musick, J.A. & Fowler, S.L. (Shark Red List Authority)
Justification:
This assessment is based on the information published in the 2005 shark status survey (Fowler et al. 2005).

The Whitetip Reef Shark (Triaenodon obesus) has a widespread distribution in tropical and subtropical Indian and Pacific Oceans. The species is commonly found between 10–40 m around coastal reefs, divers frequently see it resting in caves by day; it is most common in areas of high relief coral and caves. Formally it was abundant over coral reefs, these sharks' numbers are at lower levels than those found prior to widespread expansion of fishing in the past 20 years. The species' restricted habitat, depth range, small litter size and moderately late age at maturity suggest that with increasing fishing pressure this species may become threatened.

Geographic Range [top]

Range Description:The Whitetip Reef Shark is wide ranging in the Indo-Pacific. It occurs along the east coast of Africa from South Africa to Red Sea, Indian Ocean islands, northern Indian Ocean, including India, Sri Lanka, Myanmar, Vietnam, the Philippines, Australia, New Guinea and Polynesia, Melanesia, Micronesia to the Hawaiian Islands and Pitcairn group. The species is also found in the eastern Pacific, Cocos Islands, Galapagos and Panama to Costa Rica (Compagno 1984b). It is found in shallow tropical waters from about 1 m down to 330 m depth, but mainly between 10-40 m (Randall 1977).
Countries:
Native:
American Samoa (American Samoa); Australia; Christmas Island; Cocos (Keeling) Islands; Comoros; Cook Islands; Costa Rica; Djibouti; Egypt; Eritrea; Fiji; French Polynesia; Guam; India; Kenya; Kiribati; Madagascar; Maldives; Marshall Islands; Mauritius; Mayotte; Mozambique; Myanmar; Nauru; New Caledonia; New Zealand; Niue; Norfolk Island; Northern Mariana Islands; Palau; Panama; Philippines; Pitcairn; Réunion; Samoa; Saudi Arabia; Seychelles; Solomon Islands; Somalia; South Africa; Sri Lanka; Sudan; Tanzania, United Republic of; Tonga; Tuvalu; United States (Hawaiian Is.); Vanuatu; Viet Nam; Wallis and Futuna; Yemen
FAO Marine Fishing Areas:
Native:
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 [top]

Population Trend: Unknown

Habitat and Ecology [top]

Habitat and Ecology: Whitetip Reef Sharks are closely associated with coral reefs in clear, tropical waters. Primarily nocturnal, they shelter in caves by day, often communally. They often return to a home cave for periods of days, weeks or more (Randall 1977). Active at night, they hunt fish and other prey, often in caves and crevices. Maturity is attained at about 105 cm, although a mature male of 95 cm and a pregnant female of 102 cm have been recorded in the Maldives (Anderson and Ahmed 1993). Mating has been recorded in the wild by Tricas and Le Feuvre (1985) and pups are born at 52-60 cm after a gestation period of at least five months. Litter size has been recorded as 2-3 in Madagascar (Fourmanoir 1961, Last and Stevens 1994) and 1-5 elsewhere (Randall 1977, Last and Stevens 1994).

Growth is slow in the wild, estimated at 2.1-4.2 cm year-1 (Randall 1977), and they may attain sexual maturity at eight to nine years and live to about 16 years (Randall 1977, Smith et al. 1998). Maximum size is around 200 cm TL but adults are very rare over 160 cm (Compagno in prep. b).
Systems: Marine

Threats [top]

Major Threat(s): Taken in line and net trawl fisheries operating in shallow reef areas, this shark has been recorded as part of the multi-species shark catch taken by tropical fisheries, e.g. Barnett (1996), Hayes (1996) and Keong (1996). Although its life history pattern suggests a moderate capacity for rebound (Smith et al. 1998), heavy fishing pressure inshore and lack of management plan in most places suggest that this species may be under threat in heavily fished areas, including remote tropical reefs (Anderson et al.1998).

Conservation Actions [top]

Conservation Actions: No specific management or conservation plans are known to exist for this species and it must be regarded as potentially under threat from continuing tropical multi-species fisheries. Marine reserves of appropriate size and locality could protect this species, given the pattern of residency shown by Randall (1977). Its distribution in clear waters over coral reefs makes this species ideal for non-consumptive use in the form of tourism diving, as has been shown in a preliminary analysis by Anderson and Ahmed (1993).

Bibliography [top]

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.

Barnett, R. 1996. The shark trade in mainland Tanzania and Zanzibar. The World Trade in Sharks: a Compendium of TRAFFIC?s regional studies, pp. 375?411. TRAFFIC Network, Cambridge, 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.

Compagno, L.J.V. in prep. B. Sharks of the World. An annotated and illustrated catalogue of the shark species known to date. Volume 3. Carcharhiniformes. FAO, Rome.

Fourmanoir, P. 1961. Requins de la Côte Ouest de Madagascar. Memoires de L?Institut Scientifique de Madagascar. Série F. Oceanographie. ORSTOM. Tome IV.

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.

Hayes, E. 1996. The Oceania region?s harvest, trade and management of sharks and other cartilaginous fish: an overview. in TRAFFIC Network. The World Trade in Sharks: a Compendium of TRAFFIC?s regional studies, pp. 643?650. TRAFFIC Network, Cambridge, UK.

Keong, C.H. 1996. Shark fisheries and trade in sharks and shark products in Southeast Asia. The World Trade in Sharks: a Compendium of TRAFFIC?s regional studies. Volume II, pp. 807?945. TRAFFIC Network, Cambridge, UK.

Last, P.R. and Stevens, J.D. 1994. Sharks and Rays of Australia. CSIRO, Melbourne, Australia.

Randall, J.E. 1977. Contribution to the biology of the whitetip reef shark (Triaenodon obesus). California Wild (formerly known as Pacific Science) 31(2): 143?164.

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.

Tricas, T.C. and Le Feuvre, E.M. 1985. Mating in the white-tip shark Triaenodon obesus. Marine Biology 84: 233?237.


Citation: Smale, M.J. 2005. Triaenodon obesus. In: The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 01 August 2014.
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