Carcharhinus amboinensis (Southwest Indian Ocean subpopulation)
|Scientific Name:||Carcharhinus amboinensis (Southwest Indian Ocean subpopulation)|
|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 information in the 2005 shark status survey (Fowler et al. 2005).
Pigeye Shark (C. amboinensis) is sporadically distributed in the Indo-West Pacific, which may, in part, be due to an inability to distinguish it from other members of the genus Carcharhinus. Where fisheries data are available, this species constitutes a very small component of the catch, suggesting that it may not be common. Natal Sharks Board data demonstrate a significant declining trend in catches from 1978–98, and a decrease in mean length in the southwest Indian Ocean. The apparently sporadic distribution and low abundance of this shark suggests that it may be unable to sustain heavy, localised fishing pressure, and shark fisheries are intensifying in the Indo-Pacific.
|Previously published Red List assessments:|
|Range Description:||This subpopulation occurs in the Southwest Indian Ocean from Madagascar, Mozambique and South Africa.|
Native:Madagascar; Mozambique; South Africa
|FAO Marine Fishing Areas:|
Indian Ocean – western
|Range Map:||Click here to open the map viewer and explore range.|
|Current Population Trend:||Unknown|
|Habitat and Ecology:||The following information, unless otherwise acknowledged, is based on studies by Stevens and McLoughlin (1991) in northern Australia and Cliff and Dudley (1991) in KwaZulu-Natal, South Africa.|
Males mature at about 210 cm and females at 215–220 cm. The largest Australian individuals were a 231 cm male and a 242 cm female; in South Africa they were a 238 cm male and a 245 cm female. Fourmanoir (1961) recorded a 280 cm female from west Madagascar. Size at birth is 60–75 cm. In Australia the largest embryo was 59 cm and the smallest free-swimming individual was 66 cm. In South Africa the smallest free-swimming individual was 75 cm (Bass et al. 1973) and the largest embryo 79 cm. These findings imply that there may be a regional difference in size at birth. Litter sizes range from 3–13, averaging five in South Africa and nine in Australia. In South Africa gestation appears to be about 12 months, with mating in January–February and term embryos found in December–January. Five out of eight South African mature females were pregnant. Data from Australia indicated a nine-month gestation, with birth in November–December. In both studies males and females were sampled in equal numbers.
In South Africa, the Pigeye Shark feeds on teleosts (62% frequency of occurrence), elasmobranchs (45%), crustaceans (13%) and cephalopods (12%). Most of the prey were demersal, associated with soft bottoms; Australian sharks had similar diets. Tag returns from juveniles in Australia indicated that their movements are relatively localised (up to 60 km), while two larger sharks moved 240 and 1,080 km (Last and Stevens 1994). On the east coast of South Africa, two tagged sharks were recaptured after 76 and 320 days, 23 and 84 km from their respective tagging localities. Based on catches in the nets that protect the swimming beaches of KwaZulu-Natal, this species is often solitary and does not appear to swim in large packs. No information is available on age and growth.
|Major Threat(s):||This species constituted 0.5 % (16 specimens) of the annual shark catch in the nets protecting swimming beaches in KwaZulu-Natal. The catch rate fluctuated at about 0.4 sharks per km of net per year between 1978–1990; data from the early years of this fishery (1952–1977) are not available. Richards Bay, the northernmost netted beach, where nets were introduced in 1981, had the highest catch of this species (annual average six, range 0–25). At this locality there was a significant decline in catch rates (Cliff and Dudley 1991), suggesting highly localised depletion.|
|Conservation Actions:||There are no known conservation and management initiatives.|
|Citation:||Cliff, G. 2009. Carcharhinus amboinensis (Southwest Indian Ocean subpopulation). The IUCN Red List of Threatened Species 2009: e.T39543A10246694.Downloaded on 19 September 2017.|
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