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Glyphis gangeticus

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA CHONDRICHTHYES CARCHARHINIFORMES CARCHARHINIDAE

Scientific Name: Glyphis gangeticus
Species Authority: (Müller & Henle, 1839)
Common Name(s):
English Ganges Shark
Taxonomic Notes: Carcharhinus murrayi (Gunther 1887) is a possible junior synonym of this species. This is uncertain however, as the holotype and only known specimen has been misplaced. Also, most literature records and specimens labeled as this species are in fact bull sharks Carcharhinus leucas or other Carcharhinid species. However, after an extensive 10-year search, a few specimens were caught in 1996 in the Ganges River (Compagno 2002).

Assessment Information [top]

Red List Category & Criteria: Critically Endangered A2cde; C2b ver 3.1
Year Published: 2007
Date Assessed: 2007-03-01
Assessor(s): Compagno, L.J.V.
Reviewer(s): Valenti, S.V. & Gibson, C.G. (Shark Red List Authority)
Justification:
The elusive Ganges shark is a freshwater riverine and possibly inshore marine and estuarine shark. Originally known only from three museum specimens, collected in the 19th century from fresh water in the lower reaches of the Ganges-Hooghly river system. It has been and is currently being fished in the Ganges-Hooghli river system, although the details are little known. Other probable threats include overfishing, habitat degradation from pollution, increasing river utilization and management, including construction of dams and barrages (Compagno 1997). This species was originally assessed as Critically Endangered on the 1996 Red List. It appears to be restricted to a very narrow band of habitat that is heavily impacted by human activity, and in the absence of a conclusive published study to show that the situation has changed, this assessment remains Critically Endangered.
History:
1996 Critically Endangered (Baillie and Groombridge 1996)
1996 Critically Endangered (Baillie and Groombridge 1996)
1996 Critically Endangered
1996 Critically Endangered

Geographic Range [top]

Range Description: This species is known only from the lower reaches of the Ganges-Hooghli river system, West Bengal, India. It possibly occurs in other river systems in the area. Could also occur in shallow marine estuaries although there are no verified marine records of this species to date.

Traditionally, this species has been assigned a wide range in the Indo-West Pacific, but this was found to be mostly based on other species of requiem sharks, particularly members of the genus Carcharhinus (Compagno 2005).
Countries:
Native:
India
FAO Marine Fishing Areas:
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: Originally known only from three museum specimens (one each in the Museum National d'Histoire Naturelle, Paris, Humboldt Museum, Berlin and Zoological Survey of India, Calcutta), all of which were collected in the nineteenth century. There were no records between 1867 until 1996, although 1996 records have not been confirmed as Glyphis gangeticus. A specimen collected 84 km upstream of the mouth of the Hooghli River, at Mahishadal in 2001 has been identified as Glyphis gangeticus but on photographs of the jaw only (Compagno in prep).
Population Trend: Decreasing

Habitat and Ecology [top]

Habitat and Ecology: This is a little known species that is yet to be adequately described (Martin 2005). Size at maturity is estimated at about 178 cm TL (Compagno 2005), maximum size at about 204 cm TL and size at birth at 56 to 61 cm TL (Compagno 2005). The habitat of this species is thought to be fresh water in the lower reaches of the Ganges-Hooghly River system, possibly also shallow marine estuaries but there are no verified marine records of this species. The small eyes and slender teeth of this shark suggest that it is primarily a fish-eater and is adapted to turbid water such as occurs in the Ganges River and the Bay of Bengal (Compagno 1997). The eyes of G. gangeticus are tilted dorsally rather than laterally or ventrally, as in most carcharhinids, suggesting that this species may swim along the bottom and scan the water above it for potential prey back-lit by the sun (Compagno 1984). However, Roberts (2005) reports that G. gangeticus in the Bay of Bengal feed heavily on dasyatid stingrays, which spend much of their time on the bottom. Glyphis gangeticus is probably viviparous (Compagno et al. 2005). It has been nominally implicated in numerous attacks on humans in the Ganges but since C. leucas occurs in the same river system this cannot be proven at present and it is possible that C. leucas was involved in most of, if not all, of the attacks (Compagno in prep).
Systems: Freshwater; Marine

Threats [top]

Major Threat(s): Historically, and is currently fished in the Ganges-Hooghly river system, although the details are not well known (Compagno 2005). It is caught by gillnet and appears in the international trade in shark jaws as curios (M. Harris pers. comm.), and probably also in the oriental fin trade and is consumed locally for its meat (Compagno 2005). There are major fisheries for sharks in India and large inshore carcharhinids, including Glyphis species, are readily targeted (L.J.V. Compagno pers. obs). Other probable threats include overfishing, habitat degradation from pollution, increasing river utilization and management, including construction of dams and barrages (Compagno 1997). A few jaws of what is apparently this species have been observed in international trade during recent years (L.J.V. Compagno pers. obs.), to testify that it is not extinct, however there is no information to suggest that the population status of this species has changed. There is an urgent need for a detailed survey of the shark fisheries of the Bay of Bengal.

Conservation Actions [top]

Conservation Actions: In 2001, the Indian government banned the landing of all species of chondrichthyan fish in its ports, although shortly afterwards, this ban was amended and now the Ganges shark Glyphis gangeticus is one of just ten species of chondrichthyans protected under Schedule I, Part II A of the Indian Wildlife (Protection) Act, 1972 (Government of India Ministry of Environment and Forests 2006). However, the effectiveness of this measure is unknown and these regulations may be difficult to enforce, with a diffuse but widespread artisanal fishery on a major river system for local consumption as well as international trade.

Citation: Compagno, L.J.V. 2007. Glyphis gangeticus. The IUCN Red List of Threatened Species. Version 2014.3. <www.iucnredlist.org>. Downloaded on 26 November 2014.
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