Ganges shark
2008/9 Schools Wikipedia Selection. Related subjects: Insects, Reptiles and Fish
| Ganges shark | ||||||||||||||||
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 Critically Endangered ( IUCN 2.3) |
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| Glyphis gangeticus ( Müller & Henle, 1839) |
The Ganges shark, Glyphis gangeticus, is a rare species of fresh water shark that dwells in the Ganges River. It should not be confused with the Bull shark, which also inhabits the Ganges River and is sometimes referred to as the Ganges shark.
Appearance
In its external appearance, G. gangeticus is a typical requiem shark. It is stocky, with a broadly rounded snout and small eyes. The first dorsal fin is over the last third of the pectoral fins, with a free rear tip that is well in front of the pelvic fins. The second dorsal fin is much smaller than the first, but is still relatively large. The anal fin is slightly smaller than the second dorsal fin. The pectoral fins are broad and falcate. A longitudinal upper precaudal pit is present, but the interdorsal ridge is absent.
The shark tends to have a uniform gray to brownish coloration, with no discernible pattern or markings. (aka) river shark
Distribution
The Ganges shark, as its name suggests, is largely restricted to the rivers of Eastern and North-Eastern India, particularly the Hooghly River of West Bengal.The Ganges, Brahmaputra, Mahanadi in Assam, Bihar and Orissa respectively. Bengalis call it Baagh Maach which means tiger fish. It is typically found in the mid to lower reaches of a river.
Biology
The shark, though poorly documented, is known to inhabit only freshwater, inshore marine and estuarine systems. Its feeding habits are unknown. Its maximum size is probably in the area of 2 m. It is probably viviparous, measuring 55 to 60 cm at birth.
A related species is the speartooth shark, Glyphis glyphis, although its distribution is different.
Endangerment
The Ganges shark is believed to be seriously endangered.
Danger to humans
The shark appears to pose a threat to humans, but this has not been proven. Though some consider the Ganges shark to be "extremely dangerous", it has so far been impossible to separate its attacks from those of bull sharks.(Allen, 107) Most likely the shark is a specialized species that feeds primarily on small fish. Amongst deadly sharks inhabiting the Ganges, the bull shark represents a greater definite danger than this extremely endangered and elusive species. According to the International Union for Conservation of Nature and Natural Resources, the Ganges shark is one of 20 sharks on the "Red List" of endangered shark species. (from the San Diego Union-Tribune, August 31, 2006, p. E8). It has been known to attack small land mammals which it chances upon and also take swipes at humans, though it wouldn't really pose a real threat to a full grown human. It forms a vital part of the rivers ecosystem. Most of the Eastern and North-eastern Indian rivers are prone to flooding. This causes widespread loss of animal and human lives. These sharks scavenge the carcasses and help keep the river clean. However, widespread and rampant fishing has seriously depleted the population of these sharks. Their oil, along with that of the Gangetic Dolphin is highly sought after.