The Ganges Shark (Glyphis gangeticus) is one of 6 species of river shark and is often confused with another shark that is found in rivers, the bull shark. Records of human interactions with this shark, including attacks, are thought to be the case of mistaken identity. They belong to the family of requiem sharks in the order Carcharhiniformes.
Where are they found?
Unlike most sharks, the Ganges Shark is found almost exclusively in freshwater rivers. It is a True River Shark endemic to India and the Ganges River. Its habitat range is thought to include rivers in Pakistan, Myanmar, Borneo, and Java. There are no confirmed records of anyone finding this species of shark in any oceans. It has only been found within middle and lower levels of freshwater and estuarine ecosystems.
Image courtesy of Shark Sider
What do they look like?
The Ganges Shark is a medium sized stocky shark with a greyish brown body. Their appearance is similar to the much more well-known bull shark, but with some important differences.
Image courtesy of Müller & Henle/Public domain.
- They have very small eyes that, unlike most sharks, are tilted dorsally. This is believed to be an adaptation to help them scan for prey from above. Their small eyes also help them navigate the murky, muddy waters of the rivers they inhabit, and they possess a nictating membrane that helps to protect their eyes from silt and mud.
- They have a broadly rounded snout that is significantly shorter than the width of their mouth with sharp and slender teeth. Their upper set of jaws contains broad serrated teeth while their lower set has long, protruding teeth with cutting edges.
- They have 2 spineless dorsal fins and an anal fin, with the second dorsal fin being much shorter than the first.
They are a medium sized shark, growing to 70-80in in length (~6-7ft).
Image courtesy of Müller & Henle/Public domain
What do they eat?
Many of their feeding habits are unknown, but it is presumed from the shape and size of their teeth along with the position of their eyes that they feed mainly on smaller fish and rays, trawling the bottom of the river in search of prey.
Threats to the Ganges Shark:
The Ganges Shark is registered on the IUCN list as Critically Endangered. Their population has been steadily decreasing for decades. Some of the main threats that they face are overfishing, poaching, habitat degradation, increased river utilization, dam installation, and pollution. Their fins and jaws are sold in high demand in the international trade and many local fisheries hunt them for their meat, fins, and squalene.
They are protected under Schedule 1 of the Wildlife Protection Act of 1972, where any capture, killing or sale of this shark is punishable by law, but it can be hard to tell if this protection has made any impact on the populations that are still seeing a rapid decline. Implementation of these regulations can be very hard to enforce, especially when traded internationally.
River sharks are especially vulnerable to pollution. The Ganges River basin, in which this shark primarily resides, is densely populated with more than 400 million people. It is one of the most heavily polluted water systems in the world, being subject to daily disposal of industrial waste, trash and raw sewage.
With the reduction in shark populations, we often see a direct impact on marine ecosystems within that area. Sharks are apex predators that help regulate their environment by preying on other predatory fish/species. When these species are allowed to grow unchecked, they often decimate smaller prey species population, overall resulting in the degradation of the marine ecosystem.
Image courtesy of the IUCN Redlist