Gangetic dolphins

Subject :Environment

Section: Species in news

Context:

Details:

The dolphins were found dead at the Sangat Ghat (bank of river Ganga) near Aunta in Mokama, about 90 km from Patna.
Both Gangetic dolphins were killed due to the ongoing mechanised dredging to deepen the riverbed.

About Gangetic dolphins:

The Ganges river dolphin (Platanista gangetica) is a species of toothed whale classified in the family Platanistidae.
t lives in the Ganges and related rivers of South Asia, namely in the countries of India, Nepal, and Bangladesh.
It is related to the much smaller Indus river dolphin which lives in the Indus River in Pakistan and the Beas River of northwestern India.
It is also known by the name susu (popular name) or “Sisu” (Assamese language) and shushuk (Bengali).
The Ganges river dolphin has been recognized by the Government of India as its National Aquatic Animal and is the official animal of the Indian city of Guwahati.
Its first occurrence, within the Hooghly River, was documented by William Roxburgh.
The Gangetic river dolphin is one of four freshwater dolphin species worldwide.
The other three are found in the Yangtze River in China (now extinct), the Indus River in Pakistan and the Amazon River in South America.

Threats:

Dolphins are frequently targeted by poachers for their skin and oil. There is a huge demand for this mammal’s meat and fat.
Other threats include:
- Natural habitat destruction
- Fishing and poaching
- Dredging and large-scale construction of dams
- Large-scale vessel movement and related pollution
- Oil spills and other river pollutants
- Lack of prey base due to large-scale fishing, entangled in fishing net, etc.

Characteristics:

It is blind and finds its way and prey in river waters through echolocation.
Ganges river dolphins use echolocation to find food. They eat crustaceans such as prawns and fish including carp, mahseer, and even sharks such as the Ganges shark (Glyphis gangeticus). They may also take birds and turtles.
Bihar is home to around half of India’s estimated 3,000 Gangetic dolphins.

Protection status:

Gangetic dolphin is protected under Schedule I of the Wild Life (Protection) Act (WPA), 1972.
Under WPA, special instructions are provided on how to deal with Schedule I animals.
There are provisions for a three-year jail term and a fine of Rs 3,000-25,000 for possessing any body part of an animal listed in Schedule I. The forest officials are accountable and responsible for this.
IUCN red list: Endangered

Role in the ecosystem:

The presence of dolphins was a sign of a healthy riverine ecosystem.
Dolphins prefer water that is at least five-eight feet deep.
They are usually found in turbulent waters, with enough fish for them to feed on.
Gangetic dolphins live in zones with little or no current, which helps them save energy. On sensing danger, they can dive into deep waters.
The dolphins swim from the no-current zone to the edges to hunt for fish and return, Sharma recalled.