Question 69 from UPSC CSE 2014 - Environme nt

Question

Other than poaching, what are the possible reasons for the decline in the population of Ganga River Dolphins?
1. Construction of dams and barrages on rivers
2. Increase in the population of crocodiles in rivers
3. Getting trapped in fishing nets accidentally
4. Use of synthetic fertilizers and other agricultural chemicals in crop-fields in the vicinity of rivers
Select the correct answer using the code given below.

IASCODEX · Accepted Answer

Correct Option: C. 1, 3, and 4 only

Strategy: Evaluate each statement's plausibility by cross-referencing with known threats to dolphins. Eliminate options that include non-significant threats, such as an increased crocodile population, to determine the correct answer.

Key Info: **About the Ganga River Dolphin**
The Ganga River Dolphin (Platanista gangetica), also known as the 'Susu,' is an endangered freshwater cetacean endemic to the Indian subcontinent, primarily inhabiting the Ganges-Brahmaputra-Meghna and Karnaphuli-Sangu river systems.

**Major Threats**
- Habitat fragmentation from construction of dams, barrages, and other riverine structures, which obstruct free movement and disrupt migratory and breeding patterns.
- Accidental capture or entanglement in fishing nets (bycatch), frequently leading to injury or mortality.
- Pollution from intensive agriculture, notably runoff containing synthetic fertilizers and chemical pesticides, contaminates aquatic food webs and leading to habitat degradation.
- Other key threats include water abstraction, untreated urban and industrial effluents, and increased boat traffic resulting in injuries.

**Conservation Status and Natural Predators**
Natural predators such as crocodiles do not pose a statistically significant threat, as ecological studies show long-term coexistence in Indian rivers without major dolphin population impact. The Ganga River Dolphin is protected under Schedule I of the Wildlife (Protection) Act, 1972, and has been declared India's National Aquatic Animal. Conservation efforts are spearheaded by the National Mission for Clean Ganga and various state and central government initiatives.

IASCODEX · Answer

Option A: 1 and 2 only

IASCODEX · Answer

Option B: 2 and 3 only

IASCODEX · Answer

Option D: 1, 2, 3, and 4