Other than poaching, what are the possible reasons for the decline in the population of Ganges 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.

1. 1 and 2 only
2. 2 and 3 only
3. 1, 3 and 4 only
4. 1, 2, 3 and 4

Explanation

Option (c) is correct

• Construction of dams and barrages on rivers: These structures fragment river habitats, obstruct dolphin movement, and alter the natural flow of rivers, significantly affecting their population.
• Increase in the population of crocodiles in rivers: ‘Susu’ shares its habitat with crocodiles (gharials), turtles and wetland birds, many of which are fish eaters and are potential competitors with dolphins
• Getting trapped in fishing nets accidentally: Dolphins often get entangled in fishing nets, leading to injuries or death.
• Use of synthetic fertilizers and other agricultural chemicals in crop fields near rivers: Agricultural runoff containing synthetic fertilizers and pesticides pollutes river water, degrading the dolphins’ habitat and affecting their prey availability.

Answer: (c) 1, 3 and 4 only; Difficulty Level: Easy