Prelims 2014 · Environment · Question 74
Other than poaching, what are the possible reasons for the decline in the population of Ganges River Dolphins?
- Construction of dams and barrages on rivers
- Increase in the population of crocodiles in rivers
- Getting trapped in fishing nets accidentally
- 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.
Answer
1, 3 and 4 only
1. Construction of dams and barrages on rivers — Correct. These fragment river habitat, alter flow, and isolate dolphin populations, which is a known cause of decline.
2. Increase in the population of crocodiles in rivers — Incorrect. This is not recognized as a major reason for the decline of Ganges River Dolphins in standard conservation literature.
3. Getting trapped in fishing nets accidentally — Correct. Accidental entanglement/bycatch in fishing gear is a significant threat to river dolphins.
4. Use of synthetic fertilizers and other agricultural chemicals in crop-fields near rivers — Correct. Agricultural runoff pollutes river water and degrades habitat, affecting dolphin survival.
Therefore, 1, 3 and 4 only are correct.