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.
Statement 1 is correct: This is a major threat. Dams fragment the river habitat, hinder migration patterns, and can disrupt prey availability for the dolphins. Statement 2 is incorrect: While competition might exist, it's not a cause of decline. A healthy river ecosystem can support both dolphins and crocodiles. Statement 3 is correct: This is a significant threat, as dolphins can get caught in fishing gear and drown. Statement 4 is correct: Runoff from agricultural lands can pollute rivers with pesticides and fertilizers. These pollutants can harm the dolphins' health and prey species. Thus 1,3, and 4 are the causes of the decline in the Ganga River Dolphins.