Why are there fewer and fewer fish in the Macha River in Nanjing?

Environmental pollution, overfishing, climate change and natural disasters.

1. Environmental pollution: With the development of cities and the growth of population, large amounts of domestic sewage and industrial wastewater are discharged into rivers, causing water quality to deteriorate and causing serious damage to the fish living environment.

2. Overfishing: In order to seek personal gain, some fishermen use prohibited fishing gear such as ground traps to conduct destructive fishing of fish. This not only destroys the habitat of aquatic life, but also leads to a significant reduction in fish populations.

3. Climate change and natural disasters: For example, extreme weather events such as heavy rains and droughts may change the water quality and flow rate of rivers, affecting the reproduction and survival of fish.