Question:
There is a mass mortality of fish in a pond. What may be the reasons?
Solution:
1. Passage of pesticide rich water from crop fields.,
2. Pouring of industrial waste.
3. Pouring of hot water from an industry or thermal power plant.
4. Release of waste rich in heavy metal and mercury.
5. Blockage of fish gills by some suspended pollutant.
6. Excessive eutrophication.