Question

Fish species diversity is significantly lower in reservoirs than rivers.

Answer 1

Reservoir water is stagnent in nature, so less mixing of oxygen,more polluted, high concentration of bacterias because break in the natural flow of river and cycle.

Local fishes and species not able to survive in artificial conditions or regions where disturbance in level of water. No vegetation below and along the reservoir system….less availability of food. High sediment loaded areas.

But, in rivers natural flow maintains the all cycle+ purity of water leads to more fish in river in compare to reservoir.