Impact of Heavy Rain and Flood on Ichthyofaunal Diversity and Distribution Pattern in River Network of Kumaon Region of Uttarakhand State, India

In the present study an attempt has been made to assess the ichthyofaunal diversity in the rivers and streams of Kumaon region of Uttarakhand state with main focus on impact of natural calamity such as heavy rain and flood. The estimated total length of major river network in Kumaon region is 1626.2 km including streams, tributaries and rivulets, which support occurrence of 31 fish species. The data of Catch Per Unit Effort (CPUE) indicated decrease in main river courses, but richness in their tributaries after flood. In main river courses, the CPUE was decreased as 0.03 kg/h to 0.32 kg/h from 0.12 kg/h to 1.28 kg/h due to heavy rain and flood condition during the month of September, 2021, while it was increased in side tributaries of these rivers as 1.84 kg/h to 3.12 kg/h from 1.14 kg/h to 2.30 kg/h after the flood. Tributaries are shelters and protected areas to the local migratory fish species during natural calamity and high turbidity in the main river course. These resources are important for ichthyofaunal diversity and sustainability of aquatic ecosystem.