Authors
1
Department of Environmental Science, Integral University, Kursi Road Lucknow, Uttar Pradesh, India
2
Amrit Campus, Tribhuvan University, Thamel, Kathmandu, Nepal
10.22092/ijfs.2024.131390
Abstract
Nepal has a diverse geography, ranging from an altitude of 60 m to the world's highest peaks at 8849 m. Fish diversity has been observed to extend up to an elevation of 3600 m. With its intricate topography, fluctuating climatic conditions, and abundant water resources, the region exclusively comprises freshwater habitats spanning 745,000 ha. These habitats include rivers, lakes, ponds, marshes, reservoirs, and irrigated rice fields. There are roughly 6,000 rivers and creeks in the country (194,471 km² drainage area). Four major river systems, namely Koshi, Gandaki, Karnali, and Mahakali, originate from the upper Himalayas at an altitude greater than 5000 m above sea level and drain about 75% of the country. Freshwater fishes are often overlooked in biodiversity conservation efforts, leading to a significant decrease in fish diversity, particularly in densely populated urban areas and wetlands in the southern plains of Nepal. The decrease in fish diversity is likely linked to inadequate prioritization, funding, and human resources allocated to fish conservation. According to the literature and FishBase database records, the freshwater river system in Nepal contains a total of 255 fish species from 12 orders, 41 families, and 124 genera. This includes 15 fish species that are unique to Nepal and 15 that are not native to the region. Additionally, 34 fish species in this system are considered threatened and have been listed under the IUCN Red List. These fish have pronounced vertical dispersion throughout the country and horizontal distribution within the area and continent, displaying diverse adaptations. This research specifically examines the fluctuations in water quality and the range of fish species, together with their conservation status in the rivers of Nepal.
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