Kadam Bihari, Chandra Pal Singh, Radhakrishnan K.V., Jyoti Saroj, Dinesh Kumar, Lavkush, Jay Kumar, Satyendra Kumar and Gaurav Mishra
Abstract
The study investigates the ichthyofaunal diversity and environmental correlations of the Sai River in Uttar Pradesh, India, focusing on spatial and seasonal variations in fish composition and abundance. Increasing anthropogenic pressures and the presence of exotic species have raised concerns about biodiversity loss, making regular monitoring and conservation strategies essential for sustaining the ecological balance of river. Fish samples were collected from three sites along the Sai River and analyzed for taxonomic composition across orders, families, and genera. Diversity was quantified using indices such as Shannonâs Diversity Index, Margalefâs Index, Simpsonâs Index, Dominance Index, and Evenness Index. Seasonal variations were assessed across winter, pre-monsoon, and monsoon periods, while correlation analyses were used to evaluate relationships between fish abundance and environmental parameters including rainfall, relative humidity, minimum temperature, water transparency, and total dissolved solids (TDS). A total of 39 fish species representing 8 orders, 16 families, and 28 genera were identified, with Cypriniformes as the dominant order and Cyprinidae as the largest family. Diversity indices indicated a highly diverse and evenly distributed fish community, with Shannonâs Index (3.56), Margalefâs Index (7.97), Simpsonâs Index (0.96), Dominance Index (0.076), and Evenness Index (0.90). Species richness was highest during winter and pre-monsoon, while monsoon flooding and habitat disturbances reduced diversity. Correlation analysis showed that rainfall had the strongest positive influence on fish abundance (0.396â0.553), followed by relative humidity and minimum temperature, while water transparency (0.70-0.85) and TDS (0.52-0.56) were also strongly correlated. The occurrence of exotic species and anthropogenic disturbances underscore the need for immediate conservation interventions to protect the riverâs biodiversity.