Biodiversity Status and Environmental Drivers of Ichthyofauna in Shivna River, India

Aims: This study evaluates ichthyofaunal diversity in relation to seasonal water quality variations across three monitoring stations in the Shivna River (2024-2025), employing multigear sampling and standard physicochemical analyses. Study Design:  Observational field study with seasonal sampling across three longitudinal stations. Place and Duration of Study: Shivna River, located at 24.07 ° N, 75.08 ° E, is a 102 km long stretch located in Mandsaur of Madhya Pradesh. This annual study (12 months) that covers all the seasons from June 2024-May 2025. Methodology: To evaluate the association between water chemistry and fish diversity, 2-liter surface water samples were collected the upper 30 cm using sterile PET bottles from three different study stations and analyzed for various water quality parameters according to APHA 23rd Edition (2017) standards. The Water Quality Index (WQI) determined via BIS 10500:2012 guidelines. We evaluated the fish community using PAST 4.0 to calculate Shannon-Wiener diversity (H'), Pielou evenness (J'), and Margalef richness. Finally, statistical relationships were established using SPSS 27, employing Pearson correlations (n = 27) to link species abundance and diversity with physicochemical parameters, complemented by a three-way ANOVA. Results: The Shivna River supported 32 fish species across 5 orders and 14 families. WQI deteriorated seasonally from "good" (32.13, monsoon) to "poor" (107.15, winter) and "very poor" (165.75, summer). Shannon diversity (H') declined from 2.1 (winter) to 1.4 (summer, upstream S1), with Pielou evenness (J') dropping from 0.78 to 0.52. Non-native Oreochromis increased from 18% to 32% of catch in summer. Fish diversity negatively correlated with BOD (r=-0.76, p<0.001), indicating organic pollution drives native species loss. Conclusion: Threshold-based management is essential for Shivna River conservation. Interventions are recommended when DO <6 mg/L or H' <1.6, including 10-m riparian buffers and fertigation monitoring to mitigate nutrient enrichment and protect native ichthyofauna.