Author: Rahul Paik
DOI Link: https://doi.org/10.70798/Bijmrd/03100008
Abstract: This study examined the spatial patterns of small indigenous freshwater fish (SIFF) diversity across major river systems of West Bengal. Field surveys were conducted between 2022 and 2024 across 12 representative districts covering the Ganges–Hooghly, Bhagirathi–Madhumati, Teesta, Damodar, and lower coastal river systems. Standardized multi-habitat sampling (cast netting, seine, electrofishing where permitted, and local fisher interviews) yielded 78 SIFF taxa belonging to 14 families. Species richness and diversity indices (Shannon–Wiener H′, Simpson D, Pielou’s evenness J′) were calculated for each district and river reach. Geospatial analysis using GIS and river-network based interpolation identified clear longitudinal and lateral gradients in diversity: headwater and midreach wetlands supported higher species richness and endemism, while lower reaches near urbanized and agricultural areas showed reduced diversity and altered community composition. Multivariate analyses (NMDS, cluster analysis, and redundancy analysis — RDA) revealed that habitat heterogeneity, water quality (dissolved oxygen, turbidity, conductivity), and land-use patterns were the principal correlates of SIFF diversity. The study concluded that conservation priorities should target midreach floodplain wetlands and less-disturbed tributaries; community-based management and restoration of riparian buffers were recommended. Findings were discussed in the context of regional conservation and fisheries management.
Keywords: Small Indigenous Freshwater Fishes; West Bengal; River Systems; Biodiversity; Gis; Spatial Patterns; Shannon–Wiener Index; Habitat Heterogeneity; Conservation.
Page No: 61-71