Understanding enviro-climatological impact on fish biodiversity of the tropical floodplain wetlands for their sustainable management

Inland open water fisheries around the world are threatened due to growing anthropogenic pressures, climate change and overexploitation of the germplasm resources. Understanding how the floodplain wetland fish diversity responds to these unprecedented challenges is critical for developing alternative management and mitigation strategies in vulnerable wetland ecosystems. This communication elucidates the changing pattern of fish diversity in three moderately impacted tropical floodplain wetlands namely Bhomra, Mathura and Chandania in the lower Ganges basin during the year 2017–2019. Experimental fishing using gill net, drag net and cast net was carried out monthly to assess the fish diversity pattern in the three wetlands. Enviro-climatological parameters were assessed, and the important parameters influencing fish diversity were identified. Most of the critical environment parameters including pH, DO, water temperature were in the favourable range for fish. ANOVA indicated that pH, TDS, conductivity, salinity, transparency, depth and hardness showed significant difference (p < 0.05) among the three wetlands. Thirty-six fish species were recorded from the three wetlands out of which 2 species were vulnerable (VU) and 1 species was near threatened (NT). Species richness declined in all the studied wetlands ranging from 22.85 to 54% from the year 2002. The Canonical Correspondence Analysis showed a varying relationship of climatic and environmental parameters with the occurrence of fishes indicating species-specific adaptive capacity. The study also revealed a decrease in fish production (1991 to 2017) with the decreasing trend in rainfall and the increasing trend in temperature showing enviro-climatological influence. The new information generated would help to manage the wetland resources for sustainable fisheries enhancement and biodiversity conservation.