Abstract

Ichthyofauna plays a vital role as consumers in the food chain and maintain the nutrient balance. The diversity and abundance of ichthyofauna depends on the nutrient levels in the aquatic ecosystem. The current study investigates ichthyofauna diversity and water quality across the lakes in Bangalore, Karnataka State, India. The order Cypriniformesis dominant in Bangalore lakes and 18 species were recorded in the current study, which is lower compared to the earlier report of 55 species in 1970. The decline in the native species and dominance of the exotic invasive species is mainly due to higher nutrient levels with the sustained inflow of untreated or partially treated wastewater to lakes. Lakes were earlier connected and now the loss of interconnectivity has also led to the disappearance of native species. Lakes of Bangalore are facing severe threat of pollution apart from the problems of encroachment of

lakes, habitat loss, invasion of exotic species and over-harvesting of wetland resources. The quality of water was monitored and the overall quality is assessed through Water quality index (WQI). Principal component analysis was performed to understand the contribution of different physico-chemical parameters and their influence on ichthyofauna species diversity. The variations in the physico-chemical parameters have altered habitat conditions, affecting the diversity and abundance of ichthyofauna biodiversity. The study highlights the need to formulate strategies to sustain native species of ichthyofauna, which support the livelihood of local people through effective regulatory measures for preventing pollutants entering the water body.

Keywords: Ichthyofauna, Lakes, Water pollution, Diversity, WQI.