Biodiversity and its conservation are regarded as one of the major issues of enabling sustainable use of natural resources. It is necessary to protect biodiversity in all ecosystems. Diversity reduces pest and disease problems and encourages recovery from disturbances due to natural or man made activities. This paper focusses on the diversity of fish population and their conservation in a freshwater tectonic Lake Sone (3458 ha) in Assam, India. Our study reveals 70 fish species in the Lake, which belong to 49 genera under 24 families. Of these, 84.2% belong to the primary freshwater group (Cyprinids 35.39%) while the rest to the peripheral class. Higher fish diversity was observed during monsoon season. Attempts have been made to portray fish diversity of Sone zoogeographically and emphasize the value of conserving biodiversity for the maintenance of diverse, resilient functioning of ecological life-support systems.

Limnological parameters are of prime importance in fish production in a lake eco system. Results of linear regression revealed significant correlations between fish yield (FY) and soil organic carbon (SOC) and aquatic macrophyte biomass (AMB). Analysis also revealed significant relation of FY with water pH, total alkalinity, conductivity, SOC, soil potassium and AMB.

Key words: Fish diversity, Conservation, Aquatic Ecosystem, Lake Sone.