The water volume of lakes and rivers total around 126,000 km3, which is equivalent to 0.0093% of the total volume of liquid water in the world (WCMC, 1992). The province of Assam (in India) is gifted with myriads of riverine and tectonic Lakes (locally called "Beels") which alone constitute 81% (approx.) of the total lentic area ( > 1,20,000 ha) in Assam. In Assam, there are 1392 (approx.) Beels with a water spread area of 50,000 ha (approx.), of which, 50% of the Beel area has been derelicted. Nevertheless, contrary to average annual fish production of 6-7 kg per hectare from Indian reservoirs, the overall fish production from the beels of Assam is more than 100 Kg per hectare per year (Dey, 1981).

Seventy ichthyospecies belonging to 49 genera under 24 families have been recorded in lake Sone. Of these, 84.2% belong to the primary freshwater group, while the rest to the peripheral class. On the basis of Indian and Extra-Indian territorial distribution, the fish species of Sone include 20 widely distributed species and eight species of Northern India. Further, ecomorphologically, the true rheophilic group contains only one species while the semi-torrential group includes five species. The migratory class contains seven species and the plainwater group includes 57 fish species of the Lake.