Md kamrul Hasan

The present study revealed that a total of 101 indigenous species of large fish (28 species) and Small Indigenous fish (73 species) belonging to 63 genera and 31 families were observed and identified while 17 exotic fish species were found under 5 families. Among the indigenous species, the highest number of species were found in family Cyprinidae and Bagridae with a relative diversity of 28.28% and 11.11%. In case of group species richness, highest number 27 fish species were found in catfish group followed by 12 species of carp, 8 species of each barbs and minnows, 6 species of eel fish, 8 species of loaches, 4 species of each prawn, snake-headed or airbreathing fish and glass perches, 3 species of each climbing perches and clupeid, 2 species of each goby fish, knifefish and puffer fish, and rest of the group true perch, leaf fish, halfbeak fish, Needlefish, mullet fish, anchovies and killifish has one species. Of the total species, 47 species were considered as least concerned, 10 species as vulnerable, 11 species as endangered, 11 species as critically endangered, 14 species as nearly threatened and 8 species as data deficient. Considering the seasonal variation for all selected areas simultaneously, Shannon-Weaver diversity (H) index were found ranged from 3.53 (May) to 4.37 (January) where the highest Shannon-Weaver diversity index value 4.37 were found in winter season while 3.01 in Phulkumar, 3.73 in Dudhkumar, 3.87 in Dharla, 3.67 in Tista and 3.79 in Brahmaputra were recorded separately.