Fish diversity and habitat ecology of Dihing river - A tributary of Brahmaputra river

Abstract

Extensive survey of fish diversity of the Dihing River (a tributary of Brahmaputra River) was conducted from February’ 2013 to January’ 2014. Seasonally sampling was carried out at three sites. During the survey, a total of 50 fish species belonging to 18 families and 34 genera have been recorded from this river and it was found to be dominated with Cyprinidae family followed by Bagridae and Siluridae. Habitat ecology reveals that the minimum (18.5 °C) water temperature was recorded in winter and the maximum (25.76 °C) in monsoon; lowest (20.73 °C) air temperature in winter and highest (26.66 °C) in monsoon; highest (141.33 µS cm-1) conductivity in winter and its lowest (89 µS cm-1) in monsoon; minimum (13.56 cm) transparency in monsoon and its maximum (72.16 cm) in winter; minimum ( 0.40 m/s) current flow in winter and the maximum (0.98 m/s) in monsoon; the lowest (7.16) pH in monsoon and highest (7.76) in winter; the lowest (6.33 mg/l) DO in post monsoon and its highest (7.51 mg/l) in pre monsoon; minimum (6.13mg/l) FCO2 in pre-monsoon and its maximum (7.97 mg/l) in post monsoon; the lowest (32.44 mg/l) alkalinity in monsoon and its highest (42.89 mg/l) in winter; the highest (82.23 mg/l) hardness in pre-monsoon while its lowest (36.36 mg/l) in post monsoon; minimum (161.66mg/l) TSS in winter and maximum (393.33 mg/l) in smonsoon; the minimum (108.33 mg/l) and maximum (296.66) TDS was found in winter and monsoon season respectively.