Certain geomorphological features and fish fauna of river Mara Bharali in Sonitpur district of Assam

Rapid industrialization, water abstraction and the extensive use of pesticides in agriculture have severe strains on rivers and resulted in deterioration of water quality. The present investigation on certain geomorphological aspects and fish fauna was conducted in the remnants of old channel of river Jia Bharali called as Mara Bharali at Tezpur in the Sonitpur district of Assam from December, 2017 to November, 2019.

Five sampling stations were selected that covers a stretch of 16.5 km. River width, river depth, bank type and riparian vegetation were assessed following Armantrout (1999) and statistical analysis were conducted. Fish species were collected and identified following Talwar and Jhingran (1991).

Maximum value of river-width was found at site MB5 (12.821±6.067 m). Mean water current velocity was found to be maximum at site MB5 (0.645±0.056 ms⁻¹) followed by MB1 (0.433±0.045 ms⁻¹). The river depicts riffle-pool morphology and consisted of substrates in the form of pebbles, sand and silt. Thirty four fish species belonging to 25 genera, 08 orders and 17 families has been recorded. Moreover, random sampling analysis shows the presence of 14 rare species in Mara Bharali.