Aquatic biodiversity in upland streams of Kameng drainage in Arunachal Pradesh

Abstract

The study was conducted to analyze the physicochemical parameters, nutrient variables, plankton and fish diversity in three snow-fed tributaries rivers viz., Dirang chu, Sangti and Tenga of Kameng drainage in West Kameng district of Arunachal Pradesh in the Eastern Himalayas during 2016–17. The key physicochemical parameters in the three rivers viz., temperature, pH, dissolved oxygen were found in the range of 11.42±0.04 to 14.25±0.06°C; 7.32±0.02 to 7.9±0.03; 8.06±0.05 to 8.31±0.05 ppm, respectively. Nutrient variables i.e., ammonium, nitrite, phosphate, alkalinity, hardness were observed in the range of ˂0.01 mg/l; 8.33±0.58 to 11.0±1.0 μg/l; 0.11±0.005 to 0.38±0.03 mg/l; 25.33±2.31 to 17.33±2.31 mg/l; 26.66±1.15 to 15.33±1.15 mg/l, respectively. The rivers being snow fed remained clear and transparent (0.39±0.02 NTU) during the study period. The abundance of plankton species was comprised of Stigeoclonium (50%), Pinnularia (20%), Navicula (15%) at river Dirang chu, whereas Stigeoclonium (30%), Fragilaria (30%) and Lyngbya (10%) dominated at river Sangti, followed by Pinnularia (40%), Acanthidium (20%) and Synedra (10%) at river Tenga. Three species of snow trout (Schizothoracids) remained abundant and formed the major catch with an average length of 24.16 ± 6.17 cm and average weight of 161.2 ± 102.22 g in cast nets and noose and line method. The abundance of diverse plankton groups along with a favorable range of most of the essential hydrological characteristics indicated a good health of the water body and an environment conducive for thriving of snow trout and endowing nutritional security in turn for the mountain dwellers in a remote and fragile Himalayan region of India.