Biodiversity Assessment Of River Singla In Karimganj District Of Assam: A Survy Of Fish Species Composition And Water Quality.

Abstract

The present investigation has been carried out to examine the water chemistry and ichthyofaunal diversity of River Singla in Karimganj district of Assam during the study period from 2018-2020. The water chemistry parameters include Air Temperature (AT), Water Temperature (WT), Turbidity, pH, Dissolved Oxygen (DO), free Carbon-di-Oxide (FCO₂), Total Alkalinity (TA), Total Hardness (TH), Conductivity (Cndvty), Nitrate (NO₃), Phosphate (PO₄) etc. and were estimated by following standard procedure of American Public Health Associatio (APHA). During the investigation period, the ichthyo species were collected by using different experimental fishing gears such as gill nets, cast nets, drag nets, triangular scoop nets and a variety of traps etc. The fishes were preserved in formaldehyde solution and were then identified by following standard literature and keys. During the study period the averages of the parameters in three different seasons such as AT and WT were found to be within a range from 22±1.180C to 33.6±0.50⁰C and 18±0.70⁰C to 25.4±0.50 ⁰C resp; pH and TA fluctuated between 6.68±0.10 to 7.98±0.11 and 34±1.58 mg/L to 58.4±0.92 mg/L resp.; the value of DO and FCO₂ portrayed a range of 7.12±0.13 mg/L to 8.24±0.19 mg/L and 1.68±0.12 mg/L to 3.16±0.13 mg/L; the TH and conductivity ranges from 40.4±0.6 mg/L to 65.4±0.81 mg/L and 99.4±0.92 μmohs/cm to 187.4±1.98 μmohs/cm respectively. In addition, the value of nitrate and phosphate has been recorded as 0.096±0.00 mg/L to 0.354±0.01 mg/L and 0.29±0.01 mg/L to 0.516±0.02 mg/L respectively. The ichthyofaunal diversity revealed a total of 58 species of fishes belonging to 42 genera, 20 families and 8 orders have been recorded from River Singla during the study period. Orderwise cypriniformes (43%) reflected highest abundance, while Clupeiformes and beloniformes reflected least abundance (2% each).