Monitoring of river health using aquatic insects: A study on Jatinga River, North East India

Abstract

A biomonitoring study of River Jatinga located in south Assam, north east India was conducted for the first time. The study aimed to evaluate water quality of the river in different stretches using aquatic insect as bioindicators. Insect samples were collected from selected sites of midstream and downstream of the river during monsoon-post monsoon, 2018 and winter-pre monsoon, 2019. A total of 25 families of aquatic insects recorded from 8 orders; Gerridae was eudominant in midstream across all the seasons with highest percentage in winter. Hemiptera, the most diverse group was represented by six families with highest relative abundance. The study found that although both the sites were represented by same functional feeding groups, there were seasonal and spatial variations in the families of insects and their percentage occurrences. All the biotic indices, BMWPTHAI, SIGNAL2 scores, EPT % and HFBI have shown relatively better quality of water of the River Jatinga in the midstream than that in the downstream during monsoon and post monsoon seasons. Presence/absence and abundance of certain insect groups can provide information about health of the river.