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

A biomonitoring study of River Jatinga located in south Assam, north east In-dia was conducted for the first time. The study aimed to evaluate water quality of the river in different stretches using aquatic in-sect as bioindicators. Insect samples were collected from selected sites of mid-stream 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 win-ter. Hemiptera, the most di-verse group was represented by six families with highest relative abundance. The study found that although both the sites were repre-sented by same functional feeding groups, there were seasonal and spatial varia-tions in the families of in-sects and their percentage occurrences. All the biotic indices, BMWPTHAI, SIG-NAL2 scores, EPT % and HFBI have shown relatively better quality of water of the River Jatinga in the mid-stream than that in the downstream during mon-soon and post monsoon sea-sons. Presence/absence and abundance of certain insect groups can provide infor-mation about health of the river.