Assesment of ecological quality of man-made Koko lake (Korhogo, Côte d’Ivoire) using biotics indices based on aquatic insects.

Abstract

Abstract Assessment and monitoring of surface water quality using biological methods has been popularized in recent years. It is within this framework that the present study attempts to use biological indices to determine the quality of Koko Lake in order to propose solutions for obtaining acceptable water for human consumption. Aquatic insects were sampled in four habitats, using a hand net and a van Veen grab, from March to August 2018. The study reported 10 families and 5 orders of aquatic insects collected. Diptera and Heteroptera were the most diverse and abundant order, respectively. The family Notonectidae was found to be abundant, however Chironomidae was the most diverse family. The ASPT score suggests very good lake quality, however the BMWP index indicates moderate water quality for sites S1, S2 and S4 and good quality for site S3. The FBI score indicates average water quality for some sites and fairly poor water quality for others. Since the water in Lake Koko is reserved for consumption, monitoring measures must be taken by the Korhogo city authorities.