Mayflies (Order Ephemeroptera) Distribution as Indicators of the Water Quality Status of a Stretch of Ovia River (Iguoriakhi), Edo State, Southern Nigeria

The distribution of Ephemeroptera (Mayflies) community in a stretch of Ovia River (Iguoriakhi), Edo State, Nigeria, was investigated at four designated stations over a period of 8-months.  Eight taxa belonging to four families; Baetidae (5), Adenophlebiidae (1), leptophlebiidae (1), and Siphlonuridae (1) were encountered in the study. The most dominant taxa were adenophlebiidae and baetidae contributing 22.2% and 77.78% in station 1, 24.07% and 75.93% in station 2, 50.96% and 49.04% in station 3 and 36.97% and 63.03% in station 4. Aposteriori test for multiple comparison showed that the density of ephemeroptera at station 4 was significantly higher (P<0.01) than those at stations 1, 2, and 3, which were not significantly different from each other. The diversity indices showed that taxa richness, Shannon diversity and evenness were moderately impacted at station 2. The aquatic macrophyte -rich stations 1, 3 and 4 were non-impacted compared to station 2. This study showed that mayflies (Ephemeropterans) are good indicators for freshwater quality monitoring.