Abstract

Objective: To assess water quality and diversity of aquatic insects relative to effluents discharge from resort centres in Ethiope River. Methods: Water samples collected from three study stations were analyzed using APHA methods while the kick sampling techniques were used for collection of aquatic insects. The obtained data were subjected to statistical analysis at significance level of 0.05. Results: Among the study stations, water temperature varied from 20 °C to 34 °C with a mean temperature of (26.17 ± 2.37) °C, while pH was recorded from 5.57 ± 0.18 to 5.94 ± 0.21. Statistically, water temperature, pH, dissolved oxygen and conductivity were significantly different (P < 0.05) among months. A total of 14 taxa comprising 300 individuals belonging to orders of Odonata, Coleoptera, Hemiptera, Plecoptera, Ephemeroptera and Diptera were recorded. There was significant difference in the overall insect diversity among the stations. Ephemeroptera was the largest and the most dominant order having 55.33% species, followed by the Odonata (15.33%), Coleoptera (9.67%) and Diptera (9.67%), Hemiptera (7%) and Plecoptera (3%). Shannon–Wiener and Evenness index were not significant (P > 0.05) in the stations. Conclusions: Significant relationships were recorded between water quality parameters and occurrence of Neoperla spio, Caenis horaria, Baetis and Chironomus species. The observed changes in aquatic insect composition were principally due to alteration in water quality. The weak correlation between aquatic insects and water quality can be attributed to functional adaptations to environmental changes. Aquatic insects have been proved to be good bioindicator of pollution and long-term monitoring of the aquatic insects is necessary for water quality evaluation in Ethiope River.

Authors and Affiliations