ASSESSMENT OF WATER QUALITY PARAMETERS IN RELATION TO FISHERIES RESOURCES IN OSUN RIVER CATCHMENT, NIGERIA.

Résumé

Osun River Catchment (ORC) is fed by various tributaries with differential water composition and varying human activities therefore periodic assessment of its water quality parameters is essential for sustenance of fisheries resources in the catchment. Triplicate bi-monthly sampling was done from seven sampling points (A – G) randomly selected based on the information from soil type, drainage, land usage and geographical formation of ORC from November, 2017 to March, 2018.
Parameters measured were Temperature, Dissolved Oxygen (DO), Biological Oxygen Demand (BOD), Ammonia and pH. Apart from DO and BOD which had an inverse relationship, the mean water quality parameters measured from the entire ORC were within the range for sustenance of fisheries resources. The overall high mean BOD (24.1 ± 0.28 mg/l) indicated the presence of
pollution which resulted to slight decrease in DO (4.6 ± 0.31 mg/l) below the recommended levels. Significant differences (P<0.05) were observed across some months for Temperature, DO, BOD and pH except for Ammonia which showed no significant difference (P>0.05) within the months. Maintenance of our aquatic system is therefore essential for sustenance of fisheries resources.