Appraisal of Fish Health Assessment Index in Three Major Reservoirs in Ekiti State, Southwest Nigeria

Increased anthropogenic activities and chemical contaminants in Ekiti State reservoirs have substantial effects on the reservoirs’ fish, which are valuable indicators of the health of the aquatic environments. The aim of the study was comparatively assessing the probable environmental deterioration in Egbe, Ero and Ureje reservoirs using the fish Health Assessment Index (HAI). Blood component analysis, necropsy data, and parasite index were used to compute HAI. Haematocrit values were not within the normal range in 78.85% (Ureje reservoir), 73.47% (Egbe reservoir), 57.38% (Ero reservoir), and endoparasite were present in 32.69%, 26.53% and 44.26% of fish examined from Ureje, Egbe, Ero reservoirs. Abnormalities of eyes, fins, skin, and liver were observed in a small proportion in the fish from the reservoirs. HAI of Oreochromis niloticus in the reservoirs was in order of Ureje reservoir (31.15 ± 2.81) > Egbe reservoir (29.39 ± 2.57) > Ero reservoir (25.00 ± 2.43). Condition factor of fish was in order of Ero (2.07 ± 0.03) > Egbe (1.98 ± 0.01) > Ureje (1.97 ± 0.01). In comparison to control site, reservoirs’ fish were in deplorable conditions as evidenced by HAI. Therefore, HAI is useful as an early indicator of the well-being of the aquatic ecosystems, in order to enhance the sustainability of the aquatic resources and also to compare the health status of fish from different aquatic environments.