Abstract

Sublethal effect of the dispersants Goldcrew and Corexit on selected blood parameters (White blood cell count- WBCC; Red blood cell count- RBCC; Platelet; Haemoglobin-Hb; and Packed Cell Volume - PCV) in Clarias gariepinus (Burchell) were studied. This was done in other to gauge the usefulness of blood parameters as good indicators of pollution and simulate the possible effect of clean-up operations on fish. Fish were exposed for four consecutive weeks in a static renewal condition and blood parameters measured weekly for the entire period at different levels of inclusion of dispersants. Results from the investigation revealed that dispersant effect on all blood parameters were not significantly different for the two dispersants (P > 0.05). Concentration of dispersants had a marked significance on blood parameters (P < 0.05); RBCC, PCV, Hb, platelet counts all decreased with increased concentration, while WBCC increased with increase in dispersant concentration. Duration of exposure had a marked significance on all blood parameters (P < 0.05) except in WBCC which was not significant at all exposure times. This study inferred that the two dispersants (Goldcrew and Corexit) are equally deleterious to fish health as they impact negatively on fish blood on the same scale.

Key words: Clarias gariepinus, corexit, blood, goldcrew, sublethal.