The effects of petroleum refinery and fertilizer plant effluents on some haematological parameters (packed cell volume - PCV, Total Leucocyte Counts - TLC and Differential Leucocyte Counts) in two species of cichlids; Sarotherodon melanotheron and Tilapia guiniensis were studied. This was with a view to assessing the usefulness of these parameters as indicators of pollution in Niger Delta Estuaries. Average Packed Cell Volume (PCV) ranged from 24.4 + 3 to 24.4 + 4.4 cm3 in T. guiniensis while the values for S. melanotheron ranged form 24.3 + 3 to 26.5 + 4.7 cm3. PCV is probably not a good indicator for contaminants in both species. There were high significant differences (p<0.0001) in Total Leucocyte Counts of the two species from the various sites. The highest values for both T. guiniensis (18427 + 3896 cells/l) and S. melanotheron (17776 + 3656 cells/l) were found in samples from creeks receiving fertilizer plant effluents, while values for samples from the control creek were the lowest giving 9042 + 2859 cells/l for T. guiniensis and 8662 + 2985 for S. melanotheron.
(Global Journal of Pure and Applied Sciences: 2002 8(3): 305-310)