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This study examined the effectiveness of Moringa oleifera fresh root-bark extract as an organic piscicide to control predatory fish in ponds. Acute-lethal toxicity (LC 50 ) of Moringa oleifera extract for 96-h exposure for Oreochromis niloticus fingerlings was determined at 26.45 mg l -1 . The extract was more toxic at higher concentrations of 100 mg l -1 , with fingerlings showing abnormal swimming, restlessness and uncoordinated behaviour before death. Moringa oleifera extract could be used as an organic piscicide in aquaculture pond management. Baseline information on its toxicity to fish could serve as a tool in fisheries management to wipe out predatory fish in ponds prior to stocking.

ABSTRACT:The influence of water soluble fraction of crude oil from Afiesere oil field on water quality components and its consequent effect on haematological and biochemical parameters in juveniles of Oreochromis niloticus were evaluated. After a preliminary determination of the 96 h-LC50 of crude oil by probit regression was found to be 92.38 mg/l, fish were exposed to 4 sub-lethal concentrations (30, 45, 60 and 75% of the LC50 corresponding to 28, 41, 55 and 69 mg/l respectively) of the oil and a control. After 84 days of exposure, blood was collected and used in conducting haematological and biochemical analyses. Exposure of water to crude oil caused increased levels in chloride, conductivity, salinity, magnesium, biochemical oxygen demand, chemical oxygen demand, turbidity and Nitrate. The crude oil contaminated water resulted in a significant reduction (p<0.05) in the values of red blood cells, packed cell volume and haemoglobin. Although no definite trend in the values of computed haematological indices was observed, MCHC, however, decreased with increased concentration. Also, Glucose, ALP, ALT, AST, Urea and creatinine activities of all the affected set of fish, which have been exposed to the crude oil were significantly higher (p<0.05) in comparison to their respective control. © JASEM https://dx.doi.org/10.4314/jasem.v21i6.7

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