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The toxicity of aqueous and ethanolic extracts of Parkia biglobosa pods (95, 85, 75, 65 and 55 mg/l) on Clarias gariepinus was investigated under laboratory condition over a 96 h exposure period. Fish exposed to both extracts exhibited clinical signs including eventual death but was not observed in the control fish. Weight change in fish was observed as well as the effect of the plant on the water parameters. However, clinical signs and death were more in fish exposed to the ethanolic extract. It was concluded that aqueous and ethanol extracts of P. biglobosa pods are toxic to C. geriepinus juveniles with the ethanol extract being more toxic, which shows that apart from the bark of P. biglobosa, the pods has piscicidal property and can be put into use in the control and management of fish ponds to eradicate predators by farmers.

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Quantitative and qualitative analysis of bacterial isolates in water and fish samples (Oreochromis niloticus and Clarias gariepinus) from Jebba Lake were carried out using primary isolation media and microbact identification kits. The concentration of heavy metals, Lead (Pb), Copper (Cu), Cadmium (Cd), Chromium (Cr) and Arsenic (As) were determined using Atomic Absorption Spectrophotometer (AAS). Samples were collected from five (5) different stations. Station Jl.1 and Jl.2 are located at the upper course of the lake and were characterized by high human activities (washing, bathing, mining and animal husbandry operations) especially in sample station Jl.2. Sample station Jl.3 has low human activities, however it has a tributary with high mining activities. Station Jl.4 has high domestic washings but low animal husbandry operation and low mining activities. Station Jl.5 has low domestic washings, low animal husbandry operation and low mining activities. Mean faecal coliform count of sample station Jl.1 (580.83 CFU/100ml) and station Jl.2 (700.83 CFU/100ml) were above maximum permissible limit for Federal Environmental Protection Agency (FEPA). Faecal coliform count of sample stations Jl.3, Jl.4 and Jl.5 were below maximum permissible limit. Maximum faecal coliform count during the wet season was 1600.00 CFU/100ml, while the maximum count during the dry season was 920.00 CFU/100ml. Bacterial species such as Aeromonas caviae, Aeromonas hydrophila, Pseudomonas fluorescens – 25, Escherichia coli, Moraxella species, Mannheimia (pasturella) haemolytica, Pseudomonas aeruginosa, Pseudomonas fluorescens – 35, Escherichia hermannii were found in water samples and species such as Vibrio alginolyticus, Moraxella species, Escherichia hermannii, Vibrio parahaemolyticus, Aeromonas hydrophila were isolated from fish intestines and gills. Concentration of Cu, Cr and As in water was observed to be within permissible limit but the concentration of Pb and Cd were above tolerable limit. In fish organs, the concentration of heavy metals were within permissible limit except that of Pb and As in Oreochromis niloticus fish intestines (ONFI) (0.38±0.00 and 0.03±0.00 respectively) and Clarias gariepinus fish intestines (CGFI) (0.40±0.00 and 0.03±0.01 respectively) which were above maximum permissible limit by standard organizations. Key words: Jebba Lake, water, fish, Oreochromis niloticus, Clarias gariepinus, bacteria, heavy metals

The toxicity of aqueous and ethanol extracts of Parkia biglobosa pods (95mg/l, 85mg/l, 75mg/l, 65mg/l and 55mg/l) on Clarias gariepinus was investigated under laboratory condition over a 96h exposure period. The effect of aqueous and ethanolic extracts of Parkia biglobosa pod on the histopathology of liver of the fresh water Cat fish (Clarias gariepinus) was investigated. The differential acute toxicity of aqueous and ethanolic extracts of Parkia biglobosa pod on Clarias gariepinus were carried out under laboratory conditions. The LC50 after 96 h of exposure for aqueous and ethanolic extracts of Parkia biglobosa were 2.95 and 2.23 g/L, respectively. These values showed that ethanolic extract of Parkia biglobosa pod was more toxic than its aqueous extract. Signs of agitated behaviours, respiratory distress and abnormal nervous behaviours including eventual deaths were observed in exposed fish. Control fish neither died nor exhibited any unusual behaviour. Histopathological changes of liver was noticed when Clarias gariepinus was exposed to aqueous extract of Parkia biglobosa for 96 h. Liver from exposed fish showed congestion, perivascular cuffing, vacuolation, dilated sinusoidal spaces, necrosis, pyknosis and mononuclear cell infiltration. Fish from the control group showed no histopathological changes. However clinical signs and death were more in fish exposed to the ethanol extracts. This investigation revealed that extract from pod of Parkia biglobosa has piscicidal property and can be put into use in the control and management of fish ponds by farmers. Therefore, this plant can actually be use as a biological control in eradicating predators and unwanted organisms in the ponds by farmer instead of using agrochemicals.