Waste dry cell batteries are frequently improperly disposed and subsequently washed into water bodies-- causing deleterious effects on fish particularly Clarias gariepinus which inhabits diverse freshwater habitats. Acute toxicity of water-soluble fractions of waste dry cell batteries was investigated on C. gariepinus fingerlings under laboratory conditions in 96 hours. Ten (10) C. gariepinus fingerlings were exposed to acute concentrations (0.31, 0.63, 1.25, 2.50, and 5.00 g/L) of waste dry cell batteries and a control (0.00 g/L), each duplicate replicated. Histopathological alterations  evident in the gills were lamellar fusion, hyperplasia, inter-lamella space occlusion, hypertrophy and erosion of secondary lamellae. The liver showed nuclear and hepatocytes degeneration, vacuolation and portal congestion. Acute concentrations of water-soluble fractions of waste dry cell batteries caused significant (P<0.05) changes in the histomorphology of the gills and liver of C. gariepinus fingerlings, therefore indiscriminate disposal of waste dry cell batteries around riparian ecosystem should be safeguarded to reduce the declining diversity and abundance of freshwater fish species. Keywords: African catfish, 96 hr.LC50, Fingerlings, Histopathology Zinc-carbon battery

Background: Histopathological changes have been widely used as biomarkers in determining the effects of pollutants on fish. Leaves of Balanites aegyptiaca, a deep-rooted, evergreen or semi-deciduous, multi-branched, spiny tree have been reported to have pesticidal, anaesthetic and ichthyotoxic effects. This study sought to find out the effect of sub-lethal concentrations (5.00, 11.00, 21.00, 43.00, and 86.00 mg/L) of B. aegyptiaca on histopathology of gills, kidney, and liver of mixed-sex Oreochromis niloticus fingerlings Methods: A total of 120 O. niloticus fingerlings (mean weight 23±0.03 g and mean total length 12.50±0.39 cm) were exposed to aqueous crude leaves extract of B. aegyptiaca. The gills, kidney, and liver were excised and processed routinely for the elucidation of histopathological changes Results: Dose-dependent histopathological changes were observed in the three organs (gills, kidney and liver) of O. niloticus exposed to graded concentrations of B. aegyptiaca. Gills showed moderate to severe secondary lamellae fusion, desquamation, and primary lamellae congestion while the kidney displayed mild to severe renal tubular epithelial cell degeneration and necrosis as well as pigmentation of renal tissues. The liver showed varying degrees of histo-architectural alterations such as hepatocellular degeneration and necrosis, cellular infiltrations, kupffer cell proliferation, portal, and sinusoidal congestions Conclusion: Owing to these histological alterations in the gills, kidney, and liver observed in this study, prolonged exposure of fish to B. aegyptiaca should be discouraged to preserve fish diversity

Chemicals have been used to anaesthetize fish but due to their hazardous effects on the environment, fish and humans environmentally friendly plant anaesthetics are being sought. Fruit of Desert date (Balanites aegyptiaca) is nontoxic to humans but has been reported to have anaesthetic potentials on fish. This study investigates anaesthetic effect of aqueous crude fruit extract of B. aegyptiaca on African catfish (Clarias gariepinus) fingerlings. Phytochemical and proximate compositions of the fruit were screened. Exactly 120 C. gariepinus fingerlings (mean weight 32.13±2.43g and mean total length 23.88±2.11cm) were used for the experiment. A total of 10 fingerlings were exposed to each of 2.00, 2.50, 3.00, 3.50 and 4.00g/L concentrations of aqueous crude fruit extract of B. aegyptiaca and a control in 6 plastic tanks (45x28x25cm) filled with 10L of tap water. Setup was arranged in randomized block design and replicated. Temperature, dissolved oxygen, pH, free carbon dioxide and total alkalinity were monitored. Results revealed long mean induction (25.05±3.35 min) and recovery (108.35±2.45 min) times with resultant mortalities (40%) of C. gariepinus fingerlings. significant correlation (P<0.01) exists between concentration of the fruit extract and induction time as well as between fruit extract concentrations and survival of fingerlings. Aqueous crude fruit extract of B. aegyptiaca is, therefore, not effective for anaesthetization of C. gariepinus fingerlings hence should be avoided. Keywords: Anaesthetic, Balanites aegyptiaca, Clarias gariepinus