No abstract

ABSTRACT:A study on the impact of effluent discharge on water quality and the benthic macro invertebrate fauna of the Awba stream and reservoir was carried out between April 2007 and May 2008. Benthic macro invertebrate and sediment samples were collected with a Van Veen grab, while physico-chemical parameters were sampled with Hach's Company Fish Farmers' Water Quality Test kit. Four stations were chosen for this study. A total of 4 taxa comprising 10 species of organisms were recorded. The abundance of these species and the physicochemical parameters at the various stations were significantly different (P<0-05). Dissolved oxygen was considerably lowest at Station 2 (1.38 ± 0.19mgl -1 ); a region of intense organic pollution during the study period. This was accompanied by high values of dissolved CO2 (20.0 ± 1.51mgl -1 ), total hardness (103.0±7.87mg (CaCO3)/l), ammonia-nitrogen (3.0±0mgl -1 ) and increased pH values (8.5±0.27). Water temperature values was also highest at this station (30.7±1.15˚C). The values obtained for the physico-chemical parameters and correlation values with the tested organisms indicated that changes in community structure had occurred as a result of changes in prevailing conditions in the habitat. The levels of trace metals (Zn, Mn, Cu, Pb, Ni, and Cr) were analyzed and there was no statistically significant difference in the values recorded between stations. The levels of these metals except zinc and manganese fell within the limits specified by USEPA as values recorded for zinc and manganese were higher than the acceptable limits specified by USEPA.

Biochemical compositions (total protein = TP, total lipid = TL, globulin = Gl, albumin = Al and albumin/globulin = A/G ratio) of Oreochromis niloticus liver, kidney and brain exposed to 0.5 ppm aqueous extracts of Raphia vinifera (AERV) were investigated. The various biochemical compositions fluctuated with time of exposure to AERV. TP ranged between 0.91-4.64 mg/dl, Al between 0.41 -3.02 mg/dl, Gl between 0.70-3.40 mg/dl, A/G between 0.20-3.50 mg/dl and TL between 571.3-998.2 mg/dl. Significant (P<0.05) decrease in TP, Gl and TL values of the liver over either the brain or the kidney at 21-day duration in AERV, indicated high energy requirement for detoxification function of the liver. With these biochemical compositions in O. niloticus, it is inferred that their uses in the fish varied according to production in the tissue and relative effect of AERV, which produced fish's physiological dysfunction.

Samples of traditionally smoke-dried Clarias gariepinus (Burchell), Chrysichthys nigrodigitatus (Lacepede), Sarotherodon galilaeus (Trewavas), Heterotis niloticus (Cuvier) and Heterobranchus bidorsalis (Geoffroy) were obtained from Oja Oba Market, Ago-Iwoye, Nigeria and examined for fungal infestation. The fish samples incubated on potato dextrose agar (PDA) for 7 days showed fungal infestation. Fungi isolated and identified included Mucor sp., Aspergillus sp., Rhizopus sp. and Fusarium sp. Six fungal species were isolated from C. nigrodigitatus, five each on C. gariepinus and H. niloticus.

No abstract