Toxic effect of Raphia vinifera on fish leech (Piscicola geometra)

This study examines acute toxicity of Raphia vinifera on fish leech, Piscicola geometra. The leeches with a mean total length of (TL) 4.2+1.0cm were exposed to various concentrations of both crude powdered and ethanolic extracts of the botanical. Median lethal concentration (LC50) was determined with static-renewal tests using logarithmic and arithmetic graphic methods. The LC50 (for 96 hours of crude powdered (aqueous) extracts of the botanical on Piscicola geometra was 1.10 ppm arithmetically and 1.14ppm logarithmically. The 95% confidence limits was 0.10ppm arithmetically and 0.12ppm logarithmically. The LC50 of ethanolic extract of the poison at 96-h was 0.5ppm arithmetically and 0.48ppm logarithmically. The 95% confidence limits were less than 0.10ppm. The use of extracts of R. vinifera in the control of leeches in fish ponds is discusse

The relationship between some physicochemical parameters and plankton composition on fish production in ponds

The effect of physico-chemical parameters and plankton composition on fish production in ponds was investigated in six fish farms for eight weeks. The physicochemical parameters investigated were temperature=25-30 plus or minus C, transparency=0.45-0.57m, dissolved oxygen=3.0-10.9mg/l, pH=6.0-7.7, dissolved carbon dioxide=5.46-28.3mg/l, total alkalinity=44.37-80.0ppm, chemical oxygen demand=31.88-72.18mg/l and biological oxygen demand=0.66-48.34mg/l. Plankton composition varies and was made of four families of phytoplankton namely; Cyanophyceae, Chlorophyceae, Dinophyceae and Diatomida; and four families of zooplankton viz; Protozoa, Rotifera, Copepoda and Dinoflagellates. Farm 1 and 6 recorded the highest average weight of about 1.0kg and average total length of about 40.0cm for the two fish species. This study showed that fish yield was dependable on the quality and management of pond water characteristic

Lethal Limits and Respiration in the Cichlid Fishes, Tilapia zillii , Sarotherodon galilaeus , S. melanotheron and Oreochromis niloticus Exposed to Effluent from Chemistry Department Laboratories.

In this study, the lower and upper lethal limits, LC50 and respiration of the freshwater cichlid fishes, Tilapia zillii, Sarotherodon galilaeus, S. melanotheron and Oreochromis niloticus exposed to effluents from Chemistry Department Laboratories were investigated. The mixing of the effluents produced a reduction in pH and dissolved oxygen and a fairly constant temperature and salinity of the media, while the toxicity of the effluents increased. The LC50 values after 24 and 48-h exposure in the effluent media were 0.24% and 0.21% for T. zillii; 0.26% and 0.24% for O. niloticus; 0.25% and 0.23% for S. galilaeus; 0.27% and 0.26% for S. melanotheron, respectively. The effect of chemical effluent on the rate of respiration of the treated cichlids produced lower rates of oxygen consumption in the order of S. galilaeus>O. niloticus>S. melanotheron>T. zilili in the highest concentration of the effluent. The results obtained from this study have shown that the effluents from Chemistry Department Laboratories are not treated as they produced respiratory impairment and physiological dysfunction in the exposed fish. It is suggested that proper treatment of these effluents be carried out before being discharged into the surrounding stream

Lethal Limits and Respiration in the Cichlid Fishes, Tilapia zillii , Sarotherodon galilaeus , S. melanotheron and Oreochromis niloticus Exposed to Effluent from Chemistry Department Laboratories.

In this study, the lower and upper lethal limits, LC50 and respiration of the freshwater cichlid fishes, Tilapia zillii, Sarotherodon galilaeus, S. melanotheron and Oreochromis niloticus exposed to effluents from Chemistry Department Laboratories were investigated. The mixing of the effluents produced a reduction in pH and dissolved oxygen and a fairly constant temperature and salinity of the media, while the toxicity of the effluents increased. The LC50 values after 24 and 48-h exposure in the effluent media were 0.24% and 0.21% for T. zillii; 0.26% and 0.24% for O. niloticus; 0.25% and 0.23% for S. galilaeus; 0.27% and 0.26% for S. melanotheron, respectively. The effect of chemical effluent on the rate of respiration of the treated cichlids produced lower rates of oxygen consumption in the order of S. galilaeus>O. niloticus>S. melanotheron>T. zilili in the highest concentration of the effluent. The results obtained from this study have shown that the effluents from Chemistry Department Laboratories are not treated as they produced respiratory impairment and physiological dysfunction in the exposed fish. It is suggested that proper treatment of these effluents be carried out before being discharged into the surrounding stream

Haematological and histopathological examinations of African mud catfish (Clarias gariepinus) exposed to petroleum wastewater

Effects of petroleum refinery wastewater on Clarias gariepinus juvenile were investigated. Commercially obtained C. gariepinus fingerlings were acclimatized in a plastic tank (100 L capacity) of de-chlorinated tap water at 25±2°C for 14 days and fed with commercial feed pellet at 2% body weight of the fingerlings. Bioassay tests were carried out in four transparent plastics tank with nominal concentrations of 100 ml, 200 ml, 300 ml of the wastewater added to 40L of de-chlorinated tap water and only de-chlorinated tap water as control. Each tank contains twenty fish samples, while the assay was replicated three times concurrently. Following standard procedures, behavioural response, growth changes, haematological and histopathological tests were carried out on the samples. Significant reduction in the weight was observed in the fingerlings cultured with the wastewaters, while no significant difference occurred in the control fish. Highest values of Packed Cell Volume (PCV) (22), Haemoglobin (HB) (7.0), Red Blood Cell (RBC) (1.62) and endocochlear potential (EP) (5) were recorded for the control fish than exposed fish. On the other hand, Haptoglobin (HP), Mean Corpuscular Volume (MCV) and Mean Corpuscular Haemoglobin (MCH) were higher in the blood of exposed fish than in control. Histopathologically, exposed fishes showed no visible lesion in gills except from the thickening of the lamellae as the concentration of wastewater increases, indicating an increase in tissue disintegration. Similarly, gross tissue disintegration was observed in those fish exposed to 200ml wastewater as evidenced by the presence of large open spaces (hepatocytes) in the liver

Characterization of tropical freshwater; River Ogun, Lagos Nigeria

Physico-chemical parameters and microbial contents of Ogun River at Magodo area, Lagos were investigated in relation to its safety for consumption. Water samples were weekly collected between August and December, 2016 at three equi-distance intervals for analysis on physico-chemical parameters, total bacterial count and biochemical tests following standard recommended procedures. Mean concentrations of the physico-chemical parameters were found in ranges for pH (6.68 ± 0.15 - 6.86 ± 0.21), temperature (26.78 ± 0.14 – 26.92 ± 0.31), electrical conductivity (355.40 ± 101.93 – 456.40 ± 115.77), total dissolved solids (166.80 ± 48.08 - 215.00 ± 54.29), dissolved oxygen (7.06 ± 0.01 - 7.08 ± 0.02), biochemical oxygen demand (25.59 ± 0.03 - 25.64 ± 0.01), chemical oxygen demand (98.75 ± 0.03 - 98.84 ± 0.02), total hardness (345.80 ± 1.28 - 349.40 ± 3.87), total alkalinity (9.28 ± 0.02 - 9.33 ± 0.02), nitrate (0.27 ± 0.00 - 0.28 ± 0.00), sulphate (0.55 ± 0.05 - 0.62 ± 0.00) and chloride (68.84 ± 0.77 - 74.97 ± 1.23). Total colony forming unit (Cfu) of bacteria in the river was found highest in descending order Centrimide Agar (CA) > Mac-Conkey Agar (MCA) > Plate Count Agar (PCA) > Mannitol Salt Agar (MSA) at the first and second serial dilution respectively. Biochemical tests showed the presence of Staphylococcus species, Escherichia coli, Pseudomonas aeruginosa, Proteus sp., Salmonella sp. and Baccillus sp. in the river. Variations in the microbial load and physico-chemical parameters in Ogun River as a result of different human activities around the river was found within the standard limits which makes the River safe for human consumption. Key words: River Ogun, microbial load, bacterial count, biochemical tests Trop

Heavy metals in shell fishes of Ojo River, Lagos State, Nigeria

The research examined the accumulations of six heavy metals including chromium (Cr), lead (Pb), iron (Fe), zinc (Zn), cadmium (Cd), and copper (Cu) in water as well as in three male and female species of crab (Cardisoma armatum, Callinectes danae, Callinectes ornatus) sampled from Ojo River in Lagos State of Nigeria. Physico-chemical parameters of the water samples from the River and heavy metal concentrations in the crab species obtained also from the River were examined using standard methods. The results showed that total dissolved solute (TDS), electrical conductivity (EC), salinity, dissolved oxygen, biological oxygen demand and chemical oxygen demand varied significantly along the River course, with TDS and EC being relatively high. Heavy metals detected in the crabs were Fe, Cu and Zn, with Cu being the highest in the species examined. The species C. ornatus presented the highest content of Cu followed by C. armatum and C. danae. The content of heavy metals (mg kg–1) among the crab species showed that Cu (23.47±0.10) > Zn (19.06±0.01) > Fe (16.85±0.01) in all the species except in C. armatum where Fe (1.26±0.44) was > Zn (1.19±0.02). Furthermore, Pb, Cd and Cr were not found in the crabs and this could be associated with the fact that the area consists mainly of residential houses, farms and a few industries. Notably, the content of the heavy metals was larger in the female than the male crabs. This study reported different levels of heavy metal accumulation in male and female species of crabs. Also, the shell fishes from Ojo River might be considered safe for consumption, but the need for continuous monitoring to prevent bioaccumulation is recommended