Radiographic studies on morphological anomalies in artificially spawned Heterobranchus longifilis Valenciennes, 1840 F1 generation

This study was designed to examine radiographically the morphological anomalies in artificially spawned 24-week-old Heterobranchus longifilis. A total of 22 morphological deformities observed from an F1 population of 4,871 were classified. Based on anatomical positions, most of the anomalies (49.99%) manifested in the bodies as stunted growth with a weight range of 240-358g, standard length (SL) of 18.7-29.1cm and stump body trait with a weight range of 445-810g, SL of 22.9-35.9cm. Anomalies of the vertebral column accounted for 27.27% with a weight range of 410-945g, SL of 27.4-36.8cm. Fin aberrations including agenesis were seen in 22.73% with a weight range of 548-840g, SL of 34.1-39.2cm. Radiographic examination revealed anomalies such as hypoplasia and hyperplasia of fins, supernumeracry and agenesis of fins, fin cleft, and fusion of fins, scoliosis and kyphosis. The phenotypic lateral body curvatures and stump body trait were basically due to varying degrees and positions of scoliosis and thus, pathological. The fin aberrations and agenesis were probably congenital. The anomalies affected feed accessibility; thus; impaired the growth of the fishes evidenced by the low body weights recorded in the deformed fish compared to the normal fish. In conclusion, the percentage of morphological aberrations observed in the F1 population is negligible (0.45%), thus it will not adversely affect production of H. longifilis via artificial induction.Keywords: Artificial induction, Heterobranchus longifilis, Morphological anomalies, Radiograph

Seasonal variations in physicochemical properties of water in some selected locations of the Lagos lagoon

The seasonal and spatial distributions of physicochemical parameters that determine water quality was studied in the Lagos Lagoon. Nine locations were selected according to the activities that take place in the areas. Parameters that determine water quality were measured during the months of February and July that represent dry and rainy season. Physical water quality parameters such as salinity, EC and TDS showed strong seasonal variation amongst stations and evaporation seem to be a major controlling force for these parameters in the lagoon. Generally, the data obtained suggests thatanthropogenic disturbances and the establishment of several types ofactivities with increased point and non-point storm water runoff shunted directly into Lagos Lagoon has negatively affected the water quality and made relationships between most of the parameters and the different locations complex

Effect of Stocking Density on Production of Clarias Gariepinus (Tuegels) in Floating Bamboo Cages at Kubanni Reservior, Zaria, Nigeria

The African Catfish (Clarias gariepinus, Teugels) were reared at three different stocking densities in bamboo-net cages to evaluate the effects of stocking density on growth, survival rate and food conversion ratio. Three hundred (300) fish with a total weight of 1.8Kg were stocked at 25, 50 and 75 fish/ m3 cage with a mean weight of 5.6±0.23g, 5.9±0.23g and 6.3±0.23 g/m3 respectively. The growth trial lasted for 150 days (May 2009 to October 2009). Twenty percent (20%) of the total biomass of the fish in each cage was weighed monthly and the bulk weights were calculated. Mortalities were recorded monthly. The final mean weights (±S.E) of the fish stocked at densities of 25, 50 and 75 fish/m3 cage were 828.0±1.83g, 774.0±20.18g and 693.0±34.20g. The corresponding mean values of Specific Growth Rate were 3.33, 3.25 and 3.43. Temperatures ranged between 24.50C - 32.60C while salinity ranged between 24 - 95ppm. The Feed Conversion Ratio (FCR) was 4.99, 4.73, and 3.43, and cumulative survival rates were calculated as 99.84, 99.66 and 99.50% respectively. The results revealed that stocking density had a significant (P>0.05) effect on growth and survival rates of Clarias gariepinus. Fish held at the highest stocking density exhibited the lowest growth and survival rate. Cages with 50fish/m3 stocking density had the best production with total final weight (38.67Kg) and profit index (3.27) compared to other treatments (P>0.05).Keywords: Stocking density, bamboo-net cages, profit index, survival, growth, Clarias gariepinu

Behavioural and Some Physiological Assessment of Glyphosate and Paraquat Toxicity to Juveniles of African Catfish, Clarias gariepinus

The impact of acute exposure of Clarias gariepinus juveniles to commonly used herbicides, glyphosate and paraquat was evaluated through changes in fish behaviour and mortality. Juveniles of the African catfish were exposed to varying acute concentrations of glyphosate and paraquat. The fishes responded, exhibiting different behavioural abnormalities like hyperactivity, abnormal swimming, restlessness, loss of equilibrum and haemorrhage. Observation of opercular ventilation count (OVC), tail fin movemant rate (TMR) and air gulping index (AGI) showed a marked difference between control and exposed fishes, indicating that the herbicides negatively impact on these parameters. These behavioural and morphological anomalies became more pronounced with increasing concentrations of the herbicides. Mortality was also observed to be concentration dependent. After 96 h of exposure, the 96hr LC50 for paraquat was found to be 0.07mg/L while that of glyphosate was found to be 0.530mg/L. The result revealed that glyphosate and paraquat have the ability to induce unusual behaviours in fish and can therefore serve as reliable indicators of toxicity in environmental impact assessment programme

Study of ichtyofauna of Daberam Reservoir, Katsina State

Research was carried out to explore the fish species diversity and study some aspects of the Biology of fish of Daberam reservoir, Katsina state, for a period of three month from March to May 2009. 66 Samples of fish were collected from commercial fishermen and experimental fishing gears, preserved in formalin and taken to laboratory for identification. Seven genera comprising eleven species were identified. The regression coefficient (b) were 3.07, 2.91 and 3.21 for the three most commercially importance species in the reservoir i.e. Oreochromis niloticus, Tilapia zilli and Clarias gariepinus respectively, the results indicated Positive allometric growth for O. niloticus and C. gariepinus and negative allometric growth for T. zilli. The mean condition factor (k) was 1.140, with values of 1.027, 1.660, and 0.732 for O. niloticus, T. zilli and C. gariepinus respectively. This result indicates that the fish are not leaving well compared to other freshwater fishes. Key words: Daberam reservoir, fishdiversity, allometric growth, condition facto

Behavioural and Some Physiological Assessment of Glyphosate and Paraquat Toxicity to Juveniles of African Catfish, Clarias gariepinus

The impact of acute exposure of Clarias gariepinus juveniles to commonly used herbicides, glyphosate and paraquat was evaluated through changes in fish behaviour and mortality. Juveniles of the African catfish were exposed to varying acute concentrations of glyphosate and paraquat. The fishes responded, exhibiting different behavioural abnormalities like hyperactivity, abnormal swimming, restlessness, loss of equilibrum and haemorrhage. Observation of opercular ventilation count (OVC), tail fin movemant rate (TMR) and air gulping index (AGI) showed a marked difference between control and exposed fishes, indicating that the herbicides negatively impact on these parameters. These behavioural and morphological anomalies became more pronounced with increasing concentrations of the herbicides. Mortality was also observed to be concentration dependent. After 96 h of exposure, the 96hr LC50 for paraquat was found to be 0.07mg/L while that of glyphosate was found to be 0.530mg/L. The result revealed that glyphosate and paraquat have the ability to induce unusual behaviours in fish and can therefore serve as reliable indicators of toxicity in environmental impact assessment programme

A survey for the presence of microcystins in aquaculture ponds in Zaria, Northern-Nigeria: Possible public health implication

Aquaculture ponds in Zaria, Nigeria, were screened for the occurrence of the hepatotoxic microcystins using an ELISA method. Four genera of cyanobacteria (Microcystis, Nostoc, Planktothrix and Anabaena) were recorded from 11 aquaculture ponds screened. These cyanobacteria are generallyknown to produce microcystins and other bioactive substances. Six of the 11 aquaculture ponds had detectable concentrations of microcystins (ranging from 0.6 to 5.89 ìg/L). This means that there is the possibility of bioaccumulation of microcystins in fish. The implication of this is that people that feed on contaminated fish from these ponds stand the risk of microcystins poisoning

Acute toxicity of glyphosate and paraquat to the African catfish (Clarias gariepinus, Teugels 1986) using some biochemical indicators

The impact of acute exposure of Clarias gariepinus juveniles to commonly used herbicides, glyphosate and paraquat was evaluated through changes in fish mortality and biochemical indeces. Juveniles of the African catfish were exposed to varying acute concentration of glyphosate and paraquat. After 96 h of exposure, the 96 h LC50 for paraquat was found to be 0.07 mg/l while that of glyphosate was found to be 0.530 mg/l. After the exposure period, some enzymes were assayed for in fish liver using a combination of conventional methods and commercially available kits. Comparing with the control, ANOVA analysis revealed that there were significant (p < 0.05) increases in the activities of all enzymes assayed for alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH) and alkaline phosphatase (ALP). There were also significant (p < 0.05) increases in the activities of the antioxidant enzymes: catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx) and in lipid peroxidation, which was measured by thiobarbituric acid substances (TBARS). The result revealed that glyphosate and paraquat have the ability to modulate certain fish biochemical parameters and can therefore serve as reliable indicators of toxicity in environmental impact assessment programmes

Responses of the African catfish Clarias gariepinus to long-term exposure to glyphosate- and paraquat-based herbicides

Direct and indirect contamination of the aquatic environment by pesticides results in a decrease in fish productivity and may elevate concentrations of undesirable chemicals in edible fish tissues. The effects of long-term exposure of Clarias gariepinus juveniles to sublethal concentrations of glyphosate and paraquat, two commonly used herbicides, for eight weeks were investigated using three concentrations of the 96 h LC50 of each herbicide: 3.5, 7 and 14 μg l−1 for paraquat, and 26.5, 53 and 106 μg l−1 for glyphosate. Enzyme assay and histological analysis were conducted every fortnight. Significant increases in the activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), alkaline phosphatase (ALP) and hepatocyte vacuolation in the livers of the exposed fish confirms the toxicity of the herbicides, and thus could be useful tools in environmental monitoring

Relative contribution of hookworm and Ascaris lumbricoides to iron deficiency anemia among school pupils in Nasarawa area, Nigeria

Stool and blood specimens of 418 school pupils were examined for intestinal parasites and iron deficiency anemia respectively, using rapid field epidemiological techniques. 156 (37.3%) of the pupils were infected with different species of intestinal parasites. More than forty-six percent (46.8%) of the infected individuals were anemic. Hookworm (28.8%) and Ascaris lumbricoides (16.7%) were the dominant helminthes encountered. Cases of mixed infection with these dominant species and other intestinal parasites were also documented. The overall prevalence of anemia (38.8%) in this community was high. Pupils with cases of mixed infection (hookworm and A. lumbricoides) were more anemic than those with single infections of hookworm and A. lumbricoides. Both hookworm and A. lumbricoides proved to contribute significantly to anemia in the area. A linear relationship was observed between parasite infection, anemia and weight of the pupils, but this was not statistically significant. Keywords: Hookworm; Ascaris; anemia; school pupils; NigeriaInternational Journal of Natural and Applied Sciences Vol. 2 (3) 2006: pp 205-20