Antibiogram of faecal Streptococci isolates for pollution source determination in the Ikpoba river, Benin City

Water samples from various sites of the Ikpoba River, Benin City, were bacteriologically analysed to determine bacterial indicators of faecal pollution and heterotrophic bacterial concentration. Sampling points 1 was the point of drainage discharge from the University of Benin Teaching Hospital, 2 was at the Bridge at Upper Mission Road, 3 was the point of effluent discharge from Oredo Local Government Area Abbatoir, 4 was at the Bridge along Benin-Agbor Road and 5 was the point of effluent discharge from Guinness Nigeria PLC. Faecal coliform count was generally high in all sample sites with the point of discharge of effluent from the Abbatoir showing the highest mean count of 1.51 × 107 cfu/ml; and the Bridge at Upper Mission Road had the lowest mean count of 1.20 × 107 cfu/ml. Faecal streptococci count was highest at the point of discharge of effluent from Guinness Nigeria PLC at 8.21 × 107 cfu/ml. while the Bridge at Upper Mission Road had the lowest faecal streptococcus count of 5.83 × 106 cfu/ml. Antibiotic Resistance Patterns of faecal streptococci isolates on day 1 were observed to be more susceptible to the battery of antibiotics than faecal streptococci isolates on days 2 and 3. The results of the ratio of faecal coliform to faecal streptococci and the antibiotic resistance pattern on faecal streptococci showed that faecal pollution of the Ikpoba River has both human and animal origin. There are undoubted risks to human health from surface water polluted with animal faeces, nevertheless, it is human faeces that represent a much greater risk and thus constant investigations should be carried out by environment monitoring agencies to evaluate the pollution status of the river and residents around the river should administer filtration techniques before domestic use. Keywords: faecal pollution, faecal streptococci, antibiotic resistance patterns

Water renewal in static systems: Impacts on productivity and survival in Clarias gariepinus (Burchell, 1822)

The impact of water renewal in a static system on the growth and survival of Clarias gariepinus fingerlings was investigated under six different treatments, namely: T1 (daily water renewal), T3 (three days water renewal), T5 (five days water renewal), T7 (seven days water renewal), T9 (nine days water renewal) and T14 (fourteen days water renewal). Results showed that growth performance and survival was significantly (P< 0.05) affected by the water renewal frequencies. After six weeks, weight gain, daily weight gain, specific growth rate, final body weight, was significantly higher in T5 (P< 0.001). Likewise, survival in T5 was significantly higher compared to other groups (P< 0.001). For all evaluated parameters, T14 had the least performance. Slow response to feeding, slow movement and hanging on the water surface was observed in T9 and T14. Daily water renewal tank had significantly (p < 0.05) higher dissolved oxygen (04.52 mg L-1) while electrical conductivity (800.00 μScm-1) was significantly higher in T14 (P< 0.001). From the result, the growth and survival of the catfish fingerlings in T5 are superior to other renewal regimes. Therefore, for optimum growth and productivity of African catfish fingerlings reared in a static system, it is recommended that water renewal be performed every five days. Key words: Clarias gariepinus, water renewal, weight gain, water quality, behaviour, feed conversion ratio, specific growth rate

Acute toxicity of Jatropha curcas (barbados nut) latex extracts to Oreochromis niloticus juveniles

The effects of the latex extract of Jatropha curcas on mortality rate, opercular ventilation rate and some behavioural responses of Oreochromis niloticus juveniles were investigated under laboratory conditions over a 96 hours exposure period. Juveniles of Oreochromis niloticus (Trewavas) were exposed in plastic aquaria to 0.00mg.l-1 (control), 10mg.l-1, 15mg.l-1, 20mg.l-1, 25mg.l-1 and 30mg.l-1. Their opercular beats per minute, tail fin beats per minute, mortality and probit kill were determined. Symptoms of toxicosis observed include agitated swimming, loss of equilibrium, air gulping, periods of quiescence and death. Within 24 hours the opercular ventilation beats and tail fin beats of the exposed fish were significantly higher than in control fish (p<0.05). At 72 hours and 96 hours the opercular and tailfin beats in the control fish were significantly higher (P<0.05) than the exposed fish. The 96 hours LC50 was determined as 5.23 ml/l. Include significance of this study to conclude abstract. Key words: acute toxicity, Jatropha curcas latex extract, Oreochromis niloticus, haematological parameters.

Effects of light matrix organics (probiotic) on the growth, feed digestibility, carcass and blood parameters of African catfish, Clarias gariepinus

Cameroon’s fish protein consumption levels remain inadequate due to low fish production. The effects of Light Matrix Organics (LMO), a probiotic combination on the growth performance, feed digestibility, blood and carcass composition of the African catfish, Clarias gariepinus were investigated. Probiotics are live microorganisms which when administered in adequate amounts confer health benefits on the host. A basal diet was formulated and supplemented with LMO at 0.0 ml/kg (T0) as control; 1.66 ml/kg (T1); 2.49 ml/kg (T2); 3.32 ml/kg (T3) and 4.15 ml/kg (T4) and fed to 340 Clarias gariepinus fingerlings in two blocks (with average fish weights of 1.00±0.40 g and 0.1±0.05 g respectively), for sixty (60) days in replicate plastic tanks. Fish were fed twice daily at 4% body weight. Results show that the Mean weight gain, Specific growth rate and Protein efficiency ratio were significantly highest (P<0.05) in fish fed diets supplemented with LMO at 4.15 ml/kg (T4) and lowest in T0 (control). Apparent Digestibility Coefficients (ADC) of C. gariepinus for Dry Matter% and Crude Protein% decreased significantly in the general order: T4>T3>T2>T1>T0, except for Crude Protein which was significantly higher (P<0.05) in T3 than in T4. ADC Lipid% was higher (P<0.05) in both T2 and T4 than in all other treatments while ADC Energy was highest (P<0.05) in T2. Blood parameters were significantly higher (P<0.05) in LMO supplemented diets except for haematocrit (Ht) and red blood cells (RBC). Carcass nutrients differed significantly with LMO supplemented diets producing significantly lower (P≤0.05) fat but storing more energy than fish on the control diet. Incorporating LMO in treatment T2 was significantly more (P<0.05) economically efficient than other treatments. The supplementary use of LMO at the rate of 2.49ml/kg fish feed is therefore recommended based on the high economic efficiency and above average growth performance. Key words: probotic, light matrix organics, Clarias gariepinus, growth performance, digestibility, economic efficiency.

Biotreatment of brewery effluents for aquaculture use using autochthonous fungi

The potential of reducing environmental impact of untreated brewery effluent was investigated. Although concentrations of pollutants in such effluents are usually considered low and inadvertently discharged into adjacent urban drainage facility, mycoremediation to remove dissolved inorganic nutrients in effluent was conducted with a view for aquaculture use in Uyo metropolis, southeast Nigeria. Raw brewery effluents were obtained and screened for indigenous microbial flora. Autochthonous fungi isolated included Aspergillus niger, Verticillium sp. and Mucor sp. The potential use of isolates as alternative treatment of brewery effluents was analyzed for treated and control groups. Treated group was inoculated with pure colonies of fungi isolates while the control group received no fungi treatment or modification. Both groups were incubated for seven (7) days. Thereafter, the physicochemical parameters of raw and remediated effluents were analysed and compared with National Environmental Standards and Regulations Enforcement Agency (NESREA) and aquaculture standards. Results confirmed suitability of autochthonous fungi isolates in mycoremediation of brewery effluent for aquaculture and irrigation. Key words: effluent toxicity, industrial pollution, mycoremediation, aquatic ecosystem, Uyo

Food items and feeding habits of two Nothobranchiidae, Epiplatys chaperi sheljuzhkoi (poll, 1953) and Nimbapanchax petersi (sauvage, 1882) in Banco river, Côte d’ivoire

Food and feeding habits of two Nothobranchiidae species, Epiplatys chaperi sheljuzhkoi (Poll, 1953) and Nimbapanchax petersi (Sauvage, 1882) from Banco River were investigated between January and December 2016. Stomach contents of 119 and 397 individuals of E. sheljuzhkoi and N. petersi were respectively analyzed, ranging in size from 13 and 55 mm, 11 and 48 mm standard Length, respectively. Formicidae being terrestrial insects, constituted the main prey (RI>50) of both species, and aquatic insect larvae (Hydrophilidae and Chironomidae) were secondary or accessory preys. The food items in stomach showed a small spectrum in E. sheljuzhkoi than N. petersi but differences were not significant (Chi-square, p>0.05). Diet composition of both species showed little variation according to seasons, sampling zones and size groups (Anova, p>0.05). However, a decreasing trend in terrestrial insects and an increase of other preys in stomach contents has been observed from upstream to downstream. For ontogenic variation, large specimens group fed much more on aquatic insect larvae, fish scales and macrophytes than small size group. This work indicated that both species fed on a small range of prey items dominated by insects in Banco River and could be considered strict insectivorous predators. This work concludes that both species have similar diets and the canopy cover of Banco forest plays an important role in the feeding and conservation of these species. Key words: Epiplatys, Nimbapanchax, canopy cover, diet, terrestrial insects, Formicidae, predator.

Boosting fish production in Cameroon: Incorporated fish-rice farming versus earthen pond fish culture in Buea, Mount Cameroon region

Wetland incorporated fish-rice farming (FRF) is a possible solution to the problem of high costs of fish feeds in aquaculture in Cameroon. For 12 weeks, at the University of the Buea (UB) the growth of the fish, Clarias gariepinus in concurrent culture with rice (Oryza sativa, L.) in two rice plots (rice plot 1 and rice plot 2stocking sites) in the University of Buea wetland and in two earthen ponds (fish pond 1 and fish pond 2stocking sites) fed compounded diet at 5% body weight was investigated. Physico-chemical water quality parameters of all the fish culture sites were monitored. Mean fish weight gain was significantly higher (P<0.01) in the wetland rice plots (329.21±44.35g) than in the two earthen ponds (30.01±2.84g). Apart from low mean dissolved oxygen values in the rice plot 1 (3.14±1.19 mg/L) and rice plot 2 (2.18±0.23 mg/L), mean values for physico-chemical water quality parameters were within recommended ranges for C. gariepinus growth in all the four culture sites. This FRF experiment proved a better practice in fish growth than the conventional earthen pond culture in Buea, Cameroon. Its adoption by local fish farmers is recommended. Keywords: Wetland integrated fish-rice farming, C gariepinus, earthen pond culture, and fishpond.

Helminth parasites of cultured Clarias gariepinus and Tilapia zillii in Uyo, Akwa Ibom State, Nigeria

The study examined helminth parasites of cultured Clarias gariepinus and Tilapia zillii in Uyo, Akwa Ibom State. A total of 60 fish samples (30 each of C.gariepinus and T. zillii) were subjected to parasitological examinations. Results revealed a total of 47(78.33%) fishes infected with various species of parasites: Nematodes (Camallanus polypteri, Paracamallanus cyathopharynx, and Procamallanus laevionchus), Cestodes (Polyonchobothrium torulosus and P. clariae) and Trematodes (Dactylogyrus extensus and Glossiduim pedatum) in decreasing order of abundance. Out of the 60 fish samples examined, 47 were infected with 219 parasites: 142(64.84%) nematodes, 40(18.26%) cestodes and 37(16.89%) trematodes. A total of 159(72.60%) parasites were recovered from C. gariepinus out of which 103(64.78%) were nematodes, 19(18.45%) were cestodes and 37(35.92%) were trematodes. While 60(27.40%) parasites were recovered from T. zilli, of which 39(65.00%) were nematodes and 21(35.00%) cestodes. No trematode was observed in the tilapia. The overall prevalence of parasitic infection was 78.33%. The results of chi square analysis showed that females of both species had significantly higher (P<0.05) prevalence of infection 27(84.4%) than males 20(71.4%). Also, C. gariepinus had higher infection rate of 25(83.33%) when compared to 22(73.33%) recorded in T. zillii. Key words: fish parasites, aquaculture, prevalence, C. gariepinus, T. zillii

Linkages between catchment characteristics and river water chemistry at the locality scale in the Ikpoba River, Southern Nigeria

This study explored the linkages between catchment characteristics (topography, land cover, soil and geology), average water chemistry (pH, calcium, magnesium, sulphate, nitrate, ammonium, orthophosphate, iron, zinc and lead) and rainfall in the Ikpoba River catchment, southern Nigeria, using statistical and locality-based GIS analyses. The results show that sites with high rainfall and percentage cover of arable and sand-gravel-clay lithologies were characterized by high acidity. There were strong links between average nutrient (𝑃𝑂43−-P, 𝑁𝐻4+-N and 𝑁𝑂3−-N) concentrations and diffuse agricultural sources in the catchment. Rainfall was strongly related to 𝑆𝑂42−, 𝑃𝑂43−-P and 𝑁𝐻4+-N suggesting that atmospheric deposition may influence their riverine concentrations. Results also suggest that decomposition of organic matter from forest stands was a significant driver of nutrient concentrations. Although metals (Fe2+ and Zn2+) were positively related to bedrock geology of sand-gravel-clay, there was no clear link between Pb2+ and the catchment characteristics investigated. Wetlands was found to be attenuating river water chemistry especially 𝑆𝑂42−, 𝑃𝑂43−-P and 𝑁𝐻4+-N concentrations. To underpin current environmental protection strategies, there is need to integrate a GIS-based analysis approach with monitoring data to fully identify the variability patterns in river water chemistry dynamics at local and multiple scales of water resource management in Nigeria. Key words: river catchment, water quality, metals, nutrients, GIS.

Effects of sub-lethal concentrations of corexit 9500® dispersant on growth and condition factor of juvenile Clarias gariepinus (Burchell 1822), Rivers state, Nigeria

The effects of sub-lethal concentrations of Corexit 9500 on growth and condition factor of juveniles of Clarias gariepinus was investigated after 21days, in 2018. 160 fishes were used as test organisms with a loading of 10/treatment and were exposed to 0.00, 0.0125, 0.025 and 0.05 ml/L concentrations of Corexit 9500. Treatments were in triplicate and Complete Randomised Design was adopted. The growth in length and weight of C. gariepinus was significantly higher in the control than the test treatments (P<0.05). The increase in weight of the control was significantly different from the three treatments. Temperature was not significantly different (P>0.05); however, the DO of control was significantly higher (P < 0.05) than that of the treatments, with the lowest DO in the 0.05ml/l treatment. pH was acidic for all treatments including the control but was more acidic with increasing concentration of Corexit 9500. The pH value for each treatment was significantly different (P<0.05). The conductivity was significantly different from each other (P<0.05) with higher values at the 0.025 ml/L concentrations. The condition factor (K) decreased with increasing toxicant concentration and was significantly different (P<0.05) at 0.0125ml/L and at Weeks 2 and 3 of 0.05 ml/L. Corexit 9500 dispersants should be appropriately assessed before deployment, and their use near fish breeding grounds should be avoided. Key words: Clarias gariepinus, dispersant, growth, physicochemical parameters, sub-lethal