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No Thumbnail AvailableProjectThe effect of liquid petroleum refinery effluent on fingerlings of Sarotherodon melanotheron (Ruppel 1852) and Oreochromis niloticus (Linnaeus 1757)
Establishment of African Regional Aquaculture Centre
1987Also available in:
No results found.The toxicity of petroleum refinery effluent from Alesa-Eleme (Port Harcourt) Refinery, to two tilapia species, Oreochromis niloticus and Sarotherodon melanotheron, fresh and brackish water species respectively were investigated at an average temperature of 27°C ± 2.5°C under laboratory conditions. LT50 values increased from 29' minutes at 100% effluent concentration to 645 minutes at 10% effluent concentration (Vol/Vol) for O. niloticus and from 48 minutes at 100% to 1,917 minutes at 10% for S. melanotheron. Toxicity of effluent to fish decreased as the effluent aged. LT50 for 2-day and 6-day old effluent for O. niloticus at 63.1% effluent concentration were 30 and 70 minutes respectively. Median lethal concentrations (LC50) obtained from regressions of effluent concentrations and median lethal times (LT50) for 6-day old effluent at 24, 48 and 96 hours were 5.6, 3.29 and 1.93 percent respectively for O. niloticus, while the corresponding values for S. melanotheron were 9.48, 5.83 and 3.6% respectively. The safe concentrations of 6 and 15-day old effluents were estimated as 0.19 and 0.29% respectively for O. niloticus, while the corresponding values were 0.36 and 0.35 for S. melanotheron. The 24 and 48 hours LC50 values show that S. melanotheron is more resistant to oil refinery effluent than O. niloticus. -
No Thumbnail AvailableProjectInfluence of ambient oxygen on feeding and growth of the tilapia, Oreochromis niloticus (Linnaeus)
Establishment of African Regional Aquaculture Centre
1987Also available in:
No results found.Oreochromis niloticus (8.1 ± 0.5 g) grown in fresh water at 28 ± 2C for 35 days at various ambient oxygen concentrations, below air saturation in static water aquaria, were seriously affected in their feeding, assimilation and growth by ambient oxygen. While the ambient oxygen maintained was reduced from about 90% air saturation (about 7 mg/l) to about 20% air saturation (about 1.5 mg/l) food consumed and assimilated decreased 40 and 60% respectively. Correspondingly, assimilation efficiency dec reased from 80 to 50%, and conversion efficiency from 15 to 5%, while uncorrected FCR increased from 1.45 to 6.75. Under a simulated diel flux of oxygen (from about 20 to 200% air saturation) brought about by an induced bloom of plankton, growth rate of O. niloticus was considerably reduced when compared with those maintained at DO near saturation constantly. The present results suggest that DO levels below about 50% air saturation and diel flux of DO, often prevalent in tropical fish ponds tr eated with high doses of organic/inorganic fertilizers, would cause considerable reduction in pond production of tilapias. -
Book (stand-alone)The potential of farming tilapia (Oreochromis niloticus) and freshwater prawn (Macrobrachium rosenbergii) in Vanuatu 2004
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No results found.Under the auspices of the Food and Agriculture Organization of the United Nations (FAO) Sub-Regional Office for the Pacific Islands (SAPA) in Samoa, a feasibility study on farming tilapia and prawns was undertaken by SPC Aquaculture Office in November 2003. The objectives were to survey the potential to develop Tilapia (Oreochromis niloticus) and Prawn (Macrobrachium rosenbergii) farming in Vanuatu (further details are given in the Terms of References in Appendix 2).
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