No abstract

This study examined the effectiveness of Moringa oleifera fresh root-bark extract as an organic piscicide to control predatory fish in ponds. Acute-lethal toxicity (LC 50 ) of Moringa oleifera extract for 96-h exposure for Oreochromis niloticus fingerlings was determined at 26.45 mg l -1 . The extract was more toxic at higher concentrations of 100 mg l -1 , with fingerlings showing abnormal swimming, restlessness and uncoordinated behaviour before death. Moringa oleifera extract could be used as an organic piscicide in aquaculture pond management. Baseline information on its toxicity to fish could serve as a tool in fisheries management to wipe out predatory fish in ponds prior to stocking.

Aquaculture is one of the fastest growing food production sectors to every household in Nigeria. Products from aquaculture such as fish food supply protein to household protein. However, biosafety of food products from aquaculture is now considered as public health concern in Nigeria. This is due to the nature and component of materials used as rearing facilities on the fish farm. Elimination of unwanted fishes and other predators is a common practice among fish farmers in Nigeria prior to stocking of desirable fish fingerlings. The use of synthetic pesticides to eliminate unwanted fishes and other predators in pond is persistent and could get into the food chain. Thus, the use of environmentally safe natural pesticides as an alternative is being embraced in aquaculture because they have a short time of toxicity disappearance and biodegradable. This will enhance the principles of sustainable aquaculture production and its management in Nigeria. In Southwestern Nigeria, there is little or no information on commercial production of Moringa oleifera for aquaculture purpose. There is the need for future development on Moringa production on commercial scale in Southwestern Nigeria and elsewhere in the tropics for sustainable aquaculture development. The paper therefore reviewed possible guide to Moringa oleifera production, methodology for its potential application in sustainable aquaculture development in Southwestern Nigeria. Possible prospects and challenges to encounter during commercial production were discussed.

Moringa oleifera is an indigenous tree growing in Southwestern Nigeria for food and medicinal property. Therefore this study evaluates the preliminary toxicological screening of ichthyotoxic compounds in Moringa oleifera to freshwater fish, Oreochromis niloticus fingerlings. The morphological parts such as leaf, seed, stem-bark, pod (fruit), root-wood and root-bark were subjected to standard phytochemical screening method of plant metabolites. Screening done was just only to identify their presences and not quantify as limited to the current research. The Fresh Root-bark Hot Ethanolic Extract (FRBHEE) was toxicologically tested on fish fingerlings for-1 96hours.Acute toxicity concentrations obtained were 0, 10,17,31,56,100 where 0mgl served as control. The Median Lethal Concentration (LC) for Oreochromis niloticus fingerlings obtained 50-1-1 was 43.09 mgl with 95% upper and lower limit confidence interval between 74.78-28.65 mgl-1 respectively. High mortality was obtained at 100mgl of FRBHEE where fish behavioural changes such as rolling upward, backward swimming, sudden mucus secretion, haemorrhages, stiff fin rays and erratic collision on wall of the tank attested to ichthyotoxic property of FRBHEE. Therefore, ichthyotoxic compounds found in M.oleifera could further be quantified to know the exact grammes it's contained. FRBHEE could serve as organic piscicides in aquaculture pond management to wipe out predators prior to stocking of fish pond with desirable fish species.