Description

Abstract: Results of experiment in Cycle III of the Pond Dynamics/Aquaculture CRSP are reported here. Two experiments were conducted: one lasted 156 days and the other lasted 149 days. During both experiments four levels of dried chicken manure (12.5, 25, 50 and 100 g/m2/wk) were added to 0.02 ha ponds. There were three ponds in each treatment. Results of the two experiments were similar. Yield of Nile tilapia (Oreochromis niloticus) at final harvest increased linearly with increasing fertilizer application from about 900 kg/ha in the lowest treatment to approximately 2300 kg/ha in the highest. Increased algal productivity and an apparent increase in detritus accompanied increasing fish yield. Analyses of nitrogen and phosphorus suggested that higher algal productivity and fish yields could be obtained by improving the fertilizer regime so that N and P are available in these ponds in proportions required by pond mircroflora.