Water Quality and Nutrient Aspects in Recirculating Aquaponic Production of the Freshwater Prawn, Macrobrachium rosenbergii and the Lettuce, Lactuca sativa

The purpose of this study was to investigate the effects of different nutrients and their ability to improve the production of Macrobrachium rosenbergii and Lactuca sativa in a prototype recirculating aquaponic (RA) system. Experimental units were set up with different amounts of supplemented organic and inorganic (complex minerals) nutrients to carry out the study. The results indicated that desirable growth of M. rosenbergii might be possible in RA systems when supplied sufficient levels of macro-micro nutrients. Analyses of nutrients in the prawn culture tanks demonstrated that ammonia and nitrate concentrations were critical in maintaining proper water quality during the culture period. Five-day biological oxygen demand (BOD5) increased significantly with the increased loading of organic supplement in the rearing tanks. A significant linear relationship of chlorophyll a and N:P ratio was observed among the treatments. The combination of complex minerals and organic chicken manure (CM15) displayed a higher N:P ratio, maximal total yield and did not show adverse effects of NH3 concentrations and other important water quality parameters.