Growth and Nutrient Removal Efficiency of SweetWormwood (Artemisia annua) in a RecirculatingAquaculture System for Nile Tilapia(Oreochromis niloticus)

Abstract

The maintenance of optimal water quality for fish production is one of the major challengesin aquaculture. Aquaponic systems can improve the quality of water for fish by removing theundesirable wastes and in turn produce a second marketable crop. However, there is no informationon the growth and nutrient removal capability ofArtemisia annuain aquaponic systems. This studyevaluated the effect of plant density on water quality, the growth ofA. annuaandOreochromisniloticusin a small scale aquaponic system in Kenya. The aquaponic system consisted of threetreatments representing different plant densities (D1: 48 plants/m2, D2: 24 plants/m2and D3:0plants/m2). The high plant density system contributed significantly (p<0.05) to the removal ofall nutrients. The removal efficiency of ammonia was significantly higher in D1 (64.1±14.7%)than in D2 (44.5±6.8%) and D3 (38.0±12.1%). Nitrates and nitrites were inconsistent, whereasphosphorus increased gradually in all treatments. The productivity of plants was higher in D1 thanD2. Fish growth rates were significantly higher in D1 (0.35±0.03 g/d) and D2 (0.32±0.02 g/d) than inD3 (0.22±0.04 g/d). The results show thatA. annuacan be cultivated in aquaponic systems due to itsnitrogen removal capabilities