Assessment of fish culture water improvement through the integration of hydroponically grown lettuce

Water quality improvement through the integration of hydroponically grown l ettuce into fish culture systems was assessed and nutrient concentration mo nitored throughout the production cycle. The experimental work consisted of two fish culture systems. One integrated with lettuce and a conventional f ish culture system (without lettuce), was replicated two times. Fish were f ed four times daily 1.2% of total biomass with a high protein (45%) feed co ntent. Systems water renewal were calculated based on a mass balance approa ch for nitrates which is likely to accumulate beyond recommended levels for fish culture. Apart from iron, as iron chelate which was weekly supplement ed to concentration levels of 2mg/l, all the other nutrients resulted from the fish culture water. Water samples were taken on a regular basis through -out the production cycle and results compared. Results suggest that throug h the incorporation of lettuce into the system, considerable water savings can he achieved where nitrates concentration was 20-27% less in the integra ted system.