The trace-Fossil Record of Major Evolutionary Events The Cambrian Explosion

Abstract

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