Quantifying waste excretion by Egyptian tilapia hybrid ( Oreochromis niloticus) and nutrient uptake by hydroponically grown plant species to optimize an integrated aquaculture system

The main objective of this thesis was to determine the most appropriate extractive species and environmental conditions for an integrated tilapia aquaculture system. This was achieved by quantifying waste excretion from an Egyptian Tilapia hybrid (Oreochromis niloticus) and nutrient uptake for hydroponically grown Grand Rapids Lettuce (Lactuca sativa ), Duchess Tomato (Lycopersicon esculentum) and Provider Bean (Phaseolus vulgaris).;In the hydroponic plant uptake experiments, ammonia removal increased significantly from 0 to 24h for all plant species at all ambient temperatures. The rate of ammonia uptake for each plant species did not exhibit an increasing trend across temperatures. Instead, the rate of ammonia uptake was highest at their reported ideal growing temperature. Grand Rapids Lettuce and Duchess Tomato removed significantly more ammonia (corrected for weight of the plants) than bean at all ambient temperatures. Phosphate removal fluctuated between each sampling interval at all ambient temperatures. Nitrate uptake was minimal over 24h but increased significantly after 5d in each plant species at 25°C. These results will provide the framework for future development of an integrated aquaculture system combining tilapia with high value North American greenhouse crops.;Tilapia waste excretion experiments revealed that ammonia concentration increased significantly from 0 to 24h at all water temperatures (15, 20, 25 and 30°C). The rate of total ammonia excretion of small tilapia (corrected for the weight of the fish) was significantly greater than large tilapia at all experimental water temperatures. For both size groups of tilapia, the rate of total ammonia excretion did not increase consistently with each 5°C increase in water temperature. Instead, ammonia excretion was greatest at 25°C for all tilapia. Nitrite and nitrate excretion was minimal for both size groups of tilapia. Phosphate excretion fluctuated between each sampling interval at all water temperatures and tilapia culture sizes.