Background Around 50% of the fishing products consumed in the world today come from aquaculture (FAO, 2010) and this percentage is set to gradually to increase. Marine aquaculture will increase its production by more than 20 times by 2050 (FAO). Over the coming years, however, developing countries will cease to be net exporters to the more developed countries (such as the EU Member States) and they will supply increasing amounts of food to their domestic markets. Nevertheless, the average consumption of fish products per inhabitant in the EU is 23.3 kg/year, considerably higher than the global average of 18 kg/year. These figures underscore the need to increase the number of aquaculture facilities in Europe to supply citizens with good quality food, without producing a negative impact on natural resources. The main environmental impacts of aquaculture relate to energy and water consumption, use of raw materials and eutrophication of water systems due to the discharge of pollutants. Objectives The main objective of AQUASEF is to demonstrate, promote and disseminate the use of efficient and innovative, low-emission technologies in the aquaculture sector, especially the inshore modality. In particular, the project will focus on implementing technologies to increase the environmental sustainability of the cultivation cycle of fishes and salt water molluscs, on reducing its carbon footprint and on improving the quality of water. Project measures will reduce the energy dependence of the facilities, the oxygen dependence of the tanks, and the overall environmental impact in water ecosystems through effluent treatment and CO2 fixation. Specifically, the project will demonstrate: The possibility of optimising energy consumption by implementing best management practices and using renewable energies for three power generators (two photovoltaic and one aeolian); The environmental advantages of using hydrogen and fuel cell technologies in the aquaculture sector. An electrolyser of 5 kW powered by renewable energies will be tested for the self-production of oxygen; Best practices for aeration and oxygenation in aquaculture – high efficiency aerators will be installed; and Possibilities of fixing the CO2 emitted by autoctonous microalgae cultivation. The project will demonstrate how microalgae have an added value as diet for fishes and molluscs and as a natural element in the purification of effluents. Expected results: Reduced GHG emissions from the aquaculture facility by 46.6 tonnes of CO2 per year by using renewable energy sources to cover at least 10% of the energy demand; Reduced GHG emissions by 56 tonnes CO2 per year through the implementation of energy-efficiency measures in the operation and control of the equipment, reducing the energy consumption of the plant by 20%; Increased efficiency by self-production of oxygen through renewable sources (hydrogen cell), producing energy savings of 15.878 kWh/year and reduced GHG emissions by 4.72 tonnes CO2 /year; Improved diet of fishes and molluscs thanks to the addition of microalgae making it unnecessary to supply additives, which generate residues on the water tanks; Fixed CO2 emitted in the gases combustion by canalising and supplying this CO2 to the microalgae cultivation tanks; and A good practice guide on the implementation of new technologies in aquaculture facilities.