Aquaponics

The term aquaponics is a combination of "aquaculture" and "hydroponics". It describes an agricultural production system in which the breeding of fish in a circuit-based aquaculture unit is combined with the hydroponic cultivation of crops. A familiar example is the “Tomatofish” which is a research project on the interaction of tilapia, a genus of African cichlid, and tomato plants, funded by the German Federal Ministry of Education and Research (BMBF).[1]

The approach of aquaponics allows to have a year-round, resource saving production of food fish and agricultural crops and thereby contributes to food security. Conventional aquaculture systems as well as the production of vegetables in green houses can have negative effects on the environment due to nutrient leaching, water pollution and eutrophication.[2] Aquaponics systems, in contrast, target to have synergy effects through connecting closed aquaculture recirculation systems with hydroponic plant farming.[3] The system runs by using the fish excretion – which is purified by a biofilter – and carbon dioxide exhaled by the fish as fertilizer for the plants. A valve enables the adjustment of the nutrient concentration to the requirements of the plants. The evaporated water of the plants is subsequently returned to the fish circulatory. This reduces the daily need for freshwater to less than three percent.[4] The water usage is therefore reduced by up to 90 percent compared to conventional cropping systems.[5] Another advantage of urban aquaponics is that regional marketing allows to reduce food imports and hence emissions from transport.[6] 

At the moment aquaponic projects have to deal with high investment, operating and production costs [9] and with difficulties in selecting suitable plant varieties.

The objective of aquaponics is to enable a year-round, resource-saving production of food fish and agricultural crops. The connection of a closed aquaculture cycle for fish farming with a hydroponic facility for crop production and the utilisation of synergy effects between the two systems make it an innovative concept. This allows to prevent common disadvantages of conventional aquaculture like water pollution and eutrophication. At the same time it has the potential to promote regional economic cycles. Nevertheless there are still barriers like high investment, operating and production costs. Those barriers currently confine the development of this niche innovation.