Aquaponics is a productive technique that combines the production of aquatic organisms (aquaculture) with horticultural production in crops without soil (hydroponics), so that the metabolic wastes of the first system, once transformed by a community of associated bacteria, are used as fertilizers in the second. This productive synergy allows significant savings in water and fertilizers, as well as substantial advantages for the environment, as it does not require high inputs or cause potentially polluting discharges. It could be said that this system approaches the paradigm of the circular economy, by promoting the reuse of nutrients, water, etc. between the different components of the system, minimizing the use of external resources.
In an aquaponic system, plants use metabolic waste from fish and unconsumed feed, transformed by a bacterial community into nutrients easily assimilated by them (nitrates, phosphates), to grow. With the extraction carried out by their root system, they purify the water from excess nitrates and phosphates, maintaining adequate levels for the development of fish and reducing water consumption and potential degradation of the environment.
The presence in the same environment of three biological populations (plants, fish and microorganisms responsible for mineralization) with different requirements and multiple interrelationships between them, makes it impossible to use pesticides, antibiotics and other substances that could have negative effects on the health of consumers or on the environment, which is why it is usually circumscribed within the framework of sustainable and healthy productions. This system reproduces the cycle of mineralization of organic matter in nature under controlled conditions, also producing food for humans in the form of fish and plants. For this reason, aquaponics is presented as an interesting alternative for the implementation of production systems based on the circular economy (reduce, reuse, reuse), compared to the classic ones based on the linear economy (extraction, manufacture, use, elimination). With this new system it is possible to avoid some of the problems associated with conventional aquaculture (potential contamination of aquifers with effluents, overexploitation of extractive fishing to make fish feed, water consumption, etc.) and agriculture (limitation of fertilizers such as phosphorous, waste of water, excessive use of pesticides and fossil fuels, etc.).
All these advantages of aquaponic systems allow obtaining very healthy and high quality vegetables and fish, which in many countries are already certified as sustainable and ecological production. Aquaponic systems also have a great potential to contribute to family self-consumption and food sovereignty, driven through small-scale and low-cost systems.