The Hub has produced a series of videos, filmed during the training school lectures and field trips. These are freely available on YouTube to watch and share.
Networking opportunities afforded by the COST action have facilitated the publication of a number of collaborative research papers. The full list can be found here: COST FA1305 publications.
Training school videos
Training school 1: A film from the Training School ‘Aquaponic trials‘.
Training school 2: Playlist of ten films from ‘Essential aquaponics‘.
Training school 3: Playlist of ten films from ‘Commercial aquaponics‘.
Training school 4: Playlist of eight films from ‘Microbial roles and dynamics in aquaponics‘.
Training school 5: Playlist of six films from ‘Modelling nutrients, energy and growth in aquaponic systems‘.
Training school 6: Playlist of three films (more coming soon) from ‘Design, maintenance and risk management of aquaponics systems: Animal-plant production and fish processing‘.
Training school 7: Playlist of twelve films from ‘Aquaponics: Ergonomics and economics‘.
The following publications are the direct result of the networking opportunities afforded by this COST Action.
Towards commercial aquaponics: a review of systems, designs, scales and nomenclature
This paper provides a definitive definition of aquaponics, where the majority (> 50%) of the nutrients sustaining plant growth derives from waste originating from feeding aquatic organisms, and a classification of integrated aquaculture and aquaponic systems (open, domestic, demonstration, and commercial) and scales of production (≤ 50 m², > 50–≤ 100 m², > 100–≤ 500 m², > 500 m²). This enables authorities, customers, producers and all other stakeholders to distinguish between the various systems, to better understand their potentials and constraints, and to set priorities for business and regulations in order to transition RAS or integrated aquaculture into commercial aquaponic systems.
Nutrient management in aquaponics: Comparison of three approaches for cultivating lettuce, mint and mushroom herb
Aquaponic systems may not contain sufficient levels of nutrients for proper plant development and growth, and therefore supplements may be required. This study compared three identical aquaponic systems (A, B, and C) and one hydroponic system (D) growing lettuce, mint, and mushroom herbs. The aquaponic systems were stocked with Nile tilapia. System A only received nutrients derived from fish feed; system B received nutrients from fish feed as well as weekly supplements of micronutrients and Fe; system C received the same nutrients as B, as well as weekly supplements of the macronutrients, P and K; in system D, a hydroponic inorganic solution containing N, Ca, and the same nutrients as system C was added on a weekly basis. Lettuce achieved the highest yields in system C, mint in system B, and mushroom herb in systems A and B. The study demonstrates that the nutritional requirements of mint and mushroom herb make them suitable for aquaponic farming because they require low levels of supplement addition, and hence little management effort, resulting in minimal cost increases. While the addition of supplements accelerated lettuce growth, it reduced nutritional quality (polyphenols, nitrate content).
EU policies: Opportunities for aquaponics
The authors review different policies relevant to aquaponics in order to create a clear picture on how aquaponics can contribute to achieving European goals, and how the policies and strategies can provide support and opportunities for this sector. The information provided can be used by national government bodies, lobbyists and farm associations to further promote and develop aquaponics activities in the future.
Read more: EU policies: Opportunities for aquaponics
Analysis of aquaponics as an emerging technological innovation system
The authors propose a framework to analyze aquaponics as an emerging technological innovation system at the interface between existing fish and plant production systems. The analysis focuses on the EU, using Germany as an case study, but also considers worldwide developments. The approach is explorative based on a literature review and interviews with experts. The main findings are that stakeholders have different views regarding future development pathways. Knowledge to manage complex systems in the long term is needed, and it is still unclear how to design institutional conditions to deliver sustainable outcomes.
Life cycle assessment of a micro aquaponic system for educational purposes built using recovered material
The aims of this study were to build a low cost micro aquaponics system for use as a didactic tool using recovered material and evaluate its environmental impact, and to verify whether this micro model is representative of full-scale aquaponics systems in terms of water quality and water consumption. Both water quality and the average daily water consumption of the micro system were in line with data reported in literature for larger aquaponics systems. Life cycle analysis showed that the greatest environmental impacts arise from the materials used and energy consumption. The results showed that the micro aquaponic system reliably mimics a full-scale unit and that it is a teaching tool with a relatively low environmental impact.
Building a database of plant protecting agents for aquaponic systems
The vast majority of the commercially available chemical pesticides cannot be used in aquaponic systems because of their toxicity and environmental persistence. A recent paper reports on work in progress to build up a database of toxicity and ecotoxicity data for all registered pesticides.
Hydroponic systems and water management in aquaponics: a review
122 papers published between 1979 and 2017 were reviewed in order to assess the role of the design and management of the hydroponic component on the overall performance and water consumption of aquaponics systems. Although no unequivocal results were found, the nutrient film technique appears to be less efficient than medium-based or floating raft hydroponics. The best system performance, in terms of both fish and plant growth, as well as the highest nutrient removal from water, was achieved with a water flow of between 0.8 and 8.0 L min-1. Data on water consumption in aquaponics systems are scarce, and no correlation was found between the ratio of hydroponic unit surface/fish tank volume and water loss from the system. However, daily water loss was positively correlated with the hydroponic surface/fish tank volume ratio if the same experimental conditions and/or systems were compared. The type of plant species grown was found to influence daily water loss, whereas the water flow (reciprocating flood/drain cycle or constant flow) or hydroponic system type (medium-based, floating or nutrient film technique) had no effect.
Vegetable Intercropping in a Small-Scale Aquaponic System
This paper reports the results of the first study of an aquaponic system for pangasius production using lettuce intercropped with red chicory. The experiment was conducted in a greenhouse at the Zurich University of Applied Sciences using the nutrient film technique in nine small-scale aquaponic systems. Intercropping of lettuce and red chicory affected the typical taste of these vegetables by increasing the sweetness of lettuce and changing the ratio among bitter taste compounds in red chicory. These results suggest intercropping as a possible solution for improving vegetable quality in aquaponics.
Aquaponics: Toward a Sustainable Water-Based Production System?
Aquaponics is an emerging method of local food production worldwide, using closed integrated production systems to grow vegetables and fish in a variety of contexts, including urban environments. It may be defined as an integrated, quasi closed-loop, multi-trophic food production system, comprising a recirculating aquaculture system (RAS) and a hydroponic unit, ensuring high levels of water reuse and nutrient recycling. Aquaponics is typically a multidisciplinary topic, covering several domains, such as aquaculture (fish feed, fish health, fish yield, fish wellbeing, sludge waste, sludge mineralization, sludge reuse, etc.), hydroponics (plant yield and growth, plant nutrition, plant nutrition through sludge recirculation, plant protection, etc.), water (water quality, water waste, water recirculation, etc.), microbiology (biological properties, microbiota characterization, population dynamic, quorum sensing, etc.), engineering for industrial and domestic uses (elaboration of production systems, sizing, modelling, monitoring of the systems, monitoring of water and water quality, automation, etc.). The aim of this Special Issue of Water is to summarize and disseminate recent scientific findings in aquaponics. Special attention is paid to scientific progress leading to the development of a sustainable production system.
Access the special issue: Aquaponics
Strategic points in aquaponics
Global environmental, social and economic challenges drive the need for new and improved solutions for food production and consumption. Food production within a sustainability corridor requires innovations exceeding traditional paradigms, acknowledging the complexity arising from sustainability. However, there is a lack of knowledge about how to direct further activities, to develop technologies as potential solutions for questions related to climate change, loss of soil fertility and biodiversity, scarcity of resources, and shortage of drinking water. One approach that promises to address these problems is controlled environment agriculture. Aquaponics (AP) combines two technologies: recirculation aquaculture systems (RAS) and hydroponics (plant production in water, without soil) in a closed-loop system. One challenge to the development of this technology is the conversion of the toxic ammonium produced by the fish into nitrate, via bacteria in a biofilter, to provide nitrogen to the plants. However, as this Special Issue shows, there are many other challenges that need to be addressed if the goal of the technology is to contribute to more sustainable food production systems.
Read more: Strategic points in aquaponics
Commercial Aquaponics Approaching the European Market: To Consumers’ Perceptions of Aquaponics Products in Europe
This paper presents the results of a study whose main aim was to assess consumers’ knowledge about aquaponics and their acceptance of aquaponics products in different European regions. An on-line questionnaire was sent to members of the public in 16 European countries. The results confirm three different clusters of potential consumers of aquaponics products. They also suggest an urgent need for implementing integrated and holistic approaches involving all stakeholders in aquaponics, in order to define a marketing plan and efficient communication strategies. Public decision makers, in cooperation with aquaponics stakeholders, need to address the main institutional constraints, namely the introduction of aquaponics as an economic activity and the organic certification of aquaponics products.
Fish Welfare in Aquaponic Systems: Its Relation to Water Quality with an Emphasis on Feed and Faeces—A Review
This review examines fish welfare in relation to water quality, fish feed and fish waste and faeces. Water quality parameters are the primary environmental consideration for optimizing aquaponic production and for directly impacting fish welfare/health issues and plant needs. In aquaponic systems, the uptake of nutrients should be maximised for the healthy production of the plant biomass but without neglecting the best welfare conditions for the fish in terms of water quality. Measures to reduce the risks of the introduction or spread of diseases or infection and to increase biosecurity in aquaponics are also important. In addition, the possible impacts of allelochemicals, i.e., chemicals released by the plants, should be taken into account. Moreover, the effect of diet digestibility, faeces particle size and settling ratio on water quality should be carefully considered. As available information is very limited, research should be undertaken to better elucidate the relationship between appropriate levels of minerals needed by plants, and fish metabolism, health and welfare. It remains to be investigated whether and to what extent the concentrations of suspended solids that can be found in aquaponic systems can compromise the health of fish. Water quality, which directly affects fish health and well-being, is the key factor to be considered in all aquaponic systems.
Tomato productivity and quality in aquaponics: Comparison of three hydroponic methods
This study compares tomato yield, morphological (external) and biochemical (internal) fruit quality, and overall tomato plant vitality from three different HP systems (nutrient film technique, drip irrigation system, and floating raft culture) and examines the distribution of nutrients in different parts of the tomato plant. Three replicate AP systems were set up, each incorporating the three different HP systems coupled with a separate recirculating aquaculture unit growing Nile tilapia. The results showed that the choice of the cultivation system had little influence on most of the above-mentioned properties. Tomato fruit mineral content was found to be in similar range for N, P, K, Ca, Mg, Fe, and Zn as reported in the literature. Yield and fruit quality were similar in all three systems. However, the drip irrigation system did perform slightly better. The slightly higher oxygen radical absorbance capacity (ORAC) of the fruits grown in AP in comparison to commercially produced and supermarket derived tomatoes might indicate a potential for producing fruits with higher health value for humans.
Lettuce (Latuca sativa L. var Sucrine) growth performance in complemented solution encourages the development of decoupled aquaponics
This research focuses on the potential of using aquaponic solution complemented with mineral elements in order to increase yield. Lettuce plants were put into AeroFlo installations and exposed to hydroponic (HP), aquaponic (AP), or complemented aquaponic (CAP) solutions. The principal finding of this research was that AP and HP treatments exhibited similar (p > 0.05) plant growth, whereas the shoot weight of the CAP treatment showed a significant (p < 0.05) growth rate increase of 39% on average compared to the HP and AP treatments. Additionally, the root weight was similar (p > 0.05) in AP and CAP treatments, and both were significantly higher (p < 0.05) than that observed in the HP treatment. The results highlight the beneficial effect of recirculating aquaculture system (RAS) water on plant growth. The findings represent a further step toward developing decoupled aquaponic systems (i.e., two- or multi-loops) that have the potential to establish a more productive alternative to hydroponic systems. Microorganisms and dissolved organic matter are suspected to play an important role in RAS water for promoting plant roots and shoots growth.
Survey of aquaponics in Europe
International aquaponic production has increased over the past decade, but less is known about research activities and production facilities operating in Europe. We conducted an online survey to get a better idea about research and production in Europe, focusing on five areas of aquaponics (i.e., demographics, facilities used, fish and crops produced, funding sources, and personal or company priorities for further development). The 68 respondents were distributed among 21 European countries, 43% were working at a university, and 19% were commercial producers. Only 11.8% of those surveyed had sold fish or plants in the past 12 months. Most respondents were male (66.2%) and had a post-graduate degree (91.7%). Facilities were generally new (74.5% constructed after 2010) and self-designed. Production figures were modest, with less than 10 respondents producing more than 1000 kg of fish or plants per year (mostly tilapia or catfish and herbs or lettuce). Systems were often funded by government grants (35.3%). The great majority of respondents (80.4%) stated that aquaponics was not their main source of income. Most respondents prioritized using aquaponics for educational purposes, while few (25%) used it to produce their own food or improve their health. Questions related to personal knowledge about aquaponics underlined the need for more training about fish diseases and plant pests.
Read more: Survey of aquaponics in Europe
Nutrient supply of plants in aquaponics systems
In this preliminary article we present data on plant nutrient concentrations in aquaponics systems, and compare them with nutrient concentrations in ‘standard’ hydroponic solutions. Our data shows that the nutrient concentrations supplied by the fish in an aquaponics system are significantly lower for most nutrients compared to hydroponic systems. Nevertheless, plants do thrive in solutions that have lower nutrient levels compared to ‘standard’ hydroponic solutions. This is especially true for green leafy vegetables that rarely need additional nutrient supplements. We conclude that aquaponics systems require continuous monitoring of the chemical composition of the circulating water – especially for the potentially toxic component, ammonium – in order to provide adequate concentrations and ratios of nutrients. If certain plants do require nutrient supplements, we believe that ones based on organic substances would be most beneficial. However, protocols for the application of such nutrient amendments still need to be developed.
Navigating towards decoupled aquaponics systems: a system dynamics design approach
The classic working principle of aquaponics is that nutrient-rich water from an aquaculture unit is used to fertilise a hydroponic plant culture unit, which in turn cleanses the water that is returned to the aquaculture tanks. A known drawback is that a compromise away from optimal growing conditions for plants and fish must be achieved in order to produce both crops and fish in the same environmental conditions. The objective of this study was to develop a theoretical concept of a decoupled aquaponic system (DAPS) in order to predict water, nutrient (N and P), fish, sludge, and plant levels. This done by developing a dynamic aquaponic system model, using inputs from data found in the literature. The outputs from the model revealed the dependency of aquacultural water quality on the hydroponic evapotranspiration rate. This can be explained by the fact that DAPS is based on one-way flows, which result in accumulations of remineralized nutrients in the hydroponic component ensuring optimal conditions for the plants. The study also suggests that the size of the cultivation area should be based on P availability in the hydroponic component, as P is an exhaustible resource and has been identified as one of the main limiting factors for plant growth.
The effect of anaerobic and aerobic fish sludge supernatant on hydroponic lettuce
The mobilization of nutrients from fish sludge (faeces and uneaten feed) plays a key role in improving the sustainability of aquaponic systems. While several studies have documented the aerobic and anaerobic digestion performance of aquaculture sludge, the impact of the digestate on plant growth has yet to be understood. The present study examines the impact of either an aerobic or an anaerobic digestion effluent on lettuce plant growth, by enriching a mixture of aquaculture and tap water with supernatants from both aerobic and anaerobic batch reactors. The lettuce plants grown in the hydroponic system supplied with supernatant from an anaerobic reactor had significantly better performance with respect to weight gain compared with those in the system where supernatant from the aerobic reactor was added, as well as the control system. It can be hypothesized that this effect was caused by the presence of NH4+ as well as dissolved organic matter, plant growth promoting rhizobacteria and fungi, and humic acid, which are predominantly present in anaerobic effluents. This study should therefore be of value to researchers and practitioners wishing to further develop sludge remineralization in aquaponic systems.
On the sustainability of aquaponics
This paper provides a brief literature review of the sustainability aspects of aquaponics by discussing its social, environmental, and economic impacts in different settings, such as commercial or community based urban food production, industrial scale production in rural areas, small scale farming in developing countries, and educational systems. Due to the range of potential applications and settings, sustainability impacts need to be assessed on a case-by-case basis. Furthermore, the complexity within markets, value chains, communities, urban and rural infrastructure and policy settings means that further research and data acquisition is needed in order to be able to fully assess the sustainability of aquaponics.
Read more: On the sustainability of aquaponics
Challenges of sustainable and commercial aquaponics
The world is facing a number of serious problems of which population rise, climate change, soil degradation, water scarcity and food security are among the most important. Aquaponics, as a closed loop system consisting of hydroponics and aquaculture elements, could contribute to addressing these problems. However, there is a lack of quantitative research to support the development of economically feasible aquaponics systems. Although many studies have addressed some scientific aspects, there has been limited focus on commercial implementation. In this review paper, opportunities that have the potential to fill the gap between research and implementation of commercial aquaponic systems have been identified. The analysis shows that aquaponics is capable of being an important driver for the development of integrated food production systems. Arid regions suffering from water stress will particularly benefit from this technology being operated in a commercial environment.
Aquaponics business in Europe: some legal obstacles and solutions
The lack of dedicated and harmonized legislation for aquaponics in general, and urban aquaponics in particular, makes it difficult for entrepreneurs to formulate a business plan and to seek financial support from banks and investors. A dedicated working group of COST Action FA1305 ‘EU Aquaponics Hub’ therefore set out to gather information from its membership on the perceived impact of current legislation on entrepreneurial possibilities in developing commercial aquaponics in their own country. This paper summarizes the results of this survey and highlights the main obstacles and solutions identified in three main areas: administration, environment, and safety.
Analytical innovation system framework analysis on commercial aquaponics development in Europe
As aquaponics grows in popularity amongst researchers, with great strides being taken in R&D with large semi-commercial systems within institutions, commercial aquaponics has surfaced on the agenda for numbers of European entrepreneurs. However, several questions regarding the merging of best practice from the different production systems and optimizing the economic, environmental and social aspects of aquaponics still remain unanswered. An Analytical Innovation System Framework Analysis (AISFA) was carried out in order to determine the main hurdles and the potential for future commercialization of aquaponics. The framework facilitates the analysis of systems using six different elements to breakdown and describe the system: (1) Actors and Organization; (2) Interactions and Intermediaries; (3) Knowledge Base and Human Capital; (4) Technology and Demand; (5) Institutions and Politics and (6) Competition.
Plant protection in ecocycle-based agricultural systems: aquaponics as an example
This paper calls the attention to a particularly important issue in aquaponics which is often neglected until it is too late: the management of plant pests and diseases. Fish diseases and plant protection-related problems, once they appear, are extremely difficult to deal with. The recycling of water within the system hinders the use of most of the conventional methods of pest and disease control due to their adverse effects either to the fish or to the plants. As a result, aquaponics is one of the few plant production systems that cannot be operated without high proficiency in the non-chemical methods of integrated pest management (IPM). IPM methods are based on the prevention, monitoring and rapid identification of the pest(s) and disease(s), and their efficient control.
The EU Aquaponics Hub organized an international conference on aquaponics SMEs at the University of Murcia (ES) on 19 April 2017. The presentations from the ‘aquaponics.biz’ conference can be downloaded here:
Ivo Haenen – Lessons from the aquaponics facility at Uit de Eigen
Haissam Jijakli – Green solutions for urban and rural farming
Paul Rye Kledal – Circular economy based urban rooftop farm
Bent Egberg Mikkelsen – Assessing opportunities and challenges for using aquaponics among young people at school
Fernando Sustaeta – NerBreen decoupled aquaponic system
Ragnheidur Thorarinsdottir – Samraekt Laugarmyri – Growing together
Kyra Hoevenaars – Design of aquaponic systems
Georg Simhandl – Connected aquaponics systems
Antonio Paladino – Bioaqua Farm – A holistic approach
Maja Turnšek Hančič – Aquaponics in a Slovenian context
Vesna Miličić – EU aquaponics produce – consumer perceptions
Agnès Joly – Aquaponics in France – From dream to reality
Peter Chisnall from the EUREKA Secretariat gave a presentation on how SMEs can apply for funding from Eurostars-2.