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Aquaponics, What It Is and How It Works

What is aquaponics, how it works, its advantages and disadvantages? And most importantly, is it a sustainable and organic cultivation method or not?

by BioGrow

Have you ever heard of aquaculture or, more specifically, aquaponics? For many, the term is obscure, but the concept is rather simple. Essentially, it’s a particular water-based cultivation technique carving out its space in the agricultural world. But what exactly is aquaponics? What does it involve, how does it work, what are its advantages and disadvantages? And above all, is it a sustainable and organic type of cultivation or not?

To get a clearer picture of this particular form of agriculture, we turned to Andrea Alberto Forchino, a biologist specializing in aquaculture. Andrea is currently a researcher at the Department of Environmental Sciences, Informatics, and Statistics at “Ca’ Foscari” University in Venice.

Sustainable Agriculture: Aquaponics

by Andrea Alberto Forchino
Given climate change and the international economic crisis, it’s evident that the agri-food sector needs to identify new strategies to ensure more sustainable productions in line with new market needs. Breeders and agricultural producers are indeed facing challenges arising from climate change and its effects on the environment, biodiversity, and living conditions. The water scarcity that has affected Italian regions in recent years has severely tested farmers and fish farmers who have seen their productions diminish or suffer significant damage (just think of the fish mortality in the Orbetello lagoon in 2015 or, more recently, the 20 tons of dead trout in Friuli in the Ente Tutela Pesca breeding). In this context, aquaponics could represent a concrete possibility for the development of this sector. But what is aquaponics and how does it work?

What Is Aquaponics?

Aquaponics cycle

Aquaponics cycle

Aquaponics can be defined as the union between aquaculture and hydroponic cultivation. The latter is a practice in which plants are grown without soil, solely using water enriched with all the necessary nutrients for the plants. In the case of aquaponics, the essential nutrients for plant growth are provided by the breeding of fish, whose waste products constitute the main source. In this system, elements like nitrogen and phosphorus, derived from both fish excretions and the decomposition of uneaten feed, can be absorbed by the roots of the cultivated plants that are directly immersed in the water. Aquaponics isn’t a new cultivation technique; substantial discussions about this technique began in the ’70s. However, it’s only in recent years that it has returned to prominence, partly due to new scientific research and increased attention to sustainability from both consumers and producers.

How Does Aquaponics Work?

An aquaponic system is a recirculating system where water, thanks to the use of one or more pumps, is taken from the tank where the fish are raised and passed through a biofilter. This biofilter initiates the nitrification process, leading to the formation of nitrites and nitrates that are then assimilated by the plants. Moreover, it reduces the amount of suspended solids as much as possible, a crucial operation to maintain good water quality and avoid a decrease in dissolved oxygen. The water is then introduced into the cultivation beds where the cultivated plants (whose roots are in direct contact with the water) are located and finally returned to the breeding tank. There are multiple plant varieties that can be cultivated, not just leafy vegetables but also plants like zucchinis, eggplants, tomatoes, or herbs. Similarly, almost all freshwater fish species can be raised in aquaponics, from trouts to carps (including ornamental species like Koi carps) or even exotic species like tilapia. It’s also possible to raise various crustacean species such as the river crayfish Austropotamobius pallipes. Depending on the chosen animal and plant species, the system needs to be calibrated to ensure the correct nutrient supply to the plants.

Schema of aquaponics system

Schema of aquaponics system

Why Is Aquaponics Sustainable?

Aquaponics can be seen as a sustainable agricultural production activity in which the cycles of the main macronutrients are closed thanks to the integration of two production systems: aquaculture and hydroponic cultivation. Compared to conventional farming techniques, aquaponics has several strengths, including:

  • Water savings: Aquaponics uses about 90% less water than traditional agriculture
  • Compact spaces: As plants don’t need soil, aquaponics allows for intensive crops in relatively limited spaces
  • No use of pesticides and phytosanitary products: Aquaponics doesn’t require their use. To avoid toxicity problems for fish and plants, biological control is used to manage potential pests. Also, efforts are made to isolate the production system from the surrounding environment to limit the entry of harmful insects and pathogens
  • No use of fertilizers: The nutrients for the plants come from fish farming
  • Emission control: No need for the use of agricultural machinery, resulting in less fossil fuel consumption.

What Are the Limits of Aquaponics?

The main limitations of aquaponics concern two fundamental aspects: the complexity of the production system and its economic sustainability. Being an integrated production system, aquaponics requires skills from the farmer/breeder concerning both plant and fish species cultivation. Economically, aquaponics can generate dual profits for practitioners by introducing two different types of products (plants and fish) into the market. However, the need to allocate these systems inside greenhouses or protected structures and condition the temperature to ensure constant year-round production increases production costs. But at the moment, this is the price consumers have to get used to paying for a genuinely sustainable product.

Is Aquaponics an Organic Farming Technique?

Just a few months ago, aquaponics in America became part of organic production techniques. In contrast, in Europe and therefore in Italy, there’s currently a regulatory gap concerning aquaponics, and therefore, although sharing all the principles of organic production, an aquaponic product can’t boast the “organic” label. However, this regulatory gap will probably be filled soon, given the enormous interest that the European Union has shown towards this agricultural technique, as evidenced by the funding and promotion of numerous projects in this regard.

Is Aquaponics Popular in Italy?

In recent years, large production facilities have been built in countries like the United States, Australia, and New Zealand, and aquaponic practices are attracting the interest of universities and companies worldwide. At the European level, the first truly productive aquaponic realities have emerged in recent years in the Netherlands (e.g., UF002), England (e.g., Bioaqua Farm, Growup Urban Farm), and Iceland (e.g., Akur Farm). In contrast, in Italy, only a few small experimental facilities have been built so far, although it is reasonable to think that significant investments will be made in this field nationally in the near future.

The Bluegrass Project

Interest in aquaponics is also evidenced by European and national funding for some projects in the field of aquaponics, including the Bluegrass project. This project started in October 2017 and is coordinated by the Department of Environmental Sciences, Informatics, and Statistics (DAIS) of Ca’ Foscari University in Venice. It lasts for 30 months and is funded within the Interreg V-A Italy-Slovenia 2014-2020 Program, aiming to promote and support the development of aquaponics in the program-covered area (Veneto, Friuli Venezia Giulia, and part of the Slovenian territory) through four main activities:

  1. Market analysis aimed at identifying specific territorial needs in terms of demand;
  2. Building 2 aquaponics pilot plants (one in Slovenia and one in Italy) where educational, demonstrative, and promotional activities involving schools and city markets will be carried out;
  3. Involvement of stakeholders, including farmers, breeders, and researchers;
  4. Promotion of communication activities aimed at raising consumer awareness.
    For this purpose, a consortium of 5 members has been created, including two universities (Ca’ Foscari, IT, and Lubiana, SLO), a public administration (UTI del Noncello, IT), and two cooperatives with expertise in aquaculture (SHORELINE, IT) and agriculture (KZ- AGRARIA, SLO)

Andrea Alberto Forchino is a biologist specializing in aquaculture. He works as a research fellow at Ca’ Foscari University in Venice in the Department of Environmental Sciences, Informatics, and Statistics. His activity is focused on the environmental sustainability of aquaculture products, including those derived from aquaponics. His recent publications in scientific journals have focused on applying Life Cycle Assessment (LCA) to this productive sector.

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