Aquaponics is a closed-loop system in food production that combines fish and vegetable growth by utilizing recycled water. As the population is projected to reach 9.7 billion by 2050, the need for sustainable and resource-efficient food production methods is critical. Wild fish stocks are declining, while farmed fish production has doubled in the past 15 years. Shifting these farms to land could potentially revolutionize food production through large-scale aquaponics operations, requiring less space, water, and energy than ever before.
Here’s how it works
Aquaponics involves pumping water from a fish tank to vegetables in a greenhouse, creating a recirculating system. The plants are placed on floating foam rafts without soil, and their roots extend into water-filled tubs. The fish excrement serves as a natural fertilizer, while the vegetables cleanse the water, establishing a mutually beneficial relationship in this method.
The crucial beneficial bacteria that break down fish waste into a form of nitrogen that plants can use to grow are the third player in the system. If they were absent, the waste would not be appropriately recycled.
The system is powered by two inputs: fish feed and energy, and both can be sustainable with proper sourcing. Salmon and other carnivorous fish typically rely on protein-based feed sourced from forage fish, but targeting these fish can pose sustainability issues. However, some fisheries are addressing this by improving their environmental impact through assessments and responsible fishing plans. To make these systems more eco-friendly, using insects as feed instead of forage fish and relying on renewable energy are effective methods. The Circle, an aquaponics venture based in Rome, has been operating since 2018 and uses solar power. Additionally, their koi fish are fed with microalgae-based feed.
Although most aquaponics systems primarily use freshwater, there has been significant progress in pioneering research on the utilization of saltwater species.
Aquaponics addresses many of the concerns found in agriculture and aquaculture
Industrial agriculture operations often rely on pesticides, herbicides, and fertilizers for controlling crops. However, these inputs come with environmental and health concerns. On the other hand, aquaponics systems are highly self-regulating and do not require any chemical additives or fertilizers. Water usage is another aspect to consider in agriculture, as the global food production alone utilizes 70% of freshwater resources. By implementing more efficient irrigation methods, around 30-70% more water can be saved. In contrast, aquaponics outperforms other methods by reducing water usage by a staggering 90%.
Fish farming raises several environmental concerns, such as the use of antibiotics, escapement of farmed fish, discharge of waste, and chemical usage. However, these concerns are eliminated in land-based aquaponics systems, where there is no possibility of farmed fish escape and no waste is produced. As per Seafood Watch, land-based recirculating systems are currently generating some of the most sustainable fish worldwide.
More people, more pollution, more need for food
Due to the continuously increasing world population, numerous challenges affecting both human health and the environment are also escalating. While raising awareness about man-made chemicals polluting our freshwater sources, many water advocates fail to mention the issue of agricultural pollution.
Per- and polyfluoroalkyl substances (PFAS) are chemicals that are increasingly causing concern due to their presence in firefighting foams, waterproofing products, and various other household items. A growing body of research has established a connection between PFAS and various health issues. Furthermore, studies have discovered the presence of PFAS even in our most isolated water sources.
In addition to industrial pollution, water pollution is also caused by traditional agricultural practices that consume significant amounts of freshwater. Furthermore, the use of fertilizers and chemicals in these practices ultimately results in their entry into our water systems.
In summary, our main goal is to discover sustainable methods to safeguard our water resources, while simultaneously nourishing our expanding population in a secure manner, particularly in regions facing food scarcity. Additionally, it is crucial to implement these solutions in areas where the soil and/or water is contaminated, thereby avoiding the pollution of crops cultivated in such conditions.
Hydroponics as an alternative approach to agriculture
Hydroponics is a method of cultivating plants without soil, making it a viable solution for growing food in regions affected by soil or water contamination. Additionally, hydroponics serves as an innovative strategy in addressing food scarcity in areas referred to as “food deserts,” which are characterized by the absence of nourishing and high-quality food options.
Hydroponics involves the use of a water-based fertilizer and mineral solution to cultivate plants without soil. The complexity of these systems can vary. At one end of the spectrum are uncomplicated deep-water culture systems, in which plants are suspended over a container containing water-based nutrients. At the other end, more advanced recirculating systems circulate nutrient-rich water through a setup that enables plants to absorb the necessary substances as the water flows past their roots. To ensure plants receive sufficient nutrients, hydroponic systems necessitate periodic water exchanges. These exchanges involve replacing the old water solutions with fresh ones.
The use of fertilizer in hydroponics is a drawback because it can have potential effects on plant and human health, as well as disposal concerns during water exchange. However, the extent of this concern depends on the type (natural vs. chemical) and amount of fertilizer used.
Fish farming: Aquaculture is a growing strategy to produce fresh fish
As our population grows, our demand for food also increases. However, the consumption and depletion of wild fish species are also on the rise. To tackle this issue, fish farming, also known as aquaculture, has emerged. It aims to meet market demands and provide locally sourced, high-quality food for certain communities. Fish farming is carried out in various methods, but two main approaches are commonly used.
- specially made tanks (think massive fish tanks)
- various cages that are suspended in lakes, oceans, rivers, and other waterways
A study conducted in Egypt demonstrated that Tilapia raised in wastewater treatment facilities can be healthy. However, other high-intensity fish farms can have negative effects on local water sources due to fish waste, excess fish food, and diseases resulting from close confinement. Additionally, certain aquaculture systems use chemicals to clean their systems, which can potentially enter nearby waterways. Furthermore, research conducted in Andhrapradesh, India revealed that aquaculture discharge into natural canals caused pollution in the well water used by nearby residents.
Aquaponics: A combination of fish farming and hydroponics
Let’s proceed by discussing aquaponics after covering hydroponics and fish-farming (aquaculture) individually. Aquaponics provides numerous benefits such as minimizing water exchanges compared to conventional hydroponic systems. This reduction creates a decline in the release of fertilizers and chemicals into waterways.
- Reduces fish waste released as pollution into waterways as the waste is used as plant food.
- Systems combine the strengths of hydroponic and aquaculture systems while also addressing their shortcomings in terms of reducing waste and conserving water.
- Offers a water use rate of less than 10 percent of available freshwater resources compared to 70 percent for global agriculture.
Aquaponics systems can be constructed in various locations including greenhouses, homes, rooftops, and rural and urban settings. The closed-loop feature of these systems minimizes water consumption and the discharge of polluted water into freshwater sources. Moreover, the system provides a conducive habitat for the fish through the natural filtration process facilitated by plants. As the availability of fertile land and freshwater diminishes in proportion to the demands of the expanding population, the necessity for innovative crops and agricultural systems increases.
What you can do
You have the opportunity to try aquaponics at home, whether you opt for a small five-gallon fish tank or a larger system with hundreds of gallons of recirculated water. This method offers an enjoyable and fascinating approach to decrease water consumption, minimize water pollution, mitigate our environmental impact, and supply our families with fresh fish and produce.
