An introduction into the world of farming with fish
Aquaponics is a system of agriculture that combines traditional aquaculture and hydroponics. Sylvia Bernstein’s (2011) book on the subject defines aquaponics as:
“The cultivation of fish and plants together in a constructed, recirculating ecosystem utilizing natural bacterial cycles to convert fish waste to plant nutrients. This is an environmentally friendly, natural food-growing method that harnesses the best attributes of aquaculture and hydroponics without the need to discard any water or filtrate or add chemical fertilizers.”
The Components
To better understand aquaponics and the benefits it holds as an agricultural technique you must first understand it’s components, hydroponics and aquaculture. Hydroponics is the cultivation of crops without soil, typically through the use of a nutrient rich fluid and a non soil medium such as gravel or expanded clay. The main benefits of hydroponics include the ability to grow food in non-arable regions and its ability to be used in nearly any climate through the use of greenhouses. Hydroponics systems also have downsides. There are expensive nutrients that must be mixed with water and the water must be replaced occasionally due to salinity build up. Hydroponics is also quite labor intensive. It is necessary for farmers to test the properties of their water daily to ensure the correct nutrients are being supplied to the plants.This all leads to expensive maintenance costs for a hydroponic system. The other component of aquaponics is aquaculture, or the growing of fish in a controlled environment. A recent development that has made aquaculture more efficient is known as recirculating aquaculture systems, or RAS (Bernstein, 2011). These RAS systems are man-made tanks, densely packed with fish that rely on the system's ability to draw carbon dioxide and waste from the water while also aerating it, to create an optimal environment for fish survival (Ebeling & Timmons, 2012). This method of fish cultivation has significant drawbacks when used with traditional cultivation methods, as these high-packing densities of fish require a constant source of power.If the filtration system were to shut down, many fish would die within hours from oxygen loss.
How They Work Together
When both hydroponics and aquaculture work in conjunction, they can mitigate each other's weaknesses. The fish waste that was an unnecessary byproduct in aquaculture becomes a valuable replacement for chemical nutrients in aquaponics. Aquaponics also takes notes from nature, making each system its own small ecosystem complete with animals, plants, and microbial organisms that will naturally balance the system in the way a hydroponic farmer would need to manually do each day. This greatly minimizes the amount of work required to keep the system viable. All of these positives make aquaponics a much more viable option than the cultivation techniques that make it up.
Sources
Bernstein, S. (2011). Aquaponic gardening a step-by-step guide to raising vegetables and fish together. Gabriola, B.C: New Society Pub.
Ebeling, J. M., & Timmons, M. B. (2012). Recirculating aquaculture systems Wiley-Blackwell. doi:10.1002/9781118250105.ch11