Aquaponics, derived from the words aquaculture and hydroponics, is a system which integrates hydroponic systems and aquaculture systems in a symbiotic environment. Both systems are integrated in a manner so as to mutually benefit from each other and both systems complement each other to form a single unit instead of forming separate ecosystems. The benefits and advantages of aquaponic systems are numerous and quite unique. Such systems utilize only a fraction of water required to sustain and harvest aquatic life, contain no added chemicals and only need about 10% of the water needed for proper field plant cultivation. Aquaponic gardens are self sustained systems and require only food for the aquatic life and a weekly addition of water to account for the losses due to evaporation and plant respiration. The beauty of the system lies in the fact that even in the absence of any external maintenance; the water retains its original pH levels and remains crystal clear and pristine.
In Aquaponics systems, the waste from the aquaculture system, or the fish tanks, is converted into nitrates as a result of the treatments carried out by natural bacteria. This waste, after being absorbed by the plants, is transferred to a bio filter system and the end product is a nutrient that aids in agricultural and plant growth. Because of the various benefits it provides, aquaponics systems are now widely recongised as the future for commercial fish farming and home gardening by farmers, green house operators and even home owners. The limelight garnered by aquaponics systems can be attributed to a number of reasons, some of which are given below:
1. *Aquaponics are being integrated into the training regimens of schools and vocational centers which are designed around studying bio-systems
2. Hyrdoponics are widely considered by fish farmers as an excellent bio-filtration source which helps in intensifying the growth of fish and aquatic animals in the aquaculture system.
3. Aquaponics are also highly beneficial for greenhouse operators. Such systems provide greenhouse growers with an excellent method of introducing organic water based produce to the market without incurring any additional costs. This is because the nutrients required for the growth of the plants are provided by the aquaculture system and the only thing which needs to be purchased is fish food.
4. The fish waste present in water origination from hydroponic systems is widely regarded as an organic fertilizer which can be utilized for plant growth.
5. These systems provide a viable, eco friendly and green solution for obtaining two sources of food from a single system
6. Since the water in aquaponics system is recycled and re used, they provide an excellent solution for providing fresh vegetables and fruit in arid areas where there is a scarcity of water and fertile earth.
7. The symbiotic environment of these systems provides a sustainable eco system, in which both plant and fish mutually benefit from each other. As a result, aquaponics can be used as a source for a steady supply of food products.
The various facets of general aquaponic systems are given below:
Characteristics of Water in Aquaponic Gardens:
In order to maintain the working the system, it is imperative that the quality and characteristics of the water be checked thoroughly and diligently. The quality of the water in the re-circulating tank has a great impact on the survival and growth of the fish. Parameters such as the levels of oxygen, ammonia, nitrates, pH, nitrites, chlorine and various other characteristics have to be monitored carefully. These factors can fluctuate because of a number of reasons and have an overall adverse effect. The growth rate of fish, density and feeding rate can also cause rapid and sudden changes in the quality of the water.
Plants for Aquaponic Gardens:
The type and number of plants that are used in aquaponics is dependent upon a number of factors. Aspects like the density of aquatic life in the fish tank and the subsequent concentration of nutrients present in the water are the two major factors that dictate the types of plants that can be cultivated in the system. Plants and vegetables which generally require a lower amount of nutrients, like lettuce, cabbage, spinach and chives, are highly suitable for these systems. In essence, the greater the fish stock in the tank, the greater will the concentration of water based nutrients enabling farmers to integrate a wide variety of plants and vegetables into the system.
The effluent from the fish tank, which contains mainly ammonia and suspended solids, is passed through a series of cartridges and filters which are part of the bio-filteration system. The aim of this system is to convert the waste materials into nutrients which are then absorbed by the plant life and facilitate their growth. A variation of this system involves a gravel bed to which all the waste materials are directed. The gravel is used to remove the solid suspended particles and also fosters bacteria which convert the ammonia into nitrates. This type of a system is known as a gravel-cultured hydroponic.
Fish Species for Aquaponic Gardens:
The types and species of fish that can be adapted to such systems is quite varied, and includes both warm-water and cold-water fish. Re-circulating aquaculture systems integrate a number of fish species like the trout, char, bass and the tilapia amongst others. The Barramundi and Murray cod fish are also adopted in aquaponics in Australia. However, the most common fish that is adapted to aquaculture systems is the tilapia, and this is because of the species’ high tolerance to changes in the water oxygen levels, pH levels and temperature changes. The tilapia also provides an excellent source of food, and is a common sight in fish markets. Most commercial systems use the tilapia in their aquaponic systems.
Ratio between the Two Systems:
The ratio between the size and volume of the two tanks (plant and fish) is generally referred to as the component ratio of an Aquaponic system. The ratio of the components is mainly dictated by the particular use of the system and fish tank and plant beds generally have a ratio of 1:1. However, current systems generally employ ratios of the order of 1:2 and even as high as 1:4. The component ratio can be varied in such a way so as to attain a greater output from either of the two integrated systems and provides a degree of customization and flexibility to its users.