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500 BC, China
The first written record of aquaponic methods was published by Fan Lai in China in 500 BC.

1000 AD, Americas
Mayan and Aztec cultures developed aquaponic methods before 1000 AD. They created artificial planted rafts called chinampas in lakes and ponds, with plant roots extending into the water below the surface. The ancient Aztec capital Tenochtitlan was established in the middle of a large, shallow lake, and by some estimates crops such as corn, beans, squash, peppers and tomatoes grown on chinampas may have provided one-half or more of the city’s food supplies.

1150-1350 AD, Central America
The concept of using fish excrement to fertilize plants has existed for millennia, with early civilizations in both Asia and South America using this method. The most well-known examples are the ‘stationary islands’ or Aztec chinampas set up in shallow lakes in central America (1150–1350 BC), and the rice-fish aquaculture system introduced in Asia about 1500 years ago, and still used today. Both the rice-fish aquaculture system and the chinampas were listed by the FAO as Globally Important Agricultural Heritage Systems (Koohafkan & Altieri 2018).

There has been much dispute about the origin story of the aquaponics system; however, many records trace the pilot forms of the systems back to the days of the medieval Aztecs inhabiting inner Mexico in 1000 AD (Shabeer, 2016). These Aztecs were said to have developed the first version of the aquaponics production system because they did not have sufficient land to grow their food. In their “archaic” approach to solving this land problem, they constructed rafts that were covered with soil to enable the planting of vegetable crops. These were termed “floating farms” and represented the earliest forms of aquaponics systems designed to produce food (Jones, 2002). However, up till this point, the production system seemed to be descriptive of a simple soil-less culture rather than an aquaponic system. The introduction of fish into the established system described above could be linked to farmers in South China and Thailand who cultured suitable fish species alongside rice in paddy fields (Shabeer, 2016). Another variant would be the Chinese farmers rearing ducks in cages located above rearing tanks of fin fishes. Hence, the duck's fecal droppings were used to feed the fish, while the feces of the fish and wastewater were transferred into a catfish tank and subsequently into the rice crops (Rakocy et al., 2004).

An integrated system of aquaculture and agriculture where fish are grown in rice paddies has been employed in the North Kerian area of Perak in Peninsular Malaysia since the 1930's. 18 Such an integrated rice paddy-fish farming system is practiced extensively in the North Kerian area of Perak in Peninsular Malaysia. 19 Several rice-fish systems are also reported to have a long history in Indonesia. These include the minapadi, penyelang, and palawga in West Java and sawah tambak in coastal East Java, which employs a brackish water-freshwater system containing prawns, fish and rice.

1519: The Chinampas of the Aztec
The lake-borne city Tenochtitlan was estimated to occupy around 3–350,000 inhabitants. Originating in the Valley of Mexico during the Aztec period, chinampas were constructed as networks of raised fields on man-made islands within marshy areas and shallow lakes. The construction involved layering lakebed clays, mud, aquatic plant matter, crop residues, silt, and manures within reed fences anchored at the lake or marsh bottom. Once elevated to the desired height, willow trees were planted along the perimeters to prevent erosion, offer shade, and serve as a barrier against pests. Chinampas typically measured between 5 and 10 meters in width and could extend up to 90 meters in length, with a height approximately 0.5 meters above the water surface. The spaces between the chinampa beds, canals approximately 1 to 1.3 meters wide, facilitated not only a diverse ecosystem of wildlife and fish but also served as efficient waterways for canoes transporting labor and resources.This method of agriculture leveraged the ecological benefits of combining aquatic and terrestrial farming, playing a crucial role in supporting the dense population of the Valley of Mexico during the Aztec era.

The Chinese Dike-Pond System
In the Pearl Delta of south China, a land-water farming system, also known as the dike-pond system, evolved during the mid-fourteenth century. The dike-pond system evolved as an important flood control measure in the delta. Water control measures were started in the lower-lying areas, where small watercourses were dammed and created to make fishponds. Ponds were dug to drain the marshes and natural ponds in order to create agricultural land, and the excavated was used to construct dykes. The fishponds were stocked with carp fry naturally occurring in the delta (Ruddle and Zhong 1988). The first commercial crops to be grown on the dikes were Litchi and Longan followed later on by mulberry. The mulberry leaves provided an important feed for the cash crop: silkworms. Silkworm excrement was thrown into the pond, and 6 Aquaponics: A Commercial Niche for Sustainable Modern Aquaculture 175 accidentally gave way to the discovery that it could feed the fish. The mud at the bottom of the ponds was used to fertilize trees, when there was a shortage of animal manure. The pond is drained two or three times a year, and mud at the bottom is retrieved up on the dikes, which then are repaired while the depth of the pond is restored. Livestock are also part of a dike-pond system. Both small and large animals like pigs or ducks can be bred on the dykes and their manure can be thrown into the pond and thus promote growth of algae which the carp can feed on. Through photosynthesis the algae in the pond give off oxygen and produce glucose, added nutrients that benefit both fish and aquatic plants. Fish fodder may also be cultivated on the dykes, for example Miscanthus, or fodder for animals that live on the dikes.

Modern Aquaponics
In the late 70s and early 80s, researchers at the New Alchemy Institute North Carolina State University (USA) developed the basis of modern aquaponics.

1969 - 1991: The New Alchemists
In 1969, William McLarney, Nancy, and John Todd built a prototype replica of the Aztec's aquaponic system (with some modifications) to provide shelter, vegetables, and fish throughout the year (Shabeer, 2016). The numerous records of developmental attempts in the history of aquaponic production systems all have led to the current level of efficiency and systems prototype we have today.

In 1969, John and Nancy Todd and William McLarney founded the New Alchemy Institute.1 The culmination of their efforts was the construction of a prototype Bioshelter, the “Ark”. The Ark was a solar-powered, self-sufficient, bio-shelter designed to accommodate the year-round needs of a family of four using holistic methods to provide fish, vegetables and shelter (Bradley 2014).

The New Alchemy Institute in East Falmouth, Massachusetts, conducted research on integrated aquaculture systems during the 1970s and the 1980s. Although the institute closed in 1991, New Alchemy publications on greenhouse production and aquaponics provide historical insight to the emerging bioshelter (ecosystem greenhouses) concept and are still a valuable resource for technical information. The Green Center, formed by a group of former New Alchemists, is again making these publications available for sale. h e website has a section featuring for-sale articles on aquaculture and bioshelters (integrated systems). A selection of past articles is available online.

In 1989, Ron Zweig from the New Alchemists and Dr. Mark McMurtry co-taught a course on integrated aquaculture at Woods Hole Oceanographic Institute. (source - personal communication)[citation needed].

1980s: Dr. Mark McMurtry
During the mid-1980s, Mark McMurtry and Professor Doug Sanders at North Carolina State University developed an aqua-vegeculture system based on Tilapia fish tanks sunken below the greenhouse floor. Effluent from the fish tanks was trickle-irrigated onto sand-cultured hydroponic vegetable beds located at ground level. The nutrients in the irrigation water fed tomato and cucumber crops, and the plants and sand beds served as a bio-filter. After draining from the beds, the water recirculated back into the fish tanks. The only fertility input to the system was fish feed (32% protein) (Diver 2000).

Bioshelters in Amhurst
The first larger scale commercial aquaponics facility, Bioshelters in Amherst, MA, was established in the mid-1980s.

1990s: Tom and Paula Speraneo
in the early 1990s, Missouri farmers Tom and Paula Speraneo inspired by Mark McMurtry, introduced their Bioponics concept. They grew herbs and vegetables in ‘ebb and flow gravel grow beds’ irrigated by the nutrient rich water from a 2200 L tank in which they raised Tilapia (Bradley 2014). While gravel grow beds had been used for decades by hydroponics growers, the Speraneos were the first to make effective use of them in Aquaponics—remembering prior to this, sand was the main growing medium used in emerging aquaponics systems. Their system was practical and has been widely duplicated, and many present day DIY (Do-It-Yourself) aquaponics owes its origin to the Speraneos. They wrote a ‘how-to manual’ that became a springboard for many home based or school educational systems built throughout the world. However, the Speraneos system of substituting sand for gravel in ebb and flow beds only works well if the system is fitted with dedicated mechanical and biological filtration. If not, the system will bear the risk of an eventual ‘collapse’, due to the accumulation of organic matter using up oxygen in the system needed for the fish and furthermore reduced aeration of media bacteria and the plant root zone.

1997: DWC
By 1997, Rakocy and his colleagues developed the use of deep-water culture hydroponic grow beds in a large-scale aquaponics system. The system developed at UVI is a raft hydroponic system and the aquaculture part focus is on Tilapia production (Rakocy et al. 1997, 2007). The system (Fig. 6.2) was based on four fish rearing tanks, each with 7.8 m3 water volume (total 31.2 m3 ), two cylindro-conical clarifiers (3.8 m3 each), four rectangular filter tanks (0.7 m3 each) containing orchard netting, six hydroponic tanks (11.5 m3 each) and a sump (0.6 m3 ). The hydroponic tanks were 30.5 m long by 1.2 m wide by 0.4 m deep and had a combined surface area of 214 m2. Thus, the surface area to fish tank volume was 6.85 m2 /m3. The water volume was 110 m3. A 0.5 hp in-line pump moved water at an average rate of 378 L/min from the sump to the fish rearing tanks (mean retention time of water 1.5 h), from which effluent flowed with gravity through the system. Air diffusers were used both in fish and hydroponic tanks through air stones supplied by air from a 1.5 hp blower for fish and 1 hp blower for plants (Rakocy et al. 2007). The daily fish feed input averaged 12 kg equivalent to 56 g/m2 plant growing area. The waste water from the fish was only supplemented with potassium (K), calcium (Ca) and iron (Fe) to provide sufficient amounts of the essential nutrients for normal plant growth.

Organic Certification
Organic certification appears to be a natural step for an aquaponics producer since the whole system is based on a holistic thinking in terms of recycling, lowering the resource intake and securing zero pollution. However, the present organic regulatory regime does not have any standards or regulations for certifying organic aquaponics. The RAS technology is even forbidden under the present organic regulation, which seems to be more of an economic protection to the extensive open pond systems prevalent in organic fish production rather than having anything to do with fish welfare or the aquatic environment. It is only possible to have an aquaponics production system completely certified organic if a non-holistic approach is made, meaning a certification towards the organic fish- and horticulture regulation is made separately. Firstly, the plants must be grown in soil. Secondly, the fish produced must be fed with organic certified fish feed, and thirdly the fish can only be produced in a RAS system if the fish are sold as fingerlings for further growth in open-air pond systems certified organic. However, if aquaponic produce gains markets and moves into larger scale production systems, it seems indisputably; that the organic farm movement will need to revise its present regulation focusing on specific technologies rather than having a more principle based approach allowing for new resource productive and holistic production systems such as aquaponics. The present regulatory framework for organic fish and horticultural production in the EU is regulated by the Council Regulation (EC) No. 834/2007 whereas more detailed rules are regulated by the Commission Regulations (EC) No. 889/2008, and (EC) no. 710/2009. The crux for aquaponics producers to get an organic certification in the future lies in the acceptance of the recirculating technology within organic regulation itself, as well as presenting aquaponics as an ideal closed loop, non-pollute and holistic food production system.

Utilization of Solids
In current recirculating aquaculture systems and aquaponics setups, 30–65% of the phosphorus added to the system via fish feed is lost in the form of fish sludge that is filtered out by mechanical filtration. Since phosphorus is a major component of agricultural fertilizer, the development of phosphorus recycling production systems in aquaponics would be an important contribution for future food production.

Under current practices in RAS, the solid wastes are only partially solubilized as they are mechanically filtered out on a daily basis [57].

Phosphorus
In RAS, 30%–65% of the phosphorus added to the system via fish feed is lost in the form of fish solid excretion that is filtered out by either settling tanks or mechanical filters [25,79]. Moreover, organic P solubilized as orthophosphate can precipitate with calcium (e.g., hydroxyapatite–Ca5(PO4)3(OH)) making these elements less available in solution. As up to 65% of P can be wasted in form of aquaculture effluent sludge, recovery solutions should be developed to achieve zero-discharge systems. For example, leachate rich in P could be obtained by sludge digestion with selected P-solubilizing microorganisms [58] and then reinserted in the hydroponic part of the system. The ultimate objective is to develop a zero-discharge recirculating system with maximum nutrient recycling transformed into plant biomass and improved yield.

Feeding Rates
Rakocy reports a value between 60 and 100 g day−1 m−2 has been recommended for leafy-greens growing on raft hydroponic systems. Endut et al. [31] found an optimum ratio of 15–42 grams of fish feed day.

Dr. Mark McMurtry suggests a feed rate per/m2 of filter in the 25 to 30 g/day range (until determined either excessive/insufficient).

Pest and Disease Management
Conventional pesticides that are used in hydroponics cannot be used in aquaponics because of toxicity risk to the fish and to the desired biofilm (e.g., autotrophic nitrifying biofilm). The need to maintain the nitrification biofilm and other nutrient solubilizing microorganisms also prevents the use of antibiotics and fungicides for fish pathogen control and removal in the aquatic environment. Furthermore, antibiotics are not allowed for plant application so their use against fish pathogens must be avoided in aquaponic systems. Microbial diversity can be beneficial for plants. The presence of some mutualistic microorganisms in the plant biosphere can retard the development of pathogens [34,89,90] while promoting growth (e.g., plant growth-promoting rhizobacteria and plant growth-promoting fungi).

Food Safety
Since the presence of a broad range microflora belongs to aquaponic practices, the occurrence of pathogens and risk for human health should also be established, in order to assess the safety of aquaponics and to conduct appropriate quality control. These challenges can lead to the production of products that are quality and pesticide free certified (e.g., organic) and thereby achieve a higher prize in the market and leads to a healthier population [91].