From Wikipedia, the free encyclopedia
Aquaponics /ˈækwəˈpɒnɨks/ is the symbiotic cultivation of plants and aquatic animals in a recirculating environment.
Aquatic animal effluent (for example fish waste) accumulates in water as a by-product of keeping them in a closed system or tank (for example a recirculating aquaculture system). The effluent-rich water becomes high in plant nutrients but this is correspondingly toxic to the aquatic animal.
Plants are grown in a way (for example a hydroponic system) that enables them to utilize the nutrient-rich water. The plants take up the nutrients, reducing or eliminating the water’s toxicity for the aquatic animal.
The water, now clean, is returned to the aquatic animal environment and the cycle continues. Aquaponic systems do not discharge or exchange water. The systems rely on the relationship between the aquatic animals and the plants to maintain the environment. Water is only added to replace water loss from absorption by the plants, evaporation into the air, or the removal of biomass from the system.
Aquaponic systems vary in size from small indoor units to large commercial units. They can use fresh or salt water depending on the type of aquatic animal and vegetation.
Some consider Aztec chinampas to be the first example of aquaponics. Others refer to ancient Egypt. Either way, it is clear that aquaponics have ancient roots.
“Integrated vegetable growing and fish farming polyculture systems have long been used in Far Eastern countries such as China and Thailand. Farm wastes are commonly added as feed to fish ponds and fish are often cultured in flooded rice paddies.”
Modern Western beginnings
At the New Alchemy Institute (1971–1991) researchers experimented with bioshelters and wastewater management via crop production. This pursuit, of what was to become thepermaculture movement, inspired like-minded researchers to advance the concept of fish effluent as fertilizer for crop production.
In 1974 “The Journal of New Alchemists No.2″ was published by the New Alchemy Institute and contained an article by William McLarney “Irrigation of Garden Vegetables with Fertile Fish Pond Water”. This article was followed with “Further Experiments in the Irrigation of Garden Vegetables with Fertile Fish Pond Water” by William McLarney in 1976 in “The Journal of the New Alchemists No.3″. Still neither of these was symbiotic relationships in a circulatory environment.
Formal interest in the combining of aquaculture and hydroponics seems to have started in the mid-1970s. In 1975 K. Sneed, K. Allen and JE Ellis wrote one of the first articles about integrating fish farming and hydroponics. It would take another decade however before a greater amount of research in the integration of the two areas would start to crystallize into the true beginnings of aquaponics.
In the late 1970s Ronald D. Zweig and several other researchers published articles with the New Alchemy Institute about Fish Culture Systems and Solar-Algae Ponds. The progression of this study saw the integration of plants into the system. Ronald Zweig published “An Integrated Fish Culture Hydroponic Vegetable Production System” in the Aquaculture Magazine May/June 1986 pp34–40. It has been called “the most advanced form of aquaculture developed at New Alchemy – the Zweig hydroponic aquaculture pond – which grows both edible fish and floating hydroponic lettuce”.
In 1985, North Carolina State University (then) graduate student, Mark R. McMurtry, and professors Douglas C. Sanders, Paul V. Nelson, et al. created the first known recirculating (closed-loop), reciprocating (flood and drain) “aquaponic” system (called an Integrated Aqua-Vegeculture System) that filtered Tilapia effluent into sand biofilters (bacteria and alga) planted with Tomato and/or other vegetable crops. From the mid-1980s and throughout the 1990s both McMurtry and Sanders published a number of articles on their research and worked to develop the recirculatory techniques for the arid Third World, particularly in sub-Saharan Africa.
Aquaponics in the United States
Many institutions and enterprises followed on the efforts (replicated peer-reviewed research, active publication, dissemination and technology transfer) at North Carolina State University; notably by the University of Arizona Environmental Research Labs, NASA/CELSS, S&S Aquafarms, The Freshwater Institute, University of Arkansas (?), Bioshelters, Inc (?), Global Aquatics, Inslee Fish Farms (?) and others who carried out (mostly proprietary and unpublished) ‘research and development’ of aquaponics.
From the 1980s to present day the two distinct aquaponic systems are;
- 1 “Deep Water” or “Raft Culture” aquaponics which is the primarily research carried out at the University of the Virgin Islands under the guidance of Dr. James Rakocy and;
- 2 Reciprocating aquaponics (“Ebb and Flow” or “Flood and Drain”) based on the techniques developed by Mark McMurtry, et al. at NCSU (such as that implemented by Tom and Paula Speraneo of S&S Aquafarms in West Plains, Missouri.)
The University of the Virgin Islands Aquaculture Program has developed an aquaponic system through over 20 years of research into its design and operation. The system can produce over 10,000 lbs. of tilapia annually and a variety of vegetables that are harvested weekly in staggered production (lettuce and basil) or as needed by other fruiting crops (okra, cantaloupe, peppers, tomatoes etc.) The aquaculture program promotes several principles of aquaponics that can be applied to any size system, from hobby-scale to commercial-scale. These principles include a) system design that balances feed input to vegetable growing area, b) constant input of feed by staggering fish stocking, c) constant nutrient uptake by staggering vegetable production, d) continuous water flow and e) maintaining pH of 7.0. Other guidelines also apply and lead farmers to productive and profitable enterprises.
The University of the Virgin Islands teaches a course each June, the “International Aquaponics and Tilapia Aquaculture Course“ to participants from around the globe. These individuals return home to develop their own commercial enterprises based on the aquaponic principles taught in the course.
In 1997 Rebecca Nelson and John Pade began publishing the Aquaponics Journal [www.aquaponicsjournal.com]. The Aquaponics Journal was the first publicaiton to bring the research and various applications of aquaponics to people around the globe. Nelson and Pade also began offering training and internships at their facility in Mariposa, CA during the 1990s. In 2004 they produced the first video on aquaponics and in 2008, they wrote and published the first comprehensive book on aquaponics, “Aquaponic Food Production.” They are known throughout the industry as leaders for offering training, consulting and sytstems. Nelson and Pade work closely with Dr. Rakocy of the University of the Virgin Islands to bring the research on aquaponics into mainstream agriculture. Now located in Montello, WI, they are expanding their business and are the only full-spectrum provider of aquaponic systems, supplies, training and consulting in the US.
A graduate of the 2007 University of the Virgin Islands Short Course in Aquaponics, Tim Mann and his wife and partner Susanne started an aquaponics farm (Friendly Aquaponics, Inc) in Hawaii in 2007. This was the first aquaponics farm in the USA to have its produce USDA Organic certified and Food Safety Certified, and is currently shipping 1,600 pounds of its organic lettuce mix and 300 pounds of white tilapia per month. Friendly Aquaponics teaches the “Commercial Aquaponics Training“ twice a year to participants worldwide. Attendees have developed their own commercial and educational enterprises based on the information provided in the course.
Aquaponics Research in Canada
The first aquaponics research in Canada was a small system added onto existing aquaculture research at a research station in Lethbridge. Later, a larger set-up was built in Brooks, Alberta. Scientists, especially Dr. Nick Savidov, at this research station have made some interesting findings related to rapid root growth in aquaponics systems.
Dr. Savidov’s research is unusual for aquaponics as it is based out of a plant science background. His team took the system developed at the University of Virgin Islands and adapted it into a system in an Alberta greenhouse. One of the interesting adaptations that he made was to run his system at a low pH level (favoured by plants), rather than a system that is half-way between the ideal (low) pH for plants and neutral to high pH for fish. He found that even with a lower pH, the fish could survive nicely because of other advantages in the system over traditional aquaculture.
The Edmonton Aquaponics Society in Northern Alberta is adapting Dr. Savidov’s commercial sized system to a smaller scale prototype. Their project will optimize a sustainableconsumer system (operator is end user) to produce local food for families, small groups, or restaurants. One of the areas of research they will focus on is further development of Dr. Savidov’s innovation to close the solid waste loop. By utilizing this technology, the only loss of water from the system now is through transpiration, evaporation, and biomass growth.
The unique advantages of aquaponic systems are:
- Conservation through constant water reuse and recycling.
- Organic fertilization of plants with natural fish emulsion.
- The elimination of solid waste disposal from intensive aquaculture.
- The reduction of needed cropland to produce like crops.
- The overall reduction of environmental footprint for crop production.
- Small efficient commercial installations can be built close to markets therefore reducing food miles.
Some conceivable disadvantages with aquaponics are:
- Initial expense for housing, tank, plumbing, pump/s, and grow beds.
- The infinite number of ways in which a system can be configured lends itself to equally varying results, conflicting research, and successes or failures.
- Some Aquaponic installations rely heavily on man-made energy, technology solutions, and environmental control to achieve recirculation and water/ambient temperatures but a system designed with energy conservation in mind (such as utilizing solar heating and the exploitation of gravity to reduce pumping) can be extremely energy efficient.
- Whilst careful design can minimize the risk, Aquaponics systems can have multiple ‘single points of failure’ where problems such as an electrical failure or pipe blockage can lead to a complete loss of fish stock.
- Like all aquaculture based systems, stock feed usually consists of fish meal derived from lower value species. Ongoing depletion of wild fish stocks makes this practice unsustainable. There are now, however, organic fish feeds available which may prove to be a viable alternative and negate this concern. Other alternatives include growing duckweed with an Aquaponics system that feeds the same fish grown on the system, as well as growing Black Soldier Fly larva to feed to the fish using composting grub growers.
Aquaponic systems can be used to replicate controlled wetland conditions that are useful for reclaiming potable water from typical household sewage, in addition to generating a continual supply of food with minimal fertilizer use. Aquaponics takes advantage of synergy between self-organizing biological systems, emphasizing the one element/many functions principle of permaculture as a natural solution for water treatment.
In practice, tilapia (Most commonly nile tilapia, or Oreochromis niloticus) are the most popular fish chosen for home and commercial projects that are intended to raise edible fish. Most green leafy vegetables grow well in the hydroponic filter. Although sometimes selected minerals or nutrients such as iron are added, the main source of nutrients for the plants is the fish waste. In Australia, due to a ban on Tilapia in all states bar W.A., natives are the most popular fish, including Silver Perch, Jade Perch, Sleepy Cod, Murray cod and Barramundi. Rainbow and brown trout while not native to Australia are also in use – along with fresh water crayfish such as yabby and redclaw.