Spencer Dixon
Aquaponics: The Future of Farming

When one thinks of food production the first thing that comes to mind is the typical American farm. You envision endless fields of corn, massive tractors, and the guy in the overalls wearing the straw hat. Unfortunately modern day farms have become nothing more than chemical factories producing food. They are dependent on pouring massive amounts of fertilizers onto their fields in order to meet quotas and make a profit. These practices are destroying our environment, wasting gallons and gallons of water, and have even proven to adversely affect public health of local residents. (Factory Farming, 1) In order to solve these problems, as a nation, we must change the way we farm. The analysis of the history and evolution of aquaponics will allow society to encourage a new form of farming and solve our agricultural dilemmas. By transforming hydroponic operations into aquaponic operations, increasing the amount of urban farming thus minimizing the distance food needs to travel, and decreasing the use of water compared to conventional farming, aquaponics will create a food production for the future which is both economical and ecologically sound. The benefits of this relatively new science are vast.

The farms, better described as chemical factories, use approximately 3/4 of our world’s fresh water to feed plants. (Jones, 15) After feeding, the excess water rapidly drains into the environment. As the water drains it picks up numerous fertilizers and chemical nutrients that the farmers used to feed their plants. Surprisingly, only 10% of chemical fertilizers put on the plants are used. Thus 90% of the farmer’s costly fertilizers are left to pollute the environment. The damage this polluted run off causes is enormous. As the run off flows, a good portion gets leached into the ground water (our drinking water) and the remaining water makes its ways into the rivers and bays. When this water reaches the rivers and bays it creates an explosive growth of algae due to the high availability of nutrients. Sadly, as the algae growth booms it negatively affects the local ecosystems and even destroys aquatic life. (Scott Jones, Aquaponic Journal, Issue 24, 15)

Due to its recyclable qualities and copious benefits scientists have been moving toward aquaponics thus trying to solve the problems created by the farming agriculture. Aquaponics originates in Mother Nature in the form of aquatic eco systems. For example, bodies of water are aquatic eco systems because the fish produce waste and then the plants and algae growing in the water filter out the harmful ammonia so the fish can survive. Besides Mother Nature, the first known use of aquaponics by man dates back 1500 years ago in China. (Jones, 14) A local farmer became tired of hauling large loads of feed to his finfish, catfish, and ducks so he searched for a solution. His solution was to put the caged ducks above the finfish, as he fed the ducks the extra food and droppings would fall down for the finfish to eat. The finfish would then process the food. The processed food and any extra duck feed would then float down stream and sink to the bottom. Catfish, who are natural bottom feeders and scavengers, would then eat the food from the finfish. As the catfish processed their food, any nutrients left in the water was then channeled into the fields feeding the rice crop. Essentially the farmer only had one input (duck feed) and was able to achieve four harvests from that. And thus aquaponics was born. (Jones, 14)

As time progressed aquaponics grew from babyhood into adolescence. Two major problems that needed solving allowed aquaponics to grow into what it is today. For the aquaculturist the problem was removal of fish waste and for the hydroponic grower it was to eliminate cost of nutrients. Before Dr. Wilson Lennard became a renowned aquaponic specialist he researched the science as someone experienced in aquaculture. Dr. Lennard was looking for a way to solve the problem of Recirculating Aquaculture Systems (RAS). In RAS systems there is an extremely high density of fish in minimal space. When thousands of pounds of fish are in a very small area a lot of fish waste is produced. Removing solid waste never poses a problem but approximately 70% of the fish waste is water bound (dissolved in water). This leads to a build up of ammonia excreted from the fish’s gills. High ammonia levels create a fatal environment for fish. The only way to keep those ammonia levels down is to remove 10% of the RAS water daily. Even with a relatively small system of 100,000 liters, 10,000 liters of water must be removed daily, disposed of in an environmentally friendly way, and then restocked with another fresh 10,000 liters. Regardless of how efficient these RAS systems are at breeding fish, the cost of operation soon became a huge problem and profit was not maximized. (Steven Carruthers, 83). On the other side of the equation is the hydroponic grower. Hydroponics was proven to be an extremely successful means of growing produce. Not only do the plants grow faster than in soil but they yield more as well. (Keith Roberto, 10) In addition to faster and bigger growth, hydroponics also allowed farmers to put plants closer together since nutrients were no longer dependent on the soil. In hydroponics your main cost is nutrients and salts. Even with all the benefits of hydroponics, the soaring costs of chemical nutrients and salts make this form of growing rather expensive. It soon became obvious that these two systems needed to be integrated. The fish farmers have excess fish waste (nutrients) and the hydroponic farmers were looking for a cheaper way to feed their plants. As soon as the two sciences (aquaculture and hydroponics) started to grow in popularity farmers found aquaponics was the solution to their problems. By combining the two sciences, the aquaculturist can now breed thousands of fish and use plants as filters to keep the fish alive. On top of solving the problem for aquaculturists, aquaponics also enables multiple means of profit from just one food source (fish food).

It is important to understand how aquaponics works scientifically. There are three essential parts in an aquaponic system: fish, plants, and bacteria. All three are required in order for the system to function properly and create a mini sustainable ecosystem. As the fish eat food and swim around they produce waste. Some waste is dissolved directly into the water as nitrogen and the other waste is excreted from the fish gills in the form of ammonia. (Timmons, 768) Ammonia is toxic to the fish in high quantities so as ammonia levels start to increase, a form of bacteria called Nitrosomonas sp starts colonizing on surfaces such as gravel, sand, hydroton (clay pellets), or any other hydroponic medium. The bacteria (Nitrosomonas sp) then converts the ammonia into nitrite. Nitrite is not nearly as toxic as ammonia to the fish but doesn’t allow the fish to uptake oxygen. As the nitrite levels increase, a similar process to the one before occurs. A new bacteria, called Nitrobacter sp, starts colonizing in the system. Nitrobacter sp then converts the nitrites into nitrates. Luckily for the plants nitrate happens to be one of their favorite foods, and the fish can withstand much higher quantities of nitrate then nitrite or ammonia. Without an established bacteria colony the ecosystem will be unable to function and the fish will die if ammonia levels get too high. An original spike in ammonia is to be expected when starting a new system. As soon as that spike in ammonia is present, production of the useful bacteria will occur. The bacteria double every 15-20 hours (relatively slow for bacteria); high oxygen levels and temperatures around 20º C are ideal for bacteria growth. Establishing sufficient bacteria generally takes about four weeks. (Backyard Aquaponics Journal, 6) But the longer a system has been running the more efficient it will become. Anywhere between one and two years is when most systems will reach maximum efficiency. Any fish feed that is not consumed by the fish will then breakdown in the system adding even more dissolved nutrients to the water and allowing ammonia to convert into nitrates.

The plants, fish, and bacteria are actually part of a symbiotic relationship. More specifically they create a mutualistic relationship in which all three are benefited with increased survivorship. The plants uptake the converted nitrate and any other nutrients dissolved in the water through their root systems. By using the nutrients in the water for growth, the plants actually clean the water so nitrate levels stay manageable for the fish to live in. The fish, plants, and bacteria can all be found in nature but they are not necessarily found in the same ecosystem. So even though a certain type of fish didn’t evolve in the same ecosystem as a certain strain of basil they can still be compatible. The deciding factors of whether or not the plants and fish will be compatible are water temperature, air temperature, and pH. (Nelson, issue 33, 22) Contrary to hydroponic systems, aquaponic systems require a potassium and calcium-based buffer system to increase the pH. When the fish eat and metabolise their food it reduces the pH, so the salt buffers are added to keep the pH as close to 7 as possible and provide the plants with nutrients not found in the fish feed. In addition to the buffers, a weekly addition of chelated iron is necessary in aquaponic systems. Chelated iron is not present in fish feed but is essential in the production of chlorophyll. (Steven Carruthers, 83) Chlorophyll is necessary for healthy plant growth because it allows the plants to perform photosynthesis. If plants start turning yellow it is usually due to a lack of chelated iron.

Leading the research in aquaponics are Jim Rakocy at University of Virgin Islands, Wilson Lennard in Australia, and Nik Savidov in Canada. Jim Rakocy, the founding father in aquaponic research, was actually one of Dr. Lennards thesis examiners for his PhD in aquaponics. In 2004 Dr. Lennard was introduced to Nik Savidov in Canada who has been doing work with organic hydroponics for over twenty years, but more recently started focusing on aquaponics. The three have become great friends and share experiences and data on a regular basis. (Lennard, 2)

As fresh water started becoming a scarce resource in Australia scientists needed to find a new form of farming to maximize water use. Aquaponics proved to be the perfect solution to this problem. Research has proven that hydroponics uses roughly 1/10 of the water compared to conventional farming. (Backyard Aquaponics, 1) Due to the recirculating nature of aquaponics the only water loss is from evaporation and transpiration of plants and beds thus making aquaponics even more water efficient than hydroponics. (Brown,10) Dr. Lennard applied for a grant to start his research but was declined and offered a PhD scholarship instead. After accepting a decrease in income, in order to be able to start his research, he approached his old university (Royal Melbourne Institute of Technology (RMIT) University, in Melbourne, Australia) about offering a PhD in this field. They gladly accepted his proposal since he was already funded. (Lennard, 2) His research involved trying to optimize aquaponics for commercial use in terms of maximum plant growth and nutrient removal for Murray Cod (Australian fish). Lennard was successful and able to prove “that an optimal balance of fish to plants may be achieved, so that the same water may be used perpetually within the system.” (aquaponic.com, background). Lennard then developed a unique aquaponic design and management technique called Symbioponics. Symbioponics uses mathematical models to predict fish to plant ratios in systems. Using Symbioponics Wilson was able to conclude that under ideal conditions aquaponics “is the most water efficient food growing technology in the world today. In addition, aquaponics has zero environmental impacts (because of the absence of nutrient-rich waste-water discharges from the system) if managed correctly.” (aquaponic.com, background)

Currently, Dr. Lennard is researching a system in New Zealand that has a hydroponic and aquaponic system set up side by side in the same greenhouse. The goal is to compare the growth and quality of plants in the two systems. So far, the aquaponic system has proven to produce bigger plants of better quality. At one point, an influx of dirty river water entered both systems. This new water introduced a plant pathogen called Pythium spp, which wreaked havoc in the hydroponic system, affecting growth and causing the plants to die. Sprays and additives were required to get rid of the pathogen in this system. Aquaponic farmers are unable to use sprays and additives because it can be fatal to the fish, fortunately there was no need because the disease rate in the aquaponic system was virtually zero. This experiment showed that due to unknown biological approaches aquaponics uses, another advantage over hydroponics is disease resistance. (Lennard, 6)

Another topic Dr. Lennard is researching is designing a fish food that is produced completely from waste plant materials and Duckweed species grown on wastewater ponds. Eliminating the need for fish feed will enable aquaponics to “close the loop”, biologically speaking, so all that is required is plant waste products to run these aquaponic systems. One of Lennards’s passions is to “design and produce low-tech aquaponic systems to assist developing world peoples to grow protein and veggies for themselves”. (Lennard, 6) He hopes to go to India and construct these low-tech, water and nutrient efficient systems in Indian villages to help people survive. Dr. Lennard is even being included on a vertical farm project. The goal of the project is to build a six-story building to use for food production, with aquaponics being the major growing technology used.

His last project involves a hypothesis he has been working on for almost ten years now. Dr. Lennard plans on building his very own commercial aquaponic system, operated independently, which will demonstrate to people how to use aquaponics successfully as a business. Using Symbioponics and other design methods and managements he developed, Dr. Lennard hopes to optimize the number of fish required for greatest plant growth. The goal being to have as few fish as possible without diminishing plant production. The reason for this is because the majority of profit is in plant production and the primary costs are in fish care, feed, and setting up fish system components (tanks). By decreasing the number of fish by half compared to the average commercial system he hopes to minimize initial capitol expense and maximize profit to create a more economically viable business. (Lennard, 6)

Jim Rakocy’s interest in aquaculture started at the young age of 12 when he had 17 aquariums set up in his basement. Rakocy would breed fish and sell them to the local pet stores. Len Pampel, a colleague of Jims father, was doing work at the Milwaukee county zoo developing methods for treating water with plants and offered to help young Jim integrate the technology into his tanks for breeding fish. Rakocy later went on to get his degree in Zoology at the University of Wisconsin. After school he joined the peace corp from 1967 to 1969. Upon returning he started teaching at a Junior High School in New York for two years until he decided to go to graduate school at the University of North Carolina. At UNC Rakocy took classes involving water treatment, water chemistry, and environmental biology. One day Rakocy read an article in an aquaculture magazine about the Recirculating Aquaculture Systems (RAS) at Auburn University where they were breeding tilapia. He immediately enrolled in their program and began his studies with RAS systems. Using his knowledge from Len Pampel, Rakocy designed an extremely complex system that integrated plants to help with the water treatment. Rakocy used many different species of water plants to help with the ammonia removal. Auburn soon became very impressed with his results and the numerous amounts of plants being harvested and sold to aquarium stores. (Nelson, Aquaponic Journal, #10, 11)

Rakocy arrived at UVI (University of the Virgin Islands) in 1980 where his predecessor Barnaby Watter had already started some work on integrated systems. Rakocy talked to UVI about continuing what Barnaby had started and there were no objections. Rakocy was finally able to combine his interests in raising fish, helping people in developing countries by providing food, and waste water treatment. The University of Virgin Islands is a land-grant school with a mission to do agricultural research that is relevant to the islands; which have very limited freshwater resources. Over fishing in the Caribbean caused approximately 80% of fish supplies to be imported. Rakocy and his new work in UVI became extremely important in creating sustainable methods of growing fish and plants in a tropical climate. For 30 years Rakocy has been conducting extensive research on aquaponics with the help of his research specialists Don Bailey, John Martin, and research analyst Charlie Shultz. Currently the facility has become an Agricultural Experiment Station (AES) that Rakocy directs. He also is the research professor of aquaculture directing the research program and oversees research professors and the facility staff. Rakocy was able to design the first commercially viable aquaponic system by using foam rafts that float on the water to grow plants instead of growing in gravel. His findings account for the majority of the information we know about aquaponics today. Rakocy and his colleagues teach aquaponics classes in the summer which inform students how to set up breeder tanks, collect fry for sex reversal, grade fish in the nursery, monitor flow and water quality in the tanks, manage solid waste and sludge lagoons, plant seeds and transplant, harvest and market vegetables, purge and dress fish for market, and much more. (Nelson, Aquaponic Journal, #10, 11)

Integrating aquaponics into the classroom will benefit future generations greatly. What makes aquaponics such a magnificent science for students is the sheer number of topics it covers. Teachers can use it to teach subjects like biology, zoology, botany, chemistry, aquaculture, hydroponics, ecology, and greengineering. Additionally aquaponics can also help students to understand some subjects that might not be as obvious. For example, physics can be used to study water velocity and gravity flows, social studies can be incorporated through the sustainability aspects of aquaponics, math can be used to calculate flow rates, culinary for preparation and harvesting of kitchen herbs, graphic design and architecture can be used for system design, and carpentry to construct the systems. The hands-on aspects of aquaponics allows for great lesson plans that the students will enjoy. Students will want to learn water chemistry to ensure the survival of their fish or adjust nutrient levels for maximum plant growth. Hands-on experience dealing with live animals and plants will bring excitement to students and the ability to see growth over time will help solidify interests. (Lennard, 8)
Generations of students being taught aquaponics will grow up with knowledge absent in many Americans today. Future students will become more aware of the increasing need for fresh drinking water, the negative effects conventional farming has on our planet, and the loss of sustainable farming for the family. Hopefully these students will become enlightened to the importance of going green in all aspects of life in order to keep our planet healthy.

One example of how aquaponic students are already making a difference can be found in Dade City, Florida at the non-profit Morningstar Fisherman Farm. Programs offered through Hillsborough Community College and St. Leo University allows students to take aquaponic classes at the Morningstar Farm. Students “learn how to operate the systems and take that knowledge back to countries like Haiti, Dominican Republic, and Guatemala where they work with local groups to create community aquaponic systems”. (Victoria Parsons, 2) They learn everything from operating a system that can feed a small community to backyard systems large enough to support a family. After returning to the US students help raise money to build large enough systems to provide jobs and food for towns in need. (Parsons, 2)

The benefits of aquaponics are vast. After 25 years of writing about aquaponics, Geoff Wilson believes the greatest benefits include multiple revenue streams with emphasis on species choice, superior produce for local fresh markets, harvesting of organic waste, miserly water use, small land footprint, simplified control over hydroponics, diversified markets, and reduced “food miles”. Multiple revenue streams allow for much “greater business resiliency”. (Lennard, 27) In addition to fish and plant revenue, aquaponics also has the potential for education, tourism, composted organic waste, and processed fish (smoked or preserved) revenue. Selection of fish and plant species allows growers “to tailor output for local fresh market needs”. (Lennard, 27) The capability of changing plant crops quickly gives growers a more diverse stock to achieve the most profitable produce for local markets at any given time. High-end restaurants are always looking for superior fresh produce to use for their dishes. These restaurants will pay top notch for basil that was harvested that morning or fish taken out of the water hours before being served. Additionally aquaponics can be considered organic because no pesticides or herbicides can be used or the fish will die. Maximum profit can be achieved by using the benefits of aquaponics to sell crops. Instead of bringing produce to local supermarkets, selling to restaurants and farmers markets will provide highest possible profit. (Lennard, 28)

The growing need to reduce climate change and greenhouse gas emission (through fossil fuels) encourages a drop in “food miles”. “Food miles” refers to the distance food needs to travel to reach its market. The ideal “food miles” distance will be achieved when food is transported within a hundred mile radius of the marketplace. “Aquaponics is a food production technology that focuses on healthy fresh supply for local markets”. (Lennard, 29) As aquaponics becomes increasingly popular more and more urban farms will be started. Simplified control over hydroponics allows farmers new to the industry to be successful with relative ease. Aquaponic technology is considerably simpler than organic hydroponics “where precise controls on a number of factors are mandatory for good production”. (Lennard, 29) Small land footprint enables new growers to start operations without high capital costs. On less than one acre, Dr. Lennard was able to create an aquaponic “farm-let” able to support a small community with Murray Cod and fresh basil. Dr. Rakocy has also demonstrated the effectiveness of land use in his Virgin Islands systems that provide the island with fresh tilapia and lettuce among other things. (Lennard, 28) Aquaponic technology has been said to increase land productivity six to eight times more efficiently than conventional farming in market garden vegetable production. (James Dixon) Ease of use, numerous profit opportunity, and need for organic fresh vegetables will spike the number of urban farms being started in years to come. When numbers of urban farms increase, market garden vegetable production in local communities will increase, which will then decrease distance our food needs to travel. As the distance food travels decreases, oil usage will drop and quality of produce eaten will increase. Transportation is not the only issue being solved. Chemical fertilizer companies are highly dependent on oil companies for their production. Crops become dependent on “chemicals and fertilizers derived from oil”. (Brown, 8) Reduction in the use of these chemical fertilizers will also help to drop oil consumption. Making aquaponics an economical and ecological solution to the increasing oil issues.

In addition to helping solve our issues with oil, aquaponics is already starting to be used to solve a crisis present in many countries; fresh water. Countries like Australia have become exceedingly dry due to effects of climate change, and soil quality has diminished leaving “millions of square miles of barren plain”. (Brown, 8) In order to solve their problem Australia has turned to aquaponics for help. Although hydroponics and aquaculture are very efficient with water use, they both still require water to be replaced on a regular basis. Whereas in aquaponics “the only water lost from the system is through evaporation and transpiration from the beds and plants.” (Brown, 11) Fish prefer to be in a shaded area due to fear of predator birds. By constructing a roof for fish rearing tanks, rainwater can then be harvested from the roofs to restock any water that may be lost in the system. (Brown, 12) This eliminates any dependency on water other than the initial set up. If the majority of fresh market vegetable production is converted to aquaponic technology, the savings in fresh drinking water would be astronomical. As previously stated, 3/4 of the worlds fresh drinking water is used by farms for plant production. (Jones, 15) Even if that number can be reduced to 3/5 with the help of aquaponics that would increase availability of fresh water by thousands and thousands of gallons. The saved water could then be brought to countries in Africa, South America, or Australia who are in dire need. Bringing this technology to third world countries with limited water supply will also be beneficial in food production. Most of the places that have limited water supplies also have limited food supplies because there is no water to grow produce. Aquaponics would allow third world countries to get the absolute most out of what little water they have. Providing the poor with fresh vitamins (plants) and protein (fish) to survive.

A revolution of food production has swept across the plains of Australia. An increase in oil prices and a lack of fresh water forces Australia to import nearly all produce. By the time vegetables reach the shelves they are overpriced and “would hardly meet health department standards”. (Faye Arcaro, Issue 54, 24) Garden consultants have reported 90% of their clients have become interested in vegetable gardens, “in stark contradiction to the numbers around 4 years ago, when only 10% of clients were interested in vegetable gardens”. (Arcaro, 25) In 2006, Joel Malcolm was featured on ABC Gardening Australia to display his suburban aquaponic system. Joel’s goal was to “show people how easy aquaponics was and, ultimately, he wanted to see a system in every backyard.” (Arcaro, 25) Joel and his colleagues opened a website providing people with free information and online forum discussion about aquaponics. Backyard Aquaponics was born. Word of this new science spread like wildfire in Australia due to the extreme need for better quality produce. Backyard Aquaponics was able to expand and now boasts a facility with “over 12 different systems ranging from compact apartment systems through to a working model of a commercial scale aquaponic system”. (Arcaro, 26) Additionally they employ up to nine staff with roles that include magazine production (Backyard Aquaponics Magazine), graphics, article writing and documentation, system installation, customer service, system and product development, and retail nursery duties. Grants from the Stephanie Alexander Kitchen Garden Program have allowed many schools in Australia to start incorporating aquaponics into the classroom and culinary programs. Additionally due to interests from teachers and TAFE (Technical and Further Education) colleges, students have had the opportunities to visit the Backyard Aquaponic facilities to get even more hands on experience.

The urban farming industry in Australia is booming in the form of backyard aquaponics. Australia was faced with problems that will soon become present in more and more continents around the world. As these problems become present aquaponics will be there to help provide a solution. An increase in families growing vegetables for personal use will occur as aquaponic information becomes more standardized. Food production in the future will require ecologically sound practices and aquaponics will provide that.
The future of aquaponics will most likely be headed in only one direction; urban farming. As Dr. Lennard states in a recent interview “the time for the small scale farmer is returning.” (Lennard, 4) Contrary to what many people think, Dr. Lennard believes that large aquaponic facilities will not become the wave of the future, rather incorporating this technology into urban farming will. Dr. Lennard justifies this by explaining how “oil is running out and we will need food grown close to where we live again (like in the past)”. (Lennard, 4) Of course large facilities will be built and are being built, but he believes this is not where the emphasis on the future of aquaponics will be. By building facilities acres in size the problem of transporting produce is still present. In order to ensure highest quality product and still take in consideration depleting oil, “decentralized growing systems will be set up in cities and towns throughout the world”. (Lennard, 4)

Aquaponics will never be able to become the primary form of agriculture. Dr. Lennard explains that “the most important agriculture products, the ones that feed the world, are the cereal crop staples which provide basic carbohydrate requirements for us all, things like rice, corn, wheat, etc… These are broad acre crops and we grow millions of hectares a year globally”. (Lennard, 3) It is just not practical for aquaponics to ever reach that level. The amount of acreage used to grow these cereal crops is far too vast. However, aquaponics will still make a noticeable difference in the farming industry in years to come. It has the ability to take over the hydroponic industry completely and perhaps even dominate the market garden vegetable production. The first step towards this goal is to educate the masses about what aquaponics is and its amazing benefits. As the information spreads, the future of urban farming will be born. Backyard aquaponics will become a global phenomenon instead of being limited to primarily Australia.

“There is a phenomenon in technology evolution whereby the first 90% of the optimization is done quickly and the last 10% takes years”. (Lennard) In the following years to come aquaponics will reach full maturity. For a relatively new science it has grown exponentially over the past 30 years. Aquaponics has reached “the last 10% stage” and will require a push of inspiration, not only from researchers, but the average Joe to fulfill that last 10%. The urban farmer and hobbyist alike will be vital in order for aquaponics “to move towards the most efficient approaches possible, to use as little water as possible and to use as many nutrients as possible.” Other countries, such as Australia, have already realized how crucial aquaponics is for the future generations of food production. They have supported research for years and have many experts with their PhD’s. As the industry is growing, Americans need to become educated and aware so that the US can have a thriving ecologically sound agriculture. Furthermore, aquaponics will provide many areas for scientific research, exploration and exchange throughout the world. It will also create many new jobs. Aquaponics will offer a solution to eliminate nutrient waste, oil waste and water waste. These solutions will allow us to survive and keep our planet healthy.


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