Introduction to Aquaponic Farming

From backyard hobby to commercially viable farming

In recent years, Aquaponic growing systems have transformed from a DIY backyard project to a viable growing alternative in the commercial agriculture sector. Hobbyists around the world have created and refined a plethora of approaches to the symbiotic relationship between plant, fish, and bacteria. This has lead to the technical knowledge and skills which have allowed broader thinking individuals to create a new niche within the farming industry: a sustainable and resource-conscientous sector that produces some of the healthiest plants and fish. This is done at a fraction of the resource demands one regularly finds within the incumbent growing methods of large scale farmers around the globe.

The Sustainable Harvesters’ greenhouse in Hockley, Texas.

What is Aquaponics? Where do the concepts and principles of Aquaponics stem from? Are there economic benefits? Environmental? Nutritional? From what I have found in my research, there are economic, environmental, nutritional, as well as sociological and mental health benefits to be found through these sustainable micro-environments. 

Let me begin with the name, aquaponics. This is a mash-up of the terms aquaculture and hydroponics, aquaculture relating to the farming or raising of fish species, and hydroponics meaning a method of growing plants which does not use soil. One benefit of this is the reduced surface area necessary to farm on.

Within an aquaponic system, a symbiotic relationship is formed between the fish and plants, which is fostered and maintained by the farmer through bacterial colonies. While I say this relationship is symbiotic, it is skewed in favor of the plants and hungry bacteria which thrive on the chemical waste supplied by the aquaculture. The aquaculture factor in this equation will require input in the form of fish feed, and one will want quality when selecting this.

Nitrosomonas, ammonia-oxidizing proteobacteria. This microbe is one of many capable of nitrification.

In simple terms, fish create waste which can be used to feed the plants in the system. Fish excrete a chemical known as Ammonia through their gills as well as through their urine and feces. This ammonia can be toxic to the fish in large quantities if it is not handled accordingly. This is where the bacteria comes in- bacterial colonies oxidize the ammonia within the system, a form of biological filtration. This oxidization of ammonia, known as nitrification, then creates a biological compound which is then sufficient to be absorbed for use by the plants. 

Now that I’ve provided a fingerling of knowledge regarding the life cycle of an aquaponics system, let’s take a step back and see what one can discern about the origins of aquaponics. To understand aquaponics, one must be familiar with the concept of biomimicry, which is the design and production of materials, structures, and systems that are modeled on biological entities and processes.

Biomimicry and the origins of Aquaponics

The archaeological record shows evidence that modern man’s ancestors began using rudimentary tools up to 3.6 million years ago. A ancestral grasp of meaning in the world around us other than immediate hunger and survival, though it was undoubtedly driven by these factors. Leaps and bounds later we began to conceive of systems through our observation of the world around us.

This conception began similarly to the use of tools, through interaction with the environment and seeking to exploit rather than preserve. We first noticed seasons as hunter-gatherers which aided us in seeking the ripest forage. We cooperated with others within our race and then learned to cooperate with the world around us more thoroughly. Our understanding of seasons evolved to our navigation of the seasons in agriculture, with civilizations such as the Aztecs thriving in unique ways.

Back around 1000 A.D, the Aztecs used a systems of artificial islands called chinampas. Often built in shallow lakes or swamps, the chinampas used canals to host schools of fish which aided crop growth through the use of their waste and could be harvested as well. The Aztecs learned to manipulate and replicate their ecosystem through a symbiotic relationship between humans and their environment.

In addition to the Aztec methods, there is evidence to support that early cultures in South China, Thailand, and Indonesia also used biomimicry to create beneficial aquaponic systems. The ancient Chinese would even house ducks or other fowl over ponds so their droppings could be metabolized by the fish and in turn the fish waste was sent to the bottom of the system to be used as irrigation for rice and vegetable crops. Other farmers would even incorporate fish directly into the muddy waters of the rice paddies.

In contemporary society, an increasing amount of individuals are seeking to advance this early form of biomimicry. The media and academia alike now spend a deal of time and resources into discussing the topics of man-made climate change and it’s repercussions. One particular area of significance in regards to climate change is agriculture. Many have begun to examine alternative farming methods, with aquaponics as one viable option. My own research has repeatedly brought me back to one source that is cited by many in the aquaponics community: the research organized and overseen by Dr. James Rakocy at the University of the Virgin Islands between 1980-2010.

Dr. Rakocy’s official title was Research Professor of Aquaculture and Director of the Agricultural Experiment Station. Throughout this time he drove high-volumes of research on tilapia in warm-water aquaponic systems and helped pioneer the benchmark standard for conservation and recycling of water and nutrients within a closed-loop system (a system which is as self sustaining as possible without the use of harmful chemicals).

Diagram of the system developed by the University of the Virgin Islands.

One can infer with a little imagination the jump from Aztecs utilizing canals of local fish to harvest nutrient dense fertilizer for their crops; to the modern system by the UVI. Here we see the basics of the system used from both the ancient adaptations to the present: fish make waste, bacteria converts this into a biological compound fit for plant consumption, the plants consume and help clean the water. For maximum efficiency, in a modern system you will find additional fail-safes such as ultraviolet sterilization lights and swirl filters to further maintain water integrity and the health of species within the system.

These farming methods are complex tools but versatile on many levels.

Due to aquaponics’ biomimetic foundations, this allows for variance in the environment which can host the beneficial microbes as well as the plants and fish species within. Aquaponics can operate in both warm and cold water environments, which creates opportunities to provide a diverse range of crops and fish species. This is not without it’s caveats, the proprietor of an aquaponic ecosystem must understand the implications that this diversity brings with it: water temperatures must be precise for bacteria to thrive and growing in a cold water environment may require supplemental lighting for the plants.

Raincoast Aquaponics on Vancouver Island, British Columbia is an example of a cold water system.

Shared Foundations

Whether using cold water or warm water within a system, the principles remain the same. Microbes nitrify fish waste and convert it into nitrates for plant consumption. Water circulates through the system continuously in a steady flow of filtration and nutrient absorption. Cold water fish versus warm water fish may have need for a slower flow of water or less fish feed due to metabolic changes in this brisk environment. While there will be variances in the needs of your plants and aquaculture, a few key items remain the same.

  • Plants will need sunlight and possibly supplemental lighting.
  • Bacteria is necessary in the system, but only the right kind of microbes will suffice. Though the number of nitrifying bacteria are said to number in the thousands. Pathogenic bacteria will need to be eliminated from the system through more advanced filtering methods such as Ultraviolet sterilization.
  • A certain amount of bacterial surface area is required (a ratio of the number of bacteria to a measure of space).
  • Temperature control is essential to the health of your plants and fish. Without the right temperature range this can cost the lives of your fish cohort and subsequently your plants.
  • Various levels of filtration should be implemented to allow for the proper amount of waste to circulate through the system and allow for bacterial nitrification.
  • Large waste particles (effluent) will need to be regularly purged from the system (this can be saved and used for other purposes such as fertilizer or spread into a worm bed).
  • Your fish will still need to eat, though certain plants can be grown to supplement their diet and offset costs.
  • Certain pH levels will need to be maintained depending on fish and plant species.
    • Plants may require additional nutrient supplementation.

The Benefits

While aquaponics is not a perfect method of farming, it is closer than many used in the past and stands as one of the most efficient forms available today. What do I mean in terms of efficiency? Resource stewardship, which leads to an abundance of nutrient-rich product at the end of this biological and chemical exchange is the goal here. That is efficiency, to make as high quality of a product as possible while balancing it against the cost of the building blocks required to produce such.

A comparison chart borrowed from Ali AlShrouf, of the Abu Dhabi Food Control Authority, R & D Division, AlAin, UAE.

One can see from Mr. AlShrouf’s research that water use in an aquaponics system is significantly lower than in conventional agriculture, which is the use of open air soil crops with added nutrients and irrigation system. While the chart shows the other categories pull ahead in certain areas, they all have their strengths and the chart shows only a piece of the picture.

One trait these methods all share is their use of a fraction of the land required to achieve the same crop ratios in large scale conventional agriculture. They also allow for improved product quality through more precise environmental control. This control lends itself to a homeostasis within the farm and the plants thrive on this.

More on this in future articles as well as more detailed insight on the practical application of a aquaponic environment.