Fish and the City

Combining aquaculture and hydroponics, Aquaponics provides a sustainable food production option right in your own backyard.

Autor*in Anna Rees, 04.30.13

Combining aquaculture and hydroponics, Aquaponics provides a sustainable food production option right in your own backyard.

Our food system is in a state of flux. Irregularities in weather patterns lead to low crop yields which lead to food shortages which in turn drive food prices up. We’re told that the food that we can get our hands on is cloaked in chemicals and heavy-duty pesticides and our produce clocks up more time in transit on its way to the stores than your average backpacker does. Amidst all this chaos, food-engineering companies are piping up, claiming to have created the silver bullet through genetic modification. No wonder some people have decided to unhitch their food wagon from the global system and go about cultivating their own produce. Here, we take a look at one avenue of self-sustainability within the food prism: Aquaponics.

Aquaponics fuses a harmonious link between aquaculture (growing and breeding fish) and hydroponics (growing plants without using soil), with one system working to benefit the other in a cyclical fashion – essentially, waste from the fish is used to nourish the plants.

Generally speaking, aquaponics systems are comprised of fish tanks and greenhouses. The water from the fish tanks is filtered for fish effluent which is then funnelled into the greenhouses. The waste that is produced by fish (made up predominantly of ammonia) is generally thought of as toxic. However, when fish waste is produced within an Aquaponic system, naturally-occurring bacteria transform the ammonia into nitrite and, subsequently, nitrate, which is choc-full of plant-friendly nutrients. The plants absorb the converted waste and release the clean water back into the fish tank. The result is a completely self-sustaining, symbiotic scheme that allows you to farm your own fish and grow your own vegetables.

There is, of course, a science behind ensuring a healthy, balanced build-up of bacteria along with achieving the right water quality which is why it is always recommended to arm yourself with as much knowledge as possible. But done the right way and the results speak for themselves.

Four years ago, urban gardener Anirban Chanda set himself the small challenge of seeing how much produce he could grow on a rooftop smack bang in the heart of Kolkata. Using an Aquaponics system, the results were so successful that Chanda has been able to set up an entire business, Urbagrow, based around his flourishing rooftop garden, parlaying his knowledge and experience about this niche but growing form of urban agriculture.

“Amongst many other things, [Aquaponics] allows us to grow great quality produce ‘cleanly’ without any dependence on soil availability or quality” Mr Chanda states when asked about the benefits of Aquaponics. “It allows us to reduce food miles drastically by growing in unused urban spaces closer to points of consumption. It allows a higher density per square metre and faster growth rates to grow in, hence, [it] can be highly efficient.” Two of the other large benefits that he discusses are water efficiency (actual figures vary but it has been claimed that Aquaponics uses anywhere between 10 – 90 percent less water than conventional agriculture) and the creation of oxygen-rich green spaces in urban areas.  

Check out the video below for a look at what exactly is growing on that rooftop in Kolkata:

Though labelled by some as space-agey, the practice is by no means new and has some of its earliest traceable roots in Ancient Egyptian and Aztec culture. The precarious state of the food industry coupled with the growing reliance upon chemical-based fertilisers was what prompted Mr Chanda to take food production into his own hands but he is hesitant (or, perhaps, realistic) when it comes to analysing whether or not traditional techniques can achieve widespread application in the 21st century. “Would be nice [but] unfortunately, this is not a battle traditional techniques can win in my opinion” Mr Chanda laments. “It would be ideal but in reality, especially in India, the chemical-dependent (fertilisers and pesticides) agricultural model brings development [about] faster because it ensures high yields and lower crop losses. The fact that it has a higher public cost appears to have little relevance in a developing nation of this size.”

While certainly not the all-encompassing answer to the problems our food system faces, Aquaponics could provide a certain level of respite to flow on effects from key issues including overfishing, climate change and food security.

As the climate shifts and rainfall patterns become more and more irregular, water supply and arid soil could become an issue for certain, water-dependent agricultural sectors. Aquaponics circumvents this – plants are rooted in shallow pools of recycled water (not soil) while fish waste provides the nutrients.

Industrialised fishing is wreaking havoc on fish stocks and delicate marine eco-systems, upsetting the balance of life under the waves as fishermen and fishing companies employ all manner of gadgets to ensure a larger-than-ever-before catch to feed our growing global population. Farming our own fish would negate our need to rely on the global fishing industry (plus there’s the added benefit of knowing exactly where the fish on your plate came from).

Aquaponics could also play a small role in bolstering food security. “A crucial albeit limited role,” Mr Chanda states “primarily, because there are limitations to what can be grown and also because grains carry the most weight in food security numbers and this is not something that is aquaponically feasible yet. Having said that, I do believe each and every little thing I grow has benefits, regardless of statistics.”

Therein lies the key to Aquaponics’ ability to address global issues – while not purporting to contain all the answers, it can be one part of a more integrated approach to sustainable living.

As Mr Chanda himself states “Aquaponics is possible and amazing, but does require will, knowledge and dedication. Self-sustainability is a coalition of many little actions and is extremely rewarding at any scale.”

Looking to set up an aquaponics system up for yourself? Urbagrow has some nifty, easy-to-manage systems as well as lots of useful advice and of course there is a wealth of information online (check out Urban Farming Guys as a starting point) while a detailed (though highly individual) walkthrough of some of the commonly claimed advantages and disadvantages of Aquaponics can be found here.

Author: Anna Rees/ RESET editorial

Urban agriculture and the food security problem

The Hindu Business Line recently ran an article detailing how urban agriculture is a key means of addressing issues surrounding food security.