Is Aquaponics a solution for South African food security?

With the world population growing, increasing pressure on agricultural land for the production of bio fuels, dwindling natural resources and the ecological impact of intensive farming techniques; where will our food come from in the future and at what cost?

In South Africa we also have a long term problem looming with water supplies (recent concerns from the EU regarding river pollution may seriously restrict South African farmers from exporting crops such as grapes), not only quality but also quantity. Our commercial farming relies heavily on crop irrigation from river systems and drawing water from the water table.

As our demand for food far outstrips our local production we become increasingly dependent on imports. This is a two fold problem: first, we are then dependent on another country; we no longer have food security and cannot control production, price, quality or consistency of supply. Secondly, our food costs become intrinsically linked to the cost of transportation, which in the short, medium and long term is set to rise dramatically.

It is unlikely that our water supply will increase, more likely we will see a decrease in usable water, and without more water we will not be able to create oasis in the desert. So how can we ensure our own food security?

For one thing our eating habits will have to change to incorporate more local produce; not just locally produced, but stuff that actually wants to grow here.

And we also need to tailor production methods to suit local conditions, ie, long periods of dry weather.

We recently got interested in aquaponics as a possible alternative to traditional cultivation. It seems to tick a lot of boxes for the local conditions and we are going to give it a go- so I have started a companion blog to chart our progress at

If you don’t know what aquaponics is, it is a semi-closed ecosystem which makes use of the symbiotic relationship between plants and fish. A tank of fish turn fish food into waste, this collects in the fish’s water and will eventually kill the fish. So the water needs to be constantly cleaned in order to keep the fish alive. In an aquarium this is done with a series of filters and pumps, which constantly moves the water through the filtration system. Eventually the filters need to be removed and cleaned.

In aquaponics the water is pumped out of the fish tanks onto growing beds where bacteria then convert the ammonia and other fish wastes into fertilizers that the plants make use of. The water then continues through a filter bed until it returns to the fish tanks clear and oxygenated ready to be messed up again.

The advantage is that the plants are fertilized in a completely organic way and you get the addition of producing both protein and vegetable at the same time.

Aquaponics also uses significantly less water than conventional crop growing, which for South Africa is a real plus. If you think about normal irrigation (or watering of plants at home) a lot of the water just runs off, and, although a sensible gardener will have some kind of mulch on the ground, a lot of moisture will be lost to evaporation. Aquaponics uses a closed loop of recycling water. Some water will be lost to evaporation but it will not be as significant as if the water was being poured on the ground and all the associated run off.

And the plants love it- all that nitrate rich fertilizer on constant stream and plenty of water.

So why are all farms not aquaponics?

Consumer taste has everything to do with what is farmed, and to a certain extent, how.

And there is a question of cost. The farms are already established the way that they are and to convert them to a different system would be very expensive, that’s a lot of risk in difficult times. Commercial farms are more or less locked into their current crop cycles. Tie this into commercial demand and you can understand why a farmer would not wish to change what they are doing. Fish is a popular food but we tend to have a taste for salt water fish, fresh water species are less desirable, and if it was a type of fish that was not familiar to consumers would it sell at all. Tilapia is the species of choice around the world for aquaponics where the fish are to be eaten. It is a restricted species in South Africa though and an accidental release into a local river system would be devastating.

It would be great to see someone take on a large scale operation, especially in an urban setting (there is no reason why such a farm would need to be in a rural environment- old warehouse space could work very well), but it would be more of an experiment than a commercial enterprise.

For the home gardener aquaponics holds more promise. We tend to grow food because we are more in control of the quality (our food security). If you actually sit down and work out how much home grown food costs it isn’t a great saving on shop bought produce- lots of times it is more expensive. A small scale operation is not costly to establish and the yield can be more than adequate for a household. However, food costs are rising and quality is becoming more questionable. Genetic modification, unspecified contents, chemical fertilizers and the rest are all adding to general concern over what we buy in the shop.

Small scale gardening is becoming more and more popular, with non-profit cooperatives, especially in townships, feeding people that would otherwise be going hungry. With financial help to get established, aquaponics could be an option for establishing viable farms in areas that would otherwise be useless for food production.

Not only would this provide food security to communities that are currently struggling but it would be done at source, removing the need for transportation from elsewhere.

There are things to be sorted out but on the face of it aquaponics looks like it could be a serious contender to help South Africa with its future food security. We are sufficiently intrigued to personally look into it further and so have started a companion blog to chart our progress. Just click the link to our Aquaponics blog.

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