Environmental degradation and industrial and real-estate development are among the factors reducing the space available for conventional agriculture and encouraging the emergence of new methods that are better suited to these changes including aquaponics.
According to a UN report from 2010, as many as 30 million hectares of arable land (that’s an area equivalent to the size of Italy) is lost each year due to erosion, advanced soil exhaustion and urbanisation. Since 2008, the 50% threshold of the global population living in urban areas has been crossed.
One such technique is aquaponics
Aquaponics is a combination of aquaculture and hydroponics (i.e. growing plants without soil). It involves growing plants in suspended structures whose feet are sunk into a fish tank. The fishes’ waste products are absorbed by the plants’ roots and assimilated for their growth, which helps filter the water, so it returns, purified, to the pool (see Exhibit 1). This replicates a natural cycle that is more accurately called an urban food ecosystem. It provides us with fish as well as fruit and vegetables in an environmentally sound and economical way.
Exhibit 1: Feeding the fish in an aquaponics tank results in waste products, which the plants absorb and use for growth, causing the water to be filtered, so it returns purified to the tank.
The foods are sustainably produced without using chemical fertilisers – the plants are fertilised by the waste products of the fish – or pesticides which would kill the bacteria needed to maintain the ecosystem. Minimal waste is ejected into the environment and the system uses 80% less water than is the case with industrial agriculture.
The foods are highly economical as their potential yield is 10 times greater per square metre, crops can be grown year-round and, since there is no contact between crops and soil, mineralised, sterile or other soil that is unusable in conventional agriculture can be put to use.
A replicable aquaponics model confirming these parameters has already been tested at a site in Morannes, in the Maine-et-Loire department of France.
The only input into this loop is fish feed. And even here there have been innovations such as granules produced from organic waste. The processing of bio-waste into proteins using a natural process produces a complete food source for fish farmers, thus reducing their sourcing costs and limiting their crops’ environmental impact.
The era of sustainable development
While there is no guarantee that aquaponics will be successful in the future, this example does illustrate the efforts being made to resolve environmental problems at the dawn of the new era before us – the era of sustainable development. As a manager of environmental funds, BNP Paribas Asset Management takes a keen interest in all sustainable development solutions that, like this one, can help us adjust to global warming in the coming years.