The case for aquaponics – typically the co-culture of fish and edible plants – as a means to improve food security may be regularly overstated by well-meaning idealists. Yet a range of aquaponics initiatives has proved their worth, as Austin Stankus explains, in the first installment of a new series by members of FAO.
To quote John Hambrey (2013): “There are a lot of people out there spouting nonsense about fortunes to be made from aquaponics”. To be sure, there are more than enough articles touting the benefits of aquaponics. But if aquaponics is so great, why is it not more mainstream? Indeed, surveys show that aquaponic production is still quite limited in terms of tonnes of food produced, and very few companies are economically viable. From a purely commercial or economic development perspective, the disadvantages of aquaponics can often outweigh the advantages. Integrating recirculating aquaculture with hydroponic plant production increases complexity, compounds risk compromises system optimization for either product and restricts management responses – especially in relation to pests, diseases, and water quality. Energy use is relatively high because of the need for both aeration and pumping in most systems. Further questions from a sustainability perspective relate to the use of high-quality fish feeds as the nutrient source for systems focused primarily on plant production. Solar or wind-driven systems are usually required to make them both economically viable and environmentally sustainable, adding to the capital costs. Aquaponic systems have expensive initial start-up costs compared to soil production or traditional hydroponics. Finally, it is unlikely that farmers in developing countries can afford to buy or run high-tech, high-cost aquaponics systems that depend on electricity 24/7.
One successful example is from Indonesia, with a rapidly expanding aquaponic sector. A unique version of aquaponics, called Yumina, is a radical innovation compared to more ‘traditional’ aquaponic systems. Yumina employs a refreshingly simple design, using only local materials with minimal cost. The power use is low, and it is resilient to power outages. The design, in brief, is a 1 m3 concrete tank, densely stocked with tilapia or Clarias catfish. A small pump (<60 watt) lifts water into a distribution manifold of PVC pipe bent around into a circle, which rests on top of plant containers (flowerpots). A hole is drilled into the manifold and the water enters each flowerpot, flows down past the roots and out through the exit pipe, and waterfalls directly back into the fish tank. The media in the flowerpots filters solid waste, and after each harvest, the pot is removed, and the media rinsed (if gravel) or composted (if organic). This innovative design is supported by a dedicated Government research program, and connected to an extension and support system for farmers. An awareness campaign has exposed at least 10,000 farmers to the practice, and about 3,000 farmers have adopted it. While there are some technical issues, the farmers, extension workers, and university researchers are working together through community-based science to address them.
Read the complete article at www.thefishsite.com.