It sounds smart and sustainable: combining fish and plant farming by using the fish’s waste water to feed the plants. The theory is great, but aquaponics proves to be rather unruly in practice. Wageningen research reveals it only pays in regions where both fish and vegetables are expensive.
© Aquaponics Philippines
Around the globe, there are approximately one thousand companies involved in aquaponics – the combination of fish farming and water-based agriculture. Half of those companies are making losses, says Roel Bosma of the Aquaculture and Fisheries group. He supervised a group of Wageningen students who worked on an assignment for the course Academic Consultancy Training (ACT). The question they worked to answer is one of a Dutch investor who asked how he could make his investments in fisheries and agriculture in the Philippines profitable.
The students performed a literature study and calculated the potential production and costs of the company’s system that produces freshwater fish, lettuce and tomatoes. The Filipino student within the six-person ACT group took it upon herself to research the local market. Their conclusion: the combined farming only has a chance of succeeding if the entrepreneur finds a good niche market for expensive fish and combines it with lettuce and tomato farming, as these vegetables are relatively expensive in the Philippines.
Aquaponics is a huge hype at the moment, states Bosma, who compares it to the hype several years ago around a genus of jatropha that can be used for biofuel production. Within the frame of circular economy and recycling of materials, the idea of growing vegetables on water from a fish pond that is filled with nutrients is beautiful. But Bosma mitigates the expectations by reminding that if one does not keep an eye on the market prospects, it might become a financial disaster. Together with several students, he elaborated the ACT report into a scientific article that was published in Aquacultural Engineering.
‘A recent American study among two hundred aquaponics farms around the globe revealed that more than half of these companies are making losses. The business is not viable with tilapia or catfish, as those are much too cheap. One really needs to find a niche market for expensive fish, and that fish farming part should be in financial equilibrium’, Bosma explains. In Belgium and the Netherlands, one could try zander, burbot or jade perch. ‘Additionally, the vegetables should be fairly priced as well. The companies on Hawaii, where the hype originated, generally fair well, as the prices of vegetables are often high on islands.’
Aquaponics are not likely to be profitable in the Netherlands, says Bosma. ‘There have been three research projects in the Netherlands, and each one concluded that farming fish would be relatively too expensive. Besides, the Netherlands rarely have niche market possibilities for vegetables, as Dutch agriculturists will soon provide the niche market with much cheaper produce.’ Bosma adds that the environmental benefits that can be achieved here are limited, as recirculation of nutrients is already applied in aquaculture and agriculture.
But combination farming will also have a hard time in a country like Ethiopia. ‘The first choice is often tilapia, as its fry is readily available, but that encounters heavy competition from the frozen tilapia that the Chinese sell throughout most of Africa.’
The ACT group advises the investor in the Philippines to start out small and by farming catfish. ‘The small units are less vulnerable to storms and can be easily upscaled’, says Bosma. ‘Catfish is less susceptible to low oxygen levels, allowing the aquaponics farmer to gain experience. After a few years, the farmer could switch to a species with a good niche market, such as the jade perch or the local lobed river mullet. The farmer must also learn how to finetune the combination farming, as the nutrients from the fish rarely fully overlap with the requirements of the vegetables.’