The farm is located on the site of a former malt factory in the middle of Berlin-Schöneberg, within walking distance of the Tempelhofer Feld. When entering the hall, visitors encounter the tropical, humid heat. Twelve high, round pools of water stand in the moist warmth, in each of which a swarm of Nile tilapia from the cichlid family does its rounds. Next door in the light greenhouse, thousands of herbs spread their aromatic scent. On this urban farm, the ECF Farm, the so-called capital perch and the so-called capital basil are raised under one roof. The plants are poured with the used water from the perch tank – the excretions from the fish serve as fertilizer for the basil. A principle that sounds temptingly simple.
Aquaponics is the name of the resource-saving process that combines the rearing of fish with the cultivation of useful plants. Such projects have existed in Germany for about ten years. In the initial euphoria, there was talk of a “new agricultural revolution”, there were start-up and sustainability awards. That was often justified, but also very early. Even a decade after its introduction, aquaponics is still far from being widespread enough to bring about real change. There is also room for improvement in terms of sustainability and CO₂ consumption, as can be seen at ECF. As the largest German facility of its kind, the farm is a good place to take stock.
The so-called capital basil grows here. It is fertilized with fish excrement, which has been converted into nutrients by bacterial culture.
Linking animal husbandry and farming is an old idea in itself. The settled man increased his yield significantly when he began to fertilize his plants with animal excrement. In this sense, aquaponics is the high-end further development of a cultural technique. But is it really the model for the food supply of the future, in which an ever larger world population wants to be satisfied with increasingly scarce resources – and that as environmentally friendly, animal-friendly and sustainable as possible?
Global fish consumption is also increasing worryingly. In the 1960s, just under 3.5 billion people ate an average of nine kilos per head. Today it is just under eight billion and 20 kilos. According to the environmental organization WWF, around 85 percent of the fish in Germany, like in the holiday countries around the Mediterranean Sea, is imported, half of them from distant developing countries. There are often warnings about how devastating this will affect the local populations and the global climate, most recently – particularly impressively – in the Netflix documentary “Seaspiracy”. Sustainable seafood, they say, simply doesn’t exist. If we carry on as before, the seas will be empty in 2048.
If we carry on as before, the seas will be empty in 2048
Farmed fish from aquaculture, from which every second food fish comes today, is just a little less problematic: The intensive operation of fish farms pollutes lakes and seas with chemicals, antibiotics and the excrement of the fish.
Aquaponics is considered an elegant solution to all of these problems. Fast-growing, robust freshwater fish such as Nile perch or trout are kept under controlled and species-appropriate conditions, so they have a strong immune system and do not need any medication. “We give our fish the maximum comfort environment,” says Nicolas Leschke, the managing director of ECF Farmsystems, the operating company of the Berlin facility. “Comfortable environment” may sound a little too much like a vacation, on the other hand, optimal conditions for the fish are of course in the interests of the breeders.
Nicolas Leschke and Christian Echternacht, the founders of ECF Farmsystems in front of their greenhouse in Berlin.
(Photo: Steffen Roth)
In Schöneberg, exactly as many perch swim in the warm water in each pool that the animals neither feel unprotected nor press each other. There is food 12 to 16 times a day, plus extra oxygen. What they excrete is filtered out or converted with the help of bacteria. In this way, ammonium becomes the plant nutrient nitrate, which is enough for the basil next door. The herbs get by without any further fertilization and convert the exhaled carbon dioxide of the animals into oxygen. The cleaned residual water flows back into the basin. This works not only with herbs, but also with tomatoes, peppers, aubergines, cucumbers, melons or lemongrass. According to WWF, one kilogram of fish and 1.6 kilograms of tomatoes can be produced with 220 liters of water. In conventional systems, 600 to 1000 liters of water are required for the same amount.
On the way to an even lower CO₂ consumption through short distances, ECF is planning to breed the baby perch called “fingerlings” soon instead of having them delivered from the Netherlands as before. But feeding the animals is a far bigger problem. Up to a quarter of all fish caught worldwide is processed into fish meal to be fed to other fish on aquaculture farms. With perverse side effects: Chinese farms off the North and West African coast, for example, where popular seafood such as salmon and sea bream are bred, consume more fish in the form of flour than they ultimately deliver to edible fish, including Europe. The foreign trawlers are exhausting the fishing grounds, while the toxic by-products of fishmeal production often end up illegally in the sea. Some already speak of a “new imperialism”.
Farmed fish that should be sustainable must be fed a vegetarian diet
The feed of the Berlin perch also consists of 20 percent fish meal – still. It will soon be replaced by fish food made from algae and duckweed, explains Nicolas Leschke. To protect marine fish, the omnivorous perch is made a vegetarian.
The capital perch is slaughtered once a week and then goes to retail outlets, regional weekly markets or local restaurants, and star chefs also order from ECF. If you want, you can pick up your fish directly from the farm on the day of slaughter. Cooked on the grill or in the oven, just seasoned with a little salt, it is just as tasty as a ceviche. The harvest from the capital city basilica has been packaged plastic-free in Berlin’s Rewe stores since 2018, 450,000 plants per year.
In itself, the aquaponics system works well. But does it really represent the future of animal protein production for human consumption?
The modern farm is sustainable, but certainly not romantic: seedlings under artificial light in Berlin.
(Photo: ECF Farmsystems)
The farm produces up to ten tons of perch a year, which at almost 2,000 square meters takes up the area of two 50-meter swimming pools. That is just as much fish as 500 people consume on average each year.
The method is still operating in a niche that is so small that even the Federal Aquaponics Association has no figures whatsoever from which one can read what proportion this makes up in the overall fishing industry. Two other commercial providers are currently working with the technology in Berlin and Brandenburg, and there should be a handful across Germany. That doesn’t sound like a real revolution. But the Berlin aquaponics facility functions primarily as a kind of test laboratory, with which the operators continue to improve the process and make it better known. With the knowledge gained, ECF Farmsystems builds systems for other farmers, for example in Switzerland and Belgium, so the number of farms and their product range should grow.
Nile perch from the city farm: The quality is so good that even star chefs order it.
(Photo: ECF Farmsystems)
Others take the principle even further: A joint project by several research institutes and universities under the direction of the biologist Christian Ulrichs is also working on a solution for more sustainable food production. “Cubes Circle” are stacked production units the size of shipping containers. As a third element, in addition to fish tanks with cichlids or silver carp and greenhouses with vegetables, there are insect farms on which larvae are raised for food for fish (and potentially also for humans). This year, a pilot plant for this “cube-shaped farm” is to be built on the campus of the Free University of Berlin in Dahlem.
At ECF Farmsystems, too, people have long been thinking ahead. In Wiesbaden, Nicolas Leschke and Christian Echternacht opened their first farm on the roof of a supermarket at the end of May. There they breed the tried and tested combination of perch and basil – which goes on sale in the market below without a transport route. In the next five years, another 20 such roof farms are to be built across Germany, after which the expansion abroad is on the agenda.
Short goods routes: In Wiesbaden, a supermarket with a greenhouse and fish farm has just been built on the roof. The first of its kind in Germany.
(Photo: ECF Farmsystems)
But the farm on the roof of the supermarket has its limits, especially spatial ones. “Cities are primarily there to live, not to grow food,” says even Nicolas Leschke himself. City farms are a niche, albeit an important one. This is the only way people can understand what it means to produce food again. Much more sensible for the actual nutrition of the city dwellers, however, are aquaponics systems on the edges of metropolitan areas, which offer enough unused space for larger cultivation and breeding areas. A tenfold increase in the currently cultivated area per farm to two or three hectares is easily conceivable. The maximum size you can grow such a farm has simply never been tried. One thing is clear, however: Ideally, it would be located in the immediate vicinity of the central warehouse of the large supermarket chains, from where sustainably produced food can then be distributed to the shops. And if agriculture were to take place in the already more soil-sealed bacon belt, it would not eat up even more space outside the cities.
“As humans, we have to become more efficient in all areas, including food production,” said Nicolas Leschke. “That means using fewer resources in less space.” So there are alternatives that work commercially, as the city farmers are already proving. But they also know that even after ten years of experience with aquaponics, there is still a lot to do. The change has only just begun.