[ AQUACULTURE ] Urban fish farming: A realistic model or unworldly utopia?
Will tomorrowâ€™s fish be farmed on a roof? As more and more people strive for better quality, freshness and control of the foods they eat, an increasing number is trying to produce part of their daily food requirements themselves, not only in rural areas but in urban environments within the conďŹ nes of large cities. In doing so they hope to inďŹ‚uence production conditions. Is urban farming just an ambitious hobby or is a new method of food production emerging that can seriously compete with established food industries?
hether urban gardening (mostly the small-scale use of urban areas for horticulture), or urban aquafarming (the rearing of fish in small, often only bathtub-sized tanks and facilities of various types) the motives for pursuing such activities are usually identical. The forerunners in this field strive to both produce and consume food locally, thereby saving energy and reducing CO2 emissions through short transport routes. Careful waste management helps maintain natural material cycles. Above all, however, pioneers are looking to produce healthy food in a sustainable, environmentally friendly and socially acceptable manner. And that means without the use of chemicals and antibiotics or other drugs, and without pesticides or hormones, the use of which (according to most urban farmers) was common in conventional industrial food production. With this positioning, the urban farming movement claims to be a better, fairer, more environmentally and climate-friendly method of feeding humanity. To a certain extent it presents an alternative as an attractive model that anticipates the future of our nutrition and brings it into the present day. Apart from the fact that the total production of all urban farms is
currently not even measurable in the per mil range of global food production, the idea of producing food in the city and avoiding complex and costly distribution systems and refrigerated transports that require energy and pollute the environment has a certain charm. City farmers take responsibility for their supplies of fresh produce and contribute towards improving the urban microclimate. Their awareness of and interest in a sustainable lifestyle increases and they experience first-hand the pleasures and problems, the joy and suffering entailed in the rearing of plants and animals. Especially in cities, where more and more people spend their lives far removed from nature, there is growing concern about the way we live and what we eat. People have begun to ask themselves whether certain products can still be eaten at all without health risks. The longing for natural, sustainably produced food has developed into a megatrend in many western societies.
Urban aquafarming often uses aquaponics technology The idea of urban farming has long since reached aquaculture, too. Like locally produced vegetables,
The idea of combining fish farming with plant production has long been practised in Asia. Tilapia are grown there in rice fields, for example.
locally or regionally produced fish and seafood are in tune with the times. Apart from a few producers such as Urban Seas Aquaculture in Greenville (USA, South Carolina) which specialises exclusively in indoor shrimp farming (Pacific white shrimp, Litopenaeus vannamei) the majority of urban aquafarmers combine fish production with the cultivation of plants, mostly herbs or vegetables, in aquaponics systems. The term aquaponics is a composite of the words aquaculture and hydroponics, also called hydroculture. Hydroculture is a demanding, highly intensive horticultural method in which higher plants are cultivated without soil in an aqueous
nutrient solution. In aquaponics systems, fish and plants exist in a certain sense in a symbiotic relationship to each other. The treated water from the fish farming facility (aquaculture) contains large amounts of nutrients, especially nitrates, which serve as a perfect fertilizer for growing plants (hydroponics). The plants extract the nutrients from the waste water and use them for their growth and thus contribute towards purifying the water so that it can be used again for fish production. This reduces the need for new/fresh water by 80 to 90 per cent compared to conventional aquaculture. Economical water consumption combined with relatively small space &VSPlTI
Featuring Norway, Estonia, and Slovenia, this issue of the Eurofish Magazine looks at urban fish farming in the aquaculture section