How urban fish farming could save our oceans
Why continue to overfish our oceans, when we could instead harvest fish in our own apartment buildings? This may sound like utopia, but it’s already happening.
In an old factory building in Gothenburg, a number of rectangular water tanks are occupying a small area of previously unused space. The tanks are filled with clarias and tilapias; freshwater fish native to Africa, but bred and consumed in many parts of the world.
“They are like pigs that live in water. They eat anything. So instead of taking food from the oceans, we make food from city waste”, said Niklas Wennberg, founder of Pond and Stadsjord, during a presentation at the Ericsson Sustainability talks in Gothenburg.
The two species also grow quickly. In an area of no more than 50 square metres, Niklas Wennberg can produce two tonnes of fish every year — without using antibiotics.
So is the fish tasty, or even edible? Apparently so. It has been served at a Michelin-starred restaurant in southern Sweden for more than two years.
The wastewater from the fish tanks is very nutritious, and could be potentially harmful if dumped in the ocean. But it isn’t. It’s used in the vegetable farm in the same factory building. Two tonnes of fish produce nutrition for 20 tonnes of vegetables. In turn, the production of green plants also helps clean the water before it is pumped back into the fish ponds.
“I grow a hundred kilos of vegetables per square metre. That’s a lot of vegetables”, says Niklas Wennberg.
His innovative work is now being integrated into the world’s first resilient building, Ekobo (PDF), designed by the architectural firm Inobi.
The building will be home to 100 residents in Uppsala, Sweden, and all residents will get their full intake of fish from an inhouse aquaponic farm fitted into a space of 50 square metres. They will also get more vegetables than they need from a 100 square metre vertical greenhouse farm.
The same kind of urban farming concept will be used in a whole new residential area called The Embassy of Sharing (PDF), construction of which will start in Malmö, in southern Sweden, in 2020.
But this kind of urban farming is not just a concept for wealthy people in the Western world.
“We have been asked to present food models for the largest refugee complex in the world, Dadaab in Kenya. This is about saving oceans, and about saving people”, says Niklas Wennberg.
Facts about Niklas Wennberg
Niklas Wennberg is the founder and CEO of Stadsjord, and has spent the last 25 years developing standards and models for urban farming in Sweden and abroad.
He also teaches sustainable development at Gothenburg University and Chalmers University and has been engaged as a key expert in the EU project Refarm Europe.
His company Pond has worked with SIDA (the Swedish International Development Cooperation Agency) to introduce eco labelling of fish in ten countries in South East Asia.
Niklas Wennberg has received many prizes and awards for his work with urban farming and eco labelling of fish.
Web site: http://stadsjord.se/om-oss
Written by: Markus Lutteman
Proof reading by: Jane Davis
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