Professor Werner Kloas, Tomatofish project coordinator. (Photo: EC)
Tilapia and tomato become good allies to save resources and avoid emissions
Wednesday, November 16, 2016, 22:50 (GMT + 9)
In a German institute an innovative emission-free method for jointly producing tilapia and tomatoes has been developed in an attempt to save resources.
The project -- called Tomatofish -- was created by Leibniz Institute of Freshwater Ecology and Inland Fisheries based on the idea of using a double recirculation system through which both parts can be managed separately in order to get optimum productivity.
“We wanted a warm water, fast-growing fish and opted for tilapia, the sixth most produced fish in the world. We chose tomatoes because they need more nutrients. If the system works with tomatoes, it will work with salad, vegetables, herbs and other hydroponic plants,” explained the project coordinator, Professor Werner Kloas.
The scientist explained that this new method consists of a closed recirculation system for the fish with optimum food conversion ratios and that then in the hydroponic part there is a reservoir of fish water, which has to be optimised for pH and supplemented with some nutrients.
“Other than that, there isn’t much manipulation because most of the nutrients are already in the fish water. This overcomes the shortcomings of a single circulatory system. We also regain evaporated water from the air conditioning system as well as collect rainwater. At a later stage we might even be able to use some of the water left over by our system instead of using freshwater from other sources,” pointed out the professor.
Kloas is convinced any type of fish or other aquatic animals can be produced, except shrimp because they do not give a lot of yield in volume: one cubic metre of water could produce 10-20 kg of shrimp at the most while it is possible to get 50 to 200 kg of fish.
In addition, using algae in place of hydroponic plants could open the way to farming marine water fish.
The professor commented that sizing options have been explored and have shown that this can both work in households, with units that cost under EUR 1,000, and be up scaled to obtain food security in really big systems.
The smallest viable production site would be about 5,000 square metres and several such sites linked together in one big greenhouse would be commercially viable. There are already a lot of greenhouses in places like the Netherlands and all they need to do is add aquaculture.
“Tomatofish is especially suited for developing countries with water scarcity but also to make large scale food production more sustainable,” claimed Kloas.
The next step is the installation of two of those smaller systems in a local school in Berlin and the school will be connected to #FarmedintheEU.
“The biology and chemistry teachers are very excited about this and they are doing some experimental aquaponics in the school with different plants and even different species of fish,” the professor stated.