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The environmentally friendly Danish Model fish farms are to be expanded from the current freshwater farms to also include saltwater fish farms. This requires new technological solutions, which in itself could become something of an export bonanza, according to

Fish farming is currently one of the world's fastest growing food industries. Denmark has a long tradition for fish farming and today is among the world leaders in equipment for green production, thanks to the development of so-called Model fish farms.

The high-tech and environmentally friendly Model fish farms use water from boreholes, rather than from rivers, and are based on water recirculation technology. This means that the fish farm recycles more than 95 per cent of the water instead of merely letting it drain away into the water course.

Now DTU Aqua and several of the key players in the industry are joining forces to take Danish fish farming one stage further. In order to put large rainbow trout and salmon on the menu as well, the technology from Model fish farms are to be expanded to include the breeding of saltwater fish as well as freshwater fish – and it is to take place inland. The project is being supported by the Ministry of Food, Agriculture and Fisheries’ Green Development and Demonstration Programme (GUDP).

"The global salmon market is huge. The production of fish in the aquaculture industry is increasing in several countries, but so far Denmark has not increased production significantly, mainly because of environmental restrictions,. But why should others produce our salmon if we can do it just as well - and without compromising the environment?" asks technical project manager Per Bovbjerg Pedersen from DTU Aqua in Hirtshals.

More fish, less pollution

In order to increase production in a sustainable and profitable manner, we need cross-disciplinary collaboration on new technological solutions for breeding fish in seawater to complement those solutions that DTU Aqua has already helped to develop within the field of freshwater fish farming.

"The goal is to produce more fish, but with the same or even lower emissions of nitrogen into the environment. This will be done partly through applying a known technique from freshwater farming, whereby bio-filters are used to convert the ammonia excreted by the fish into nitrate. Now the goal is to develop the technology further to do the same with seawater but also included denitrification, in order to convert this nitrate into nitrogen which can be released as a harmless gas. In this way the nitrogen is removed safely from the water," explains Per Bovbjerg Pedersen.

In a four-year project supported by the Ministry of Food, Agriculture and Fisheries’ Green Development and Demonstration Programme (GUDP), DTU Aqua, in collaboration with key industry players, is to develop technology to enable large rainbow trout to be farmed inland in seawater. After two years, the project will be expanded to test the feasibility of farming Atlantic salmon in inland saltwater fish farms.

DTU Aqua is responsible for the professional management of the project, in particular the environmental impact, water quality parameters and the development and optimization of cleaning technologies. The work is being carried out at the North Sea Science Park in Hirtshals in collaboration with representatives from all relevant parts of industry including the wellknown system suppliers Billund Aquaculture Service, the leading Danish fish feed producer Biomar and the largest farming, processing and sales company AquaPri.

The goal in the long term is not only to create a basis for an increased Danish production and export of sustainably produced saltwater fish: the actual technology in itself will have equally strong export potential, Per Bovbjerg believes.

"Denmark is already a world leader in water recirculation technology and Model fish farms, thanks to our unique composition of components drawn from our experience in water recirculation techniques. The aim is to further exploit and expand the Danish position in the field of water recirculation by combining it with farming techniques, equipment and complete plant solutions for saltwater fish farming," says the technical project manager from DTU Aqua.

March 2011

the Fish Site Editor

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