Sustainable fish aquaculture
Aquaculture is globally the fastest growing food production sector (8.8 % yearly growth rate), but it is also linked to a number of environmental challenges. These include negative impact on water quality arising from fish effluent, the interaction with the natural populations, the use of wild fish population as fish feed as well as the amount of land, water and energy used.
Aquaculture in the Baltic Sea is almost exclusively based in Scandinavian countries. Contrary to global developments it is has constantly been on the decline from an already very low level representing only 0.1 % of world-wide aquaculture production (+6.9 % world-wide aquaculture growth since 2000 compared to -0.8 % BSR). This is due to limited amount of sites suitable for open net cage systems, which are still the predominant production technology, being the most cost-efficient (not accounting for environmental cost).
Innovative approaches are not only more sustainable, but also open the opportunity for the revival of this sector throughout the Baltic Sea Region. Land-based recirculating aquaculture systems (RAS) are expensive to build as well as to run, but offer numerous advantages: heating can come from biogas plants; nutrient rich effluent water can be treated or used as a resource for greenhouses; production is year round and can also be used for new species and/or restocking purposes and natural systems are not impacted. What is more: since RAS can be placed in areas unsuitable for open net cage systems they offer new market opportunities for Baltic Sea countries, which have no aquaculture sector so far. The technology, know-how and a variety of companies for RAS plant construction and operation are all in place within the region, with Denmark being the forerunner in this market.
The addition of integrated multi-trophic aquaculture (IMTA) to existing open net cages is yet another opportunity to reduce environmental impacts through direct uptake of dissolved nutrients, while at the same time increasing cost-efficiencies due to more products which can be sold. So far, however, hardly any real data or practical knowledge is available as only a few pilots exist in Finland and Denmark, where mussel or macroalgae cultivations are combined with open net cage fish farms.