As the demand for fish continues to grow, aquaculture production must increase to maintain the availability of seafood supply and reduce fishing pressure. The way to meet the demand is to farm fish. Fish meal is the dominant protein source in fish feed, but its production is decreasing since better direct utilisation of pelagic fish into more valuable human food products is envisaged with better techniques in fishing and chilling of the raw materials.
At Matís, dr. Ragnar Jóhannsson, project group leader, has worked on various projects aimed at finding alternative feed for aquaculture and taking advantage of unused raw materials. Waste from cellulose factories in Sweden and microbial biomass grown in geothermal gases from Hellisheidi Geothermal Plant are potential sources for future aquaculture feed.
Ragnar has been working with Swedish companies on a project to produce Single Cell Protein (SCP) from forest industry side streams. The project’s main aim is to develop a replacement product for fish meal. The trick was to choose the best-suited microorganisms and the side streams in the cellulose and paper industry best suited for the production of SCP. The protein mass is dried and mixed with other raw materials, replacing fish meal in the formulation. This feed was first tested on tilapia and gave good results as a very good protein source. Now another project is in progress to develop feed for Arctic char.
Another method for producing aquaculture feed is to use hydrogen sulphide from Hellisheidi Geothermal Plant that can act as an energy source for specific bacteria. The bacteria grow rapidly in the hydrogen sulphide and are then dried and mixed with aquaculture feed. This project was recently completed after two years of research, but further research is needed to optimize the results.