Towards environmentally friendly finfish farming: A potential for mussel farms to compensate fish farm effluents

Aquaculture is seen as a possible solution to meet the rising demand for fish but only if the sector reduces its use of wild fish in feed as well as its environmental impacts. The cultivation of extractive species along with fish farming (the integrated multi‐trophic aquaculture system) has a potential to mitigate the adverse environmental effects of fish farming. The dynamic energy budget (DEB) modelling is a powerful tool to be used in different aquaculture settings to achieve the Blue Growth goals set by the commission. This study explored the potential of mussel for bioremediation at finfish farms to develop environmentally sustainable finfish farming solutions in the eutrophic Baltic Sea region. The study integrated the DEB models of blue mussels Mytilus edulis/trossulus and rainbow trout Oncorhynchus mykiss and a regional hydrodynamic‐biogeochemical model to explore the potential of mussel farming to fully compensate nutrient discharges from finfish farms. The DEB models demonstrated that despite suboptimal mussel growth conditions (low salinity), mussel farming has a potential to fully compensate for the discharge of nutrients from fish farms and thereby provide a solution for sustainable fish farming in the Baltic Sea region. Synthesis and applications. As such fish farming may become a necessary enabler of economically sustainable mussel farming in the region. Mussel farming facilitates finfish farming licensing whereas finfish farming covers some costs of mussel farming thereby increasing the economic feasibility of this activity in the region. Fish farming may become a necessary enabler of economically sustainable mussel farming in the Baltic Sea region: Mussel farming facilitates finfish farming licensing whereas finfish farming covers some costs of mussel farming thereby increasing the economic feasibility of this activity in the region.