The effect of bottom trawling on Baltic Sea seabeds is poorly understood. Evidence from other seas shows that benthic fauna and sediments may be severely disturbed by this fishing method. Suspended sediment can also increase turbidity and be transported by currents into other less disturbed areas. In the southern Baltic, where there is intensive bottom trawling for cod, there is a risk that trawl-suspended sediment could drift into cod spawning areas at a sensitive time of this species’ life cycle. Suspended sediment could also potentially affect marine protected areas (MPAs). However, this has not been quantified, despite this information being essential in the effective planning of MPAs, ecosystem-based sustainable fisheries management and assessment of seafloor integrity and ecological status of benthic ecosystems in the Baltic Sea. This project will: a) quantify how seafloor integrity is altered by bottom trawling; b) quantify the amount of sediment, nutrients and contaminants suspended by bottom trawling; c) quantify and model the distance suspended sediment is transported before settling; d) provide concrete recommendations to managers and policy makers on the optimisation of marine protected areas and fisheries closed areas. These questions will be addressed by field measurements of the extent and effects of experimental and commercial trawling (using state-of-the-art acoustic methods), modelling of the spread of sediment suspended by trawling, and lab experiments.