This PhD study aims to investigate specific ecological interactions in order to provide information on how marine protection, i.c. reducing or excluding fisheries impact, impacts the ecosystem functioning as well as how the higher trophic levels are influenced. The study is performed along the coast of the Belgian Continental Shelf and on the Flemish beaches. The presence of the sandmason Lanice conchilega provides habitat complexity. This polychaet occurs in very high densities (3000 ind/m≤). The tubes create a micro-environment in which suspended material is trapped. In this way ëtubereefsí develop. The impact of beam trawl fisheries on this habitat will be investigated in different disturb experiments. The dispersion of the subtidal reefs can be analysed through side scan sonar imagery. The ecological interactions with sole Solea solea will be investigated through stomach analyses. The stomach contents of sole foraging near Lanice reefs and sole further off those reefs will be compared. Sole will be caught with special designed drift nets. The quantitative data of this research will be integrated in a decision support system through the StellaÆ software.