Large areas in the Wadden Sea are closed for bottom fishery (mussels and shrimps). The goal of this closure is to promote the development of natural subtidal shellfish beds and enhance the natural values. In order to evaluate the effectiveness of this closure, the development of shellfishbeds in areas that are closed for fishery will be compared to areas that are open for fishery. The shellfish and associated species will be sampled by a suction dredge. Additionally, the long-term dataset of IMARES monitoring in the Wadden Sea will be analysed on non-target species. The project will run from 2015 to 2017.