Complex coastal habitats such as reefs formed by the blue mussel Mytilus edulis provide a number of ecosystem functions to marine fauna, thus functioning as ecosystem engineers. Due to anthropogenic impacts including fishing and eutrophication, mussel reef distribution is decreasing in the Baltic Sea, indicating the need for evidence-based management strategies. The aims of this study were twofold: First, the ecological status of the study area was evaluated to assess whether it meets current European requirements set by the Water Framework Directive (WFD). Second, Baited Remote Underwater Video Systems (BRUVS) were used to investigate the mobile fauna diversity and species assemblage at mussel reefs compared to sandy bottom habitats. This thesis shows that despite poor ecological status the mobile fauna found in mussel reefs is extremely rich and unique, indicating their importance as diversity hotspots. Efforts to reduce eutrophication need to be increased and the capacity of natural mussel reefs to mitigate eutrophication needs to be further investigated. Further, Coastal conservation measures should be reconsidered to offer better protection to currently existing mussel reefs. In addition, future efforts should focus on large scale restoration of bivalve reefs to improve coastal habitats and their ecological status.
Keywords
Water Framework Directive ● Ecological Status Assessment ● BRUVS ● Bivalve Reef ● Ecosystem Services
