Abstract
European flat oyster (Ostrea edulis) reefs formed extensive, biodiversity-rich habitats in the Belgian part of the North Sea until their collapse due to overfishing and disease. Within the Horizon Europe project BLUE CONNECT, an active restoration pilot is being implemented in the Vlaamse Banken Marine Protected Area, aiming to re-establish European flat oyster (Ostrea edulis) reefs where they historically occurred.
The Belgian demo site focuses on a carefully selected restoration location adjacent to a small shipwreck, situated within a marine reserve and Natura 2000 area. Site selection integrated historical oyster distribution data, high���resolution seabed substrate mapping, hydrodynamic assessments and extensive consultations with research, industry and governmental stakeholders. The restoration approach combines ecological realism with operational feasibility by using natural substrates that closely mimic native gravel beds of the Vlaamse Banken.
Certified Bonamia-free oyster larvae are remotely set on natural sedimentary rock substrates under controlled conditions before offshore deployment. Reef installation employs biodegradable bags and controlled drop���bag techniques, minimizing seabed disturbance.
An integrated monitoring framework accompanies the restoration, combining traditional diver-based surveys with innovative tools such as multibeam and side-scan sonar imaging and passive acoustic monitoring of reef soundscapes. In parallel, co-management principles are embedded through active stakeholder engagement, including local working groups and participatory tool validation.
This case study demonstrates how science-based site selection, restorative aquaculture, offshore engineering, innovative monitoring and stakeholder co-development can jointly support oyster reef restoration within marine protected areas, contributing to national and European restoration objectives.
Acknowledgment
This work was developed under the BLUE CONNECT project, financed by the European Union's Horizon Europe Research and Innovation Program under Grant Agreement no. 101156759. The authors would like to thank all members of the BLUE CONNECT Belgian Demosite for their contributions to the discussion and work that informed the development of this work.