The cool new idea to bring back flat oysters to the North Sea
Thirty meters below the waters of the North Sea, a cargo ship sunk over a century ago has become the base for an unprecedented experiment. In early July 2025, a team of scientists deposited 200,000 larvae of European flat oysters on the hull of the Kilmore, a shipwreck off the coast of Belgium.
The goal is twofold: to recover an emblematic species that was on the brink of extinction and, at the same time, to use the wreck as a refuge for marine biodiversity. The idea is not just to repopulate, but to create a reef capable of sustaining itself over time.
Belreefs: Ecological Restoration and International Cooperation
Belreefs is not an isolated experiment, but the beginning of a long-term recovery plan. According to Vicky Stratigaki, project coordinator at the Belgian company Jan De Nul Group, the ambition is clear: to allow nature to regain control without the need for further human intervention.
Centuries-old shipwrecks in Belgian waters are legally protected as marine heritage sites, making them fishing-free zones and ideal environments for marine life to thrive. In this sense, the Kilmore is not just history, it is also the future: resting on gravel beds where oyster reefs once flourished.
The action, which has required years of preparation and coordination, could become a replicable model for other regions of the world where the loss of marine biodiversity is a growing threat.
European Flat Oysters: Ecosystem Engineers
European flat oysters are not simple mollusks: they are considered “ecosystem engineers.” Their shells provide shelter for fish, crustaceans, and algae, while performing vital functions such as water filtration, nitrogen fixation, and protecting the seabed from erosion.
Before the mid-19th century, they were abundant in the waters of northern Europe. However, overfishing, seabed degradation, and the arrival of the parasite Bonamia ostreae in 1979 pushed the species to the brink of extinction in the region.
The release of larvae aims to reverse this trend. Although it is estimated that only 15% will survive the first year, researchers are confident that those that do survive will form the basis of a self-sustaining reef.
Expectations and Future of the Project
The plan includes years of scientific monitoring. The survival of the oysters will be evaluated, as well as the chain effects on the biodiversity of the North Sea. The Belgian Minister of Justice, Annelies Verlinden, has emphasized the value of these initiatives, framing them within the national goal of ecologically restoring at least 20% of the sea by 2030.
If the experiment is successful, similar actions could be multiplied in other points along the Belgian coast and beyond, with the aspiration of recovering key species and restoring stability to ecosystems damaged by centuries of human activity.
The restoration of the Kilmore could be just the first step towards a new model of marine restoration in Europe, where history, science, and policy intertwine underwater.
