Restoration priorities in the North Sea
Written by Lauren Ackermans (Geographer with a heart for marine restoration)
The North Sea: rich but vulnerable
The Belgian part of the North Sea is small, but ecologically particularly valuable. It harbors more than 2,000 species. This is partly due to the variation in sandbanks, currents, tides, nutrients from the Scheldt, and diverse types of sediment. At the same time, this is a heavily visited area: fishing, sand and gravel extraction, shipping, and the production of renewable energy influence the marine environment. Due to this pressure, together with climate change and pollution, many ecosystems have been severely damaged. Protection alone is no longer sufficient. Restoration measures are therefore essential.
Nature restoration in action
To combat the ongoing degradation of marine habitats, the European Union adopted the Nature Restoration Regulation in June 2024. This obliges Member States to meet certain targets regarding the restoration of marine ecosystems. By 2030, EU countries must implement restoration measures on at least 20% of the sea surface. By 2050, all degraded ecosystems must be actively restored.
In 2022, researchers from the FPS Public Health – Marine Environment, the Institute of Natural Sciences, and various NGOs selected three priority forms of nature restoration in the Belgian North Sea, namely:
- Restoration of oyster banks
- Restoration of gravel beds
- Upgrading of other reefs, such as Lanice conchilega aggregations and Sabellaria reefs
Concrete main objectives have been established for these habitats:
- Reduce pressure on the system
- Increase knowledge about the ecosystem and potential restoration measures
- Implement active restoration measures
- Raise awareness among stakeholders and the general public
These priorities form the basis of the national nature restoration plan that Belgium is drawing up within the framework of the European Nature Restoration Regulation
Restoration of oyster reefs
Oyster banks are a top priority for nature restoration in the Belgian North Sea. As ecosystem engineers, oysters build reefs that provide food, shelter, and attachment sites for other species. In addition, they filter the water and store carbon and nitrogen. As a result, they contribute to climate regulation and the resilience of the ecosystem.
Natural recovery is often hampered by a lack of undisturbed hard substrate and seabed disturbance caused by fishing and anchoring. The BELREEFS project, the first offshore pilot project for flat oyster reefs in Belgian waters, addresses these challenges. In July 2025, more than 200,000 juvenile oysters (Ostrea edulis) were released 30 km off the coast, in a Natura 2000 area. Oyster larvae are released onto biodegradable substrates and placed on the seabed, while the development of the reefs and the increase in marine life are closely monitored.
Restoration of gravel beds
Approximately 16% of the Belgian seabed consists of hard substrates, the so-called gravel beds, ranging from gravel and pebbles to larger boulders. These stony reefs form valuable but vulnerable habitats where corals, aquatic polyps, and bryozoans build structures. Gravel beds provide shelter, nurseries, and food for crabs, fish, and other species, thereby increasing biodiversity. Many of these animals are important for fisheries but are also vulnerable to disturbance. Effective protection and restoration are crucial to preserve these unique habitats.
Upgrading of other reefs: Lanice conchilega aggregations and Sabellaria reefs
In addition to oyster banks and gravel beds, tube worm reefs also play an important role in the restoration of the North Sea. They function as ecosystem engineers: they build structures that hold sediment and stabilize the seabed, thereby limiting erosion caused by currents and wave action.
Sabellaria reefs form when millions of small polychaete worms each build a tube of sand grains and small shells, which offers them shelter and a place to live. The worms use a sticky mucus to glue the grains together. This creates a sturdy, solid reef in which numerous species, such as starfish, crabs, and fish, find food and protection.
Lanice conchilega aggregations form slightly different structures. Millions of sand tube worms build individual sand tubes that lie close together, thus forming dense fields or aggregations. These are less sturdy than Sabellaria reefs, but serve an important ecological function: the tubes slow down water flow, causing sand and organic material to settle. This stabilizes the seabed and increases food availability for other species. Through the upgrading of both types of reefs, habitat complexity increases and the North Sea becomes more resilient, contributing to the recovery of marine ecosystems and biodiversity.
Nature restoration in the North Sea by Go Ocean
Go Ocean is actively committed to the restoration of biodiversity in the North Sea by supporting, monitoring, and sharing innovative pilot projects with the general public. The restoration of these ecosystems is crucial for a resilient North Sea, sustainable fish stocks, and the preservation of ecological functions. Ongoing projects include:
- BELREEFS, restoration of flat oyster reefs (Belgium): European flat oyster reefs (Ostrea edulis) are being restored in the Belgian part of the North Sea. Before 1850, these reefs were a dominant structural feature of the North Sea, but due to human pressure and parasites, they have nearly disappeared. The oyster reefs are being restored as part of BELREEFS.
- Nature-inclusive harbour dam in Blankenberge (Belgium): This new harbour dam is partly constructed using nature-inclusive designed Haro blocks that stimulate biodiversity. Go Ocean tracks the effects on marine life and involves customers and stakeholders in monitoring and fundraising.
- Reintroduction of flat oysters in Borssele Wind Farms (Netherlands): This project uses innovative technology to place structures with adult oysters at a depth of 30 meters, allowing pilot sites to be tested and the effects on biodiversity to be monitored.
At Go Ocean, we believe that everyone can play a role in the recovery of the North Sea. By contributing to our projects, you contribute directly to the restoration of biodiversity, resilient ecosystems, and sustainable fish stocks. Together, we can scale up innovative solutions that help protect the seas of tomorrow. Join us in investing in the future of the North Sea: every contribution helps restore marine ecosystems and protect biodiversity.
Written by Lauren Ackermans
“I am a geographer driven by a strong passion for marine restoration. Ready to make a difference, I support Go Ocean in their mission to protect and restore our oceans and marine ecosystems.”
Sources:
Activiteiten op de Noordzee | FOD Volksgezondheid
BELREEFS: Herstel van oesterbanken in de Belgische Noordzee | Jan De Nul
Herstel van oesterbanken in de Noordzee | FOD Volksgezondheid
Mariene Strategie voor een duurzame en veerkrachtige Noordzee | Instituut voor Natuurwetenschappen
Natuurherstel in onze Noordzee | FOD Volksgezondheid
Ontdekking riffen bevestigt noodzaak bescherming Bruine Bank op de Noordzee – Stichting De Noordzee oesterriffen herstellen | FOD Volksgezondheid
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We are teaming up with four other Belgian impact organizations, because you cannot take systemic climate and biodiversity action alone, especially not in the ocean. Real impact only happens through collaboration.
Restoration priorities in the North Sea
The Belgian North Sea hosts over 2,000 species thanks to its rich ecological diversity. However, it faces serious threats, making active restoration essential.