The first 15,000 horse mussels have been placed on the seabed of the Dogger Bank as part of an ambitious effort to restore its lost shellfish reefs.
The work is an important milestone for the ELSP-supported Dogger Bank restoration project, led by the Doggerland Foundation. During an expedition with ARK Rewilding Netherlands, Blue Marine Foundation and Atlantic Technological University, the team placed horse mussels at four locations using several different methods.
Over the coming years, the trial sites will be monitored to determine whether the mussels survive, reproduce and begin forming new reefs. The findings will inform plans to expand horse mussel restoration across the Dogger Bank.
Restoring reefs on the Dogger Bank
Spanning approximately 2.5 million hectares across UK, Dutch, German and Danish waters, the Dogger Bank is one of the most productive areas of the North Sea. Its shallow waters provide important spawning, nursery and feeding grounds for fish, marine mammals and seabirds.
Centuries of bottom trawling and other pressures have severely degraded its seabed habitats, including the shellfish reefs that once supported diverse marine life. The Dogger Bank project is combining habitat restoration, legal action and public engagement to support the seascape’s long-term recovery.
Emilie Reuchlin, Director of the Doggerland Foundation, said: “We have been conducting ecological research into restoration possibilities for years. With the release of 15,000 horse mussels, we can observe what these shellfish actually need to form reefs. This experiment is a first step towards scaling up in the coming years.”
Testing restoration methods
The mussels were placed at four sites in steel cages, cotton bags and loose on the seabed. Comparing these methods will help the team understand which conditions give the mussels the best chance of becoming established.
The trial builds on experience gained through oyster reef restoration but applies it to horse mussels in the challenging conditions of the open North Sea.
“We have experience with oyster reef restoration, but for the first time in the North Sea, we are going to attempt to restore horse mussel reefs,” Reuchlin said. “If these horse mussels can survive and reproduce here, the future prospect of a healthy Dogger Bank with a rich and vibrant seabed comes back into view after centuries of decline.”
Ecosystem builders
Horse mussels are native to the Dogger Bank and can form extensive reefs when conditions allow. Their shells create complex structures that provide places for other animals to live, shelter, feed and reproduce.
Roos Bol of ARK Rewilding Netherlands said: “The horse mussel is a true ecosystem builder. Under the right conditions, they build new reefs shell upon shell, containing all kinds of crevices, nooks and crannies: perfect for various animal species to live in, shelter, lay eggs on and feed.”
The mussels also filter particles from the water and can help to stabilise the sediment around their reefs.
The project team will return to the trial sites in spring to assess how the mussels have become established. Monitoring will continue over the coming years, providing evidence to guide the potential restoration of horse mussel reefs at a much larger scale.
This restoration activity is supported by the European Union through NextGenerationEU and the Netherlands Ministry of Agriculture, Fisheries, Food Security and Nature.
This article was originally posted on the Doggerland Foundation website.
