Thousands of oysters reintroduced to the Firth of Forth are thriving after being absent for over a century due to overfishing.

Marine experts from Heriot-Watt University, who helped release approximately 30,000 European flat oysters, report that underwater monitoring shows promising results.

Once home to one of the largest native European oyster reefs in the northeast Atlantic, the Firth of Forth yielded up to 30 million oysters annually in the 1800s. However, by the early 1900s, intense overfishing had driven the species to local extinction.

The ongoing Restoration Forth project, which also includes planting four hectares of seagrass, has achieved an 85% survival rate for the reintroduced oysters.

Naomi Arnold, the Restoration Forth project manager from WWF Scotland, said they were “delighted by the early signs of success”.

“This is down to the hard work of not only the staff involved but the hundreds of volunteers who have turned out in all weathers to help us prepare the oysters for deployment and to physically put them in the water,” she said. “This is a key milestone in our project. With this success and the amount we have learned, things are looking very positive for future restoration in the area.”

Since September last year, about 30,000 oysters have been reintroduced at four sites that are being regularly monitored. Edinburgh Shoreline, Fife Coast and Countryside Trust, the Marine Conservation Society, Project Seagrass and the WWF are all involved in the project.

Historically, oysters from the Firth of Forth were transported across the UK and Europe for consumption and to replenish other oyster beds. However, this overexploitation caused the collapse of local reefs, leading to the species’ disappearance from the estuary.

Naomi Kennon, a Heriot-Watt research associate for the project, said: “Over the next year we hope to see these oysters continue to thrive and to start to enhance the biodiversity on the seabed. Oysters enhance water quality through filter feeding, store carbon and enhance biodiversity by creating a complex habitat providing homes and shelter for countless other organisms.”

The project has also been a significant community effort, engaging the public through citizen science initiatives to raise awareness about the ecological importance of oysters.

Advocates highlight the role oysters play in improving water quality and supporting marine biodiversity, underscoring the broader environmental benefits of their return.

Anna Inman, a shellfish engagement officer at the Marine Conservation Society, said: “The community support for oyster restoration has been incredible. This achievement is a testament to the dedication of all the volunteers who have generously given their time.

“The project not only aims to revive marine life but also highlights the cultural heritage of oysters and emphasises our collective responsibility to restore and protect our seas for future generations.”

 

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