ENVIRONMENT IN-DEPTH Restoration Forth
Restoring the Forth, one oyster at a time
Heriot-Watt University, alongside charity and scientific partners, has returned 60,000 oysters to waters that were once home to one of the largest oyster beds in Europe. The transformative project is redefining what it means for a community to participate in science.
At their peak, the oyster beds of the Firth of Forth stretched 20 miles long and six miles wide, yielding up to 30 million oysters a year at the height of harvesting. They sustained coastal communities, fed cities and exported stock across Europe. But, by the beginning of the twentieth century, overfishing had reduced them to local extinction. The water remained but the oysters were gone and, with them, their environmental benefits.
Globally, around 85% of the world's oyster reefs have been lost.
Globally, around 85 per cent of the world's oyster reefs have been lost. The Firth of Forth was part of a much larger ecological collapse. Heriot-Watt had spent years building the knowledge and methodology to change that.
Heriot-Watt is working alongside a range of partners including WWF, Marine Conservation Society, Project Seagrass, Balanced Horizons and many others. The project launched in 2022 with a target of returning 30,000 European flat oysters to the Firth by 2024. In March 2026, the joint team announced it had reached 60,000, more than double that original ambition.
Taking learnings from its other restoration sites, Heriot-Watt's research team developed a site selection model to identify areas with the greatest potential to sustain oyster populations. Mapping the seabed across the entire Firth meant tracking depth, substrate and human activity data. The model identified both intertidal and subtidal sites that have underpinned the project's impressive results.
The project launched in 2022 with a target of returning 30,000 European flat oysters to the Firth by 2024. In March 2026, the joint team announced it had reached 60,000, more than double that original ambition.
Between launch and September 2024, 420 people conducted 130 surveys, recording nearly 4,000 shells and generating data now being used by the Heriot-Watt team.
Monitoring by the university's scientific dive team in late 2025 showed an average survival rate of around 88 per cent for oysters deployed from boats, among the highest figures recorded by any comparable project. The team's own research attributes this directly to the care taken with the site selection work.
While Restoration Forth has started to change what lives in the Firth of Forth, it’s also changing who feels responsible for it. A citizen science programme, developed through structured community consultation and with the Marine Conservation Society, launched in 2024 creating four distinct survey activities pitched at different levels of commitment and expertise.
Volunteers conduct habitat surveys recording substrate types that feed into site suitability models. They also run oyster observation guides to map the historic presence of shells around the Firth, under the expert guidance of the research team. From biodiversity surveys at deployment sites to assisting with monitoring of oyster survivability and growth in intertidal experiments, citizen scientists have been at the core of the project’s success.
Between launch and September 2024, 420 people conducted 130 surveys, recording nearly 4,000 shells and generating data now being used by the Heriot-Watt team. Over 230 community members attended training events in that period, working alongside students and academics.
More than
community members attended citizen science training events
The Heart of Newhaven Community volunteers cutting a ribbon to unveil a mural celebrating the Restoration Forth project.
Oyster deployment with Edinburgh & Lothians Regional Equality Council volunteers. ©Maverick Photo Agency.
The methods developed at Restoration Forth are already being adopted beyond the Firth of Forth. Restoration projects in the Moray Firth and Cromarty areas are applying the same citizen science approach while the project team shares learning through the Native Oyster Restoration Alliance, a pan-European network of over 50 active restoration sites.
Hundreds of volunteers have carefully cleaned and prepared oysters under strict biosecurity protocols before every deployment, an activity which has brought diverse groups of people together. Volunteers include recent arrivals to Scotland, a deaf-led group that has worked to develop British Sign Language signs for marine species, corporate businesses, those with long-term illnesses and even families with a direct ancestral connection to the Forth’s commercial oyster trade.
The Scottish Parliament recognised the project's vital contribution, noting the vital role that oysters play in laying the groundwork for a healthier marine ecosystem and a brighter future for Scotland’s seas. Each European flat oyster filters approximately 200 litres of water per day while locking carbon into its shell throughout its lifetime, making a restored oyster bed a living carbon store as well as a thriving habitat. The research team expects biodiversity at established sites to double over the coming decade as the oyster population matures.
The project's next phase centres on a dedicated hatchery at North Berwick, developed with Heriot-Watt's academic support. The hatchery will supply oysters at the volume needed to move from a proof-of-concept restoration into something approaching the ecosystem scale that the original Forth beds once represented. Hundreds of thousands of oysters, eventually millions, is the ambition.
A century of absence is ending. The oysters are returning to the Firth of Forth and the communities that once built their lives around them are finding their way back too. What overfishing and pollution took generations to destroy, patient science and thousands of volunteer hours are beginning to reverse. The 60,000 oysters now beginning to filter the waters of the Firth are not just an ecological milestone. They are proof that what is lost is not always gone forever.
Each European flat oyster filters approximately 200 litres of water per day while locking carbon into its shell throughout its life.
Partners include WWF, Marine Conservation Society, Edinburgh Shoreline, Fife Coast & Countryside Trust, Project Seagrass, Royal Botanic Garden Edinburgh, Scottish Seabird Centre, The Ecology Centre, Balanced Horizons and The Heart of Newhaven Community.
The project has been made possible by funding from Aviva, the ScottishPower Foundation and the Moondance Foundation; additionally, this project is supported by the Scottish Government's Nature Restoration Fund, which is facilitated by the Scottish Marine Environmental Enhancement Fund (SMEEF) and managed by NatureScot.
The current phase of Restoration Forth is made possible by funding from Sky and the Cinven Foundation; the project is supported by the Scottish Government’s Nature Restoration Fund, managed by NatureScot.
