A marine environment restoration project off the Yorkshire coast is testing an innovative new method of settling juvenile oysters into the sea.
Once home to vast natural oyster reefs covering over 300 acres, the mouth of the Humber where the estuary meets the North Sea, used to support a thriving population of native molluscs. The oysters farmed there became part of the staple diet for generations of people living nearby. However, historic overfishing, industrial pollution and disease almost completely destroyed the reefs during the last century leaving them unable to recover naturally.
Now the Wilder Humber seascape restoration partnership is trialling a new technique in which oyster larvae grown on scallop shells are being deployed directly onto the seabed to create ready-made reefs. The process will see the larvae and their host shells being bundled together in special mesh bags.
Wilder Humber oyster project
Until now, traditional restoration involves juvenile and adult oysters being placed onto stones, broken shells and grit on the seabed where they can spawn over time and eventually form a reef. However, this is not only costly and logistically challenging; it can also be stressful to oysters during transit, leading to lower survival rates.
The experiment is taking place at Yorkshire Wildlife Trust’s Spurn Point nature reserve and aims to find out whether the new method is the best way of reaching an ambitious target of reintroducing 500,000 oysters to the estuary over a five-year period.
Laura Welton, the trust’s native oyster restoration officer, said:
“Remote setting is an emerging technique with real and exciting potential to transform how we restore native oyster populations.
“It allows us to settle oyster larvae closer to where they will eventually live, reducing transportation stress and increasing their chances of survival. Trialling this alongside the traditional method gives us vital insights into how to scale up restoration more efficiently and effectively. This is a key step toward restoring thriving oyster reefs in the Humber, across the UK and beyond.”
Growing oyster larvae on scallop shells
Over the last 12 months, larvae initially grown at a hatchery in Scotland have been settled on scallop shells inside a series of tanks at the trust’s base at Spurn, before being attached to specially made trestles standing in shallow tidal waters off the peninsula.
In another first, the partnership is reintroducing a unique mix of oyster age classes, ranging from larvae on shells which are literally days old, to 11-year-old adults. By mixing age groups, it’s hoped a stronger, more resilient population will emerge that can reproduce sooner while being more resilient to disease.
As natural water filters, the oysters can help clean the sea by improving water clarity and reducing excess nutrients. When a reef forms, it also acts as nursery for another marine life while also creating a natural coastal defence to help reduce erosion and stabilise sediments.
Andy van der Shatte Olivier, the trust’s marine programme manager, said:
“Our Wilder Humber restoration programme is taking a truly pioneering step in the UK’s marine restoration journey. This project is not only bringing back a lost species but is also demonstrating how innovation, collaboration, and nature-based solutions can tackle two of the greatest environmental challenges of our time: biodiversity loss and climate change.
“By restoring oyster reefs, we are helping to store carbon, protect coastlines, and create thriving marine habitats.”
Wilder Humber is a major seascape restoration initiative delivered in partnership by Yorkshire Wildlife Trust, Lincolnshire Wildlife Trust, and energy company Ørsted.
