Groundbreaking project reintroduces native oysters into Humber Estuary

A groundbreaking restoration project, Wilder Humber - a collaboration between Yorkshire Wildlife Trust, Lincolnshire Wildlife Trust and Ørsted - is making waves by trialling remote setting, an innovative restoration method never before used to restore native European flat oysters, Ostrea edulis, in the UK.

The Humber estuary was once teeming with a thriving population of European flat oysters with historical records suggesting that one such oyster reef covered over 300 acres of the foreshore. However, these once-abundant reefs were decimated due to historical overfishing, poor water quality and disease. Today, the once-mighty native oyster populations along UK coasts are fragmented and depleted, too isolated to naturally recover.

The restoration and preservation of oyster reefs are crucial for maintaining robust, resilient marine and estuarine ecosystems. Oyster reefs play a pivotal role in supporting the marine environment, offering a host of significant benefits.

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The oysters themselves serve as potent water filters, aiding in maintaining cleaner seas by enhancing water clarity and reducing surplus nutrients. As oyster reefs establish, they create vital nursery habitats, providing refuge and breeding grounds for a broad variety of marine species.

Beyond their support for wildlife, oysters reefs benefit coastal communities by acting as living breakwaters, diminishing wave energy, stabilising sediments and assisting in protecting coastlines from erosion.

Wilder Humber, launched in spring 2023, is joining forces with The Nature Conservancy and The Oyster Restoration Company to reintroduce half a million oysters into the Humber estuary over a span of five years, marking an important stride towards revitalising the Humber's native oyster population. Typically, native oyster restoration involves buying juvenile and adult oysters to be placed directly onto the seabed.

However, this method can induce transportation stress on the oysters, incur high costs, impact the donor stocks and often results in low survival rates. This initiative signifies the first trial of using remote setting to reintroduce native oysters in the UK, laying the groundwork for innovative restoration practices.

Dr. Nik Sachlikidis, CEO of The Oyster Restoration Company, said: "The Oyster Restoration Company is excited to join forces with Yorkshire Wildlife Trust and The Nature Conservancy in this groundbreaking project, the first of its kind in the UK."

“By collaborating with knowledgeable and mission-aligned partners, we are taking a major step towards scalable onshore and offshore deployment that will significantly enhance biodiversity. The positive impact of native oysters on marine ecology is profound, and together, we are paving the way for further native oyster restoration projects, ensuring a healthier and more resilient environment for the future.”

This unique collaboration will involve adult oysters being spawned at The Oyster Restoration Company hatchery in north-west Scotland, producing millions of tiny larvae. These larvae will then be carefully transported to Spurn Point National Nature Reserve, where they will be introduced into a tank filled with scallop shells.

Over a period of three days, they will settle on the shells and become permanently attached. The shells, now home to the attached larvae, will be kept in the oyster nursery at Spurn Point, where the restoration team will monitor their growth and development until they are ready to be released into the Humber estuary.

Laura Welton, Native Oyster Restoration Officer at Yorkshire Wildlife Trust, said: “Remote setting is beneficial because it allows the seeded oysters to be produced closer to where they will eventually grow, improving acclimatisation, reducing transportation stress, improving the chances of successful oyster cultivation, and reducing costs.

“We hope to see a high number of oyster larvae settled on the scallop shells. If the trial is successful, this method has substantial potential for creating larger native oysters reefs in the Humber and around the UK.”

Boze Hancock, from The Nature Conservancy, added: “While remote setting is only one tool to help the restoration of a critical habitat in the North Sea and surrounding waters, it has proved to be powerful in enabling restoration at scale.

“From the US to Hong Kong and Australia it is a tool that has really helped restore oyster reefs and it will help the work in the Humber estuary. Beyond the Humber, the technique will be essential for integrating oyster restoration into the construction of offshore wind in the North Sea. So this demonstration is an important step in our ability to restore the function of our marine ecosystem regionally.”

Samir Whitaker, Biodiversity Lead Specialist at Ørsted, expressed his enthusiasm for the project, saying: “We are excited to be part of Wilder Humber, through which we are taking action to tackle two urgent challenges that are too often addressed separately: halting and reversing biodiversity loss and preventing catastrophic climate change.

“Restoring our lost marine ecosystems, at scale, is one of the best approaches we have to storing carbon as well as providing vital habitat such as oyster reefs which support numerous other species."