UK’s first oyster restoration project aims to rebuild once thriving reefs off south coast of England

Oyster beds are among the world’s most imperilled habitats, with around 85 per cent of the total which were once abundant around the world having been destroyed by human activity.

In Europe, the species has been hit so hard it has almost become extinct, with declines of more than 90 per cent since the 19th century.

The loss of these ecosystems has the potential to be disastrous, as oysters filter the water column, removing nitrogen, sequestering carbon and providing habitats for hundreds of species. A single oyster is able to filter over 200 litres of water every day.

But now the UK’s first oyster restoration project aims to bring oysters back to the seabed in Langstone Harbour, near Portsmouth on the Hampshire coast.

The project, run by the Blue Marine Foundation and Portsmouth University, aims to transform marine biodiversity and water quality in the Solent - the strait which separates Hampshire and the Isle of Wight.

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The seabed here was once home to the largest oyster fishery in Europe, but over-fishing of the oysters, along with disease, pollution and the arrival of invasive species resulted in the collapse of the oyster population and the areas fishery, which closed in 2013.

The aim of the new hatchery is to provide a reliable source of native oysters and to enable their numbers to grow in the Solent, where they will help keep the water clean and provide food and build the ecosystems upon which many other marine species depend.

Jacob Kean-Hammerson, restoration projects manager at the Blue Marine Foundation, said: “The installation of this hatchery represents a step-change for the restoration of native oysters in the Solent and further afield.

“The oysters reared in this hatchery will be used to reseed the Solent for many years, scaling up restoration efforts and helping to see the previously abundant oyster populations flourish once more."

The hatchery will also allow further research into ensuring that the oysters are disease-resistant without any loss of genetic variation or adaptation to local environmental conditions.

Dr Joanne Preston, reader in marine ecology and evolution at the University of Portsmouth, said: "The biggest barrier to restoration of the native oyster, Ostrea edulis, is the lack of oysters, so we need to breed more oysters, but in a way that preserves genetic diversity, harnesses disease resistance, but doesn’t spread disease.

"We looked at hatcheries that have been instrumental to Ostrea species restoration success in the USA and Australia, and built on the UK’s heritage in shellfish production to develop a hatchery to enable us to scale up restoration in the Solent."

The University of Portsmouth said numerous restoration projects are taking place around Europe hoping to restore populations of the native oyster, but supply issues surrounding the lack of oysters that are biosecure, genetically diverse and locally adapted is the main limiting factor in almost every project.

It is hoped that the new hatchery will solve this problem in the Solent and could act as a blueprint for other restoration projects throughout Europe.

Additional reporting by PA.