A project to return native oysters to the UK in a bid to improve the health of coastal waters will start thousands of the shellfish growing beneath harbour pontoons.
Ecologists consider oysters to be “ocean superheroes” for their ability to filter sediment, nitrates and other pollutants from the seas.
Nitrate-based fertilisers can end up in the sea as a result of run-off from farm land or sewage spills, causing algal blooms that deprive the water of vital oxygen.
A mature oyster can filter up to 200 litres of water a day, but native oysters are on the brink of extinction, with numbers declining 95% since the 1800s.
Around 4,000 mature oysters will be installed in six harbours across the North East of England, Wales and Scotland as part of the Wild Oyster Project.
Launched by the Zoological Society of London (ZSL), the Blue Marine Foundation (Blue) and trade association British Marine, it is hoped the oyster beds will become the “maternity ward” to the next generation of shellfish.
The project received a £1.2 million grant from the People’s Postcode Lottery’s Dream Trust.
So far, 47 nurseries with 1,300 oysters have been installed underneath pontoons in Sunderland Marina and Port of Blyth.
The mature oysters should begin reproducing over the spring and summer, releasing millions of larvae into the ocean that will eventually settle on rocks and other hard structures and begin to grow.
As well as Tyne and Wear, oysters will be placed in the River Conwy in Wales, and the Firth of Clyde in Scotland.
Celine Gamble, wild oysters project manager at ZSL, said: “The oysters will almost immediately begin their important work helping to create cleaner water and increase marine biodiversity in the UK.”
The nurseries are also intended to act as an outdoor classroom for schools and communities, and will be stewarded by local project officers.
James Scott-Anderson, environment executive of British Marine, said: “It is essential that we allow nature the space to recover and grow once again.
“Using marinas to house oyster nurseries is an innovative use of the space we have available.”
Blue’s senior UK projects manager Morven Robertson said: “It is vital in the current climate emergency and biodiversity crisis that nature receives the help it needs to bounce back.
“The Wild Oysters project will give the marine environment a chance to recover, which is not only important for nature and climate, but also the people that rely on it.”
Elsewhere, the UK’s first oyster restoration hatchery opened in Langstone Harbour near Portsmouth in Hampshire earlier this week.
Launched by the University of Portsmouth and Blue, it aims to provide a million oysters a year to restore an industry that collapsed almost a decade ago.
The oyster fishery in the Solent was once the largest in Europe, but a combination of over-extraction, disease, pollution and invasive species pushed it to the brink and the fishery eventually closed in 2013.
The new hatchery is also expected to transform marine biodiversity and water quality in the Solent.