Work underway to create oyster sanctuary off the north Essex coast
PUBLISHED: 15:32 25 June 2019 | UPDATED: 15:47 25 June 2019
A coalition of scientists, conservationists and fishermen are working together to restore the UK's largest protected area for native oysters.
Members of the Essex Native Oyster Restoration Initiative (ENORI) are creating the region's first mother oyster sanctuary off Mersea Island - the only Marine Conservation Zone (MCZ) in England for native oysters.
Across the country, native oyster numbers have plummeted 95% over the past 200 years due to historic over-fishing, habitat loss, pollution and the introduction of diseases. Conservationists say human intervention is the only way to bring the population back from the brink.
ENORI - a joint venture led by The Zoological Society of London and including Essex Wildlife Trust, Blackwater Oysterman's Association, the University of Essex, and Natural England - has begun creating the habitat required for the mother oyster sanctuary, replenishing the estuary's lost oysters.
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Recycled oyster and cockle shells and stones - known as cultch - have been laid onto the estuary floor, as oysters need a hard surface to grow on, which is not naturally found on the muddy estuary beds in Essex. This is followed by adult females or 'mother oysters' being laid, which, when conditions are right, will spawn in the coming weeks, initiating the first stages of the native oyster's life cycle.
Dr Tom Cameron, from the School of Biological Sciences, said: "This is a nationally unique project, as around many UK coastlines native oysters are close to extinction and none have stocks of this endangered oyster in the numbers that can still be found in Essex.
"Our research shows they provide benefits to local biodiversity, providing habitat for other species such as edible crab, but it also shows they are declining and need active management to recover the habitats they would have once had throughout the MCZ to allow their distribution and numbers to increase."
Oyster farming has been recorded in Mersea since Roman times, with the shellfish forming a staple part of British diets throughout history. However, populations of the European native, or Colchester oyster have suffered dramatic declines in recent centuries.
ZSL's Senior Conservation Programme Manager for UK & Europe, Alison Debney, said: "It may not be glamorous work, but laying 'mother oysters' at the right time is vital to the success of the restoration programme, and therefore vital for the survival of this native British species. ENORI was founded in 2013 by the conservation coalition in an attempt to restore a nationally important breeding population that once supported hundreds of fishermen."