Return of the Colchester native oyster

July 04, 2016 by Zoological Society of London


Conservation group marks major milestone in restoration project

More than 25,000 mature native oysters have been reintroduced to an Essex estuary by the Essex Native Oyster Restoration Initiative (ENORI) – in an attempt to restore a nationally important breeding population that once supported hundreds of fishermen.

The event is a milestone for ENORI – a coalition between international charity the Zoological Society of London (ZSL), oystermen and conservationists – and a significant step towards the restoration of Britain’s native oyster beds. Populations of the European native, or Colchester oyster (Ostrea edulis) are estimated to have been reduced by more than 95 per cent due to historic over-harvesting, disease, competition from invasive species and predators.

Oyster beds used to be an important structural and ecological component of Britain’s bays and estuaries, fuelling waterside economies for centuries and forming a ubiquitous part of our coastal culture. The popular shellfish are known as ‘ecosystem engineers’ because they facilitate the wider conditions for nature to thrive – stabilising shorelines, filtering water and providing vital food and habitat for coastal wildlife.

Commenting on the ENORI project, ZSL Conservation Programme Manager Alison Debney said: “Starting this brood stock of native oysters marks real progress in the recovery of one of Britain’s most valued and historically important marine species. Oyster beds have suffered from poor breeding success over the past few years, with this enhancement we are hoping to kick start the population again and pave the way for future restoration efforts and investment.

“Dredging is prohibited in the area for the next few years and will hopefully continue to be until oyster stocks are sufficiently recovered to begin sustainable harvesting.”

ENORI is a joint venture between ZSL, the Essex Wildlife Trust, Blackwater Oysterman’s Association, Blue Marine Foundation, Cambridge University, The Nature Conservancy, River Roach Oyster Company, Colchester Oyster Fishery, CEFAS, Natural England, the Environment Agency, and the Kent and Essex Inshore Fisheries Authority (KEIFCA).

Essex Wildlife Trust’s Living Seas Co-ordinator, Sarah Allison, said: “The Native Oyster is one of the UK’s rarest and most precious marine animals. Intrinsically linked to Essex, any loss of this iconic species would be felt far and wide, so it is great to be working on this ground-breaking project, which will hopefully begin the reversal of the oyster’s decline, with so many different partners.”

Essex Wildlife Trust staff, with the support of 30 volunteers, individually marked 2,500 of the oysters so they can track their progress, before they were relaid in the Blackwater, Crouch Roach and Colne Marine Conservation Zone (MCZ) in Essex on Monday 27 June. The area was designated by the government three years ago, following survey work by Essex Wildlife Trust, the Blackwater Oysterman’s Association and University of Essex, with the conservation objective to recover the native oyster and native oyster beds.

The ENORI project has been supported by Selfridges through its Project Ocean campaign, while the long term monitoring of the oysters will be supported by volunteer dive network Seasearch.

Image credit: ZSL


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