Oyster farming has been recorded in Mersea since Roman times, with the shellfish forming a staple part of British diets. However, the once abundant European native flat oyster - Ostrea edulis - has suffered a 95% decline in population in the last 200 years due to overfishing, habitat loss, pollution and disease.
Although the value of the Colne estuary oyster population was recognised by King Richard I in 1189 – who granted the oyster fishery to the Borough of Colchester – little was known about the state of the oyster populations within the Blackwater, Crouch, Roach and Colne estuaries or the wider Essex coastline today.
What we did
We demonstrated that the Essex estuaries were a stronghold for the European native flat oyster in the southern North Sea.
Our marine biologists worked with the Essex Wildlife Trust to assess the distribution of this species that provided key evidence for DEFRA to establish the first Marine Conservation Zone (MCZ) for native oysters and the recovery of their habitats - the Blackwater, Crouch, Roach and Colne estuaries MCZ (BCRC MCZ) in 2013.
We found that despite their success in Essex, natural replenishment of their local populations had stalled and that recruitment was best where active intervention was being undertaken by oystermen.
Since then and working with the Kent and Essex Inshore Fisheries and Conservation Authority (KEIFCA) our biologists estimated the abundance of native oysters remaining in the MCZ, the survival and growth of native oysters and how this affects population trends, assessed the benefits native oysters bring to coastal seas and produced working models of native oyster populations within this protected area so restoration work could be undertaken effectively.
Our research, therefore, set a clear baseline for future management and restoration of the native oyster.