Over the past five years there has been increasing concern around the spread of wild Pacific oysters in Marine Protected Areas. In Devon and Cornwall, the abundance of Pacific oyster Magallana gigas (formerly Crassostrea gigas) within intertidal Marine Protected Areas has led to some sites being reported as being in unfavourable condition. Natural England, in partnership with South Devon Area of Outstanding Natural Beauty Estuaries Partnership and Cornwall Wildlife Trust, with funding from the European Maritime and Fisheries Fund, undertook an investigation into monitoring and control measures for Pacific oysters within Marine Protected Areas.
Between 2017 and 2020, volunteers led by Cornwall Wildlife Trust and South Devon AONB Estuaries Partnership, conducted surveys around Cornwall and South Devon, to record the density of Pacific oyster populations and to test the effectiveness of culling as a method of controlling population expansion.