Native Oyster Bed Potential (EA)

Published by the Environment Agency the Native Oyster Bed Potential areas are derived from seabed sediment and current energy criteria. The Native Oyster Bed Potential Area layer provides a national ‘high level’ indication of where native oyster reefs could potentially be restored based on some key environmental variables. It should be considered as an initial aid to identifying sites. The areas identified are based on outputs from large scale models and should not always be assumed to be precise at the local level. The location of significant activities (such as dredging), marine assets (such as submarine cables) and ecological risks (such as disease control areas), which could restrain a location’s potential, have not been factored in in the creation of this layer. The presence of such activities and structures should of course be considered at an early stage before making any local selection of suitable sites. It should not be assumed that all the areas identified meet all environmental conditions required to re-establish native oyster bed habitat, or that native oysters only currently exist within these areas. Instead it aims to provide an initial attempt to identify potential areas at a national level. Furthermore, it is probable that there are some areas outside the areas identified that could be suitable for restoration. Dataset Description Native oyster bed potential areas were primarily derived from the EMODnet 2016 current energy models, the Natural England Marine Habitats and Species Open Data and a portion of the JNCC EUNIS Level 3 seabed habitat map integrating data originating from maps and field surveys and the EUSeaMap model v8.3. These datasets were combined to determine potential native oyster bed habitat areas. Selection Criteria used habitat preferences for Ostrea edulis identified by the Marine Life Information Network (MarLIN) as follows: Current = Low Energy, <130 Nm-2, (mean of annual 90th percentile values over six years) Broadscale Habitat Type = Subtidal mixed sediments (EUNIS Level 3 = A5.4) These criteria produced an area, which was refined further using an Environment Agency intertidal layer to ensure all intertidal areas were excluded. The area was also clipped to within Wafer Framework Directive water body boundaries (typically within 1 nautical mile of coastline). Some further areas were removed based on expert judgement and their close proximity to major ports. Finally, each polygon was assigned a water body and river basin district based on the WFD cycle2 Transitional and Coastal Water Body layer. More information is available HERE.