Areas likely to be unsuitable for Native Oyster
Native oyster beds were once widespread. Dense beds of oysters once formed reefs that stabilised the underlying sediments and provided a hard substrate for a range of other animals such as sea squirts, sponges, sea slugs and small seaweeds. They are now considered to be nationally rare with only scattered occurrences on the west coast, most notably lochs Ryan, Sween and Scridain.
There is growing interest in restoring native oyster beds in Scotland.
Marine Directorate undertook an analysis to identify areas that are likely to be unsuitable habitat for native oyster restoration.
The layers show areas that are likely to be unsuitable for native oyster based on thresholds of environmental variables. The environmental variables included are considered to be important for the survival and reproduction of native oyster. Conditions considered unsuitable are:
-
Depth > 80 m
-
Current speed > 0.45 m s-1
-
Silt content of the substrate > 75%
Two different temperature thresholds were considered unsuitable to reflect variation in spawning requirements of different populations of native oyster.
-
Maximum temperature <13°C
-
Maximum temperature <15°C
The analysis was done for the whole of Scotland at a resolution of 1 km and for the Orkney region at a higher spatial resolution.
Data originators:
Scottish Government (Marine Directorate)
More information: Mapping areas likely to be unsuitable for Native Oyster (Ostrea edulis) restoration at two spatial scales
