Species point records from 1993 MNCR Shetland Braer oil spill survey

Littoral and Sublittoral field surveys were carried out between 25 February and 2 March 1993 around the vicinity of the Braer oil tanker grounding. The aim was to provide a rapid assesment of the oil's impact on the marine benthos of the area with a view to suggesting where future work should be carried out. Nine sublittoral and 14 littoral sites were surveyed using standard MNCR techniques, with additional attention being paid to recording noticeable effects from oil pollution, absence of species which would be expected in particular habitats, fish numbers, and collection of sediment biota for possible hydrocarbon analysis by SOAFD. The effects of the oil spill on the littoral biota appeared very limited in geographical extent, with minimal noticeable difference to expected rocky shore community structure beyond 4 Km of the wreck site. The littoral zone of Garths Ness itself was the most heavily impacted as would be expected, with a high mortality of patellid limpets and littorinids. To the east, in Bay of Quendale, obvious effects were more limited, though there appeared still to be a reduction in the numbers of Patella vulgata and littorinids. Littoral algae and lichens appear unnaffected, with no visible signs of damage such as bleaching. Littoral sediments close to the wreck site occur only in the Bay of Quendale, where extreme sediment mobility results in a very impoverished Crustacean-Polychaete community (Howson 1988). Samples collected from these sediments indicated an absence of any biota. Sublittoral surveys on rock and sediment indicated variation in the extent of damage. Rocky sublittoral areas surveyed within 4 Km of the wreck showed no obvious signs of damage. There was a noticeable absence of fish species but whether this is attributable to the oil spill is not clear. Other elements of the biota appeared to be unnafected, with numerous urchins grazing coralline algae encrusted bedrock, and a sparse kelp zone showing no signs of bleaching. In the same vicinity however, sublittoral sediments showed gross effects, with major mortality of bivalves such as Ensis sp. and Spisula solida, and no other biota observed. This gross effect on sediment biota was still apparent in West Voe, some 20 Km north of the wreck, but was not noted in sites further north towards the head of Clift sound.