THE IMPACT OF THE SEA EMPRESS OIL SPILL ON BIRDS OF THE PEMBROKESHIRE COAST AND ISLANDS

ABSTRACT

Much of the Pembrokeshire coast and islands, together with its inshore waters, are of international importance for their breeding seabirds and wintering seaduck. Although the Sea Empress oil spill occurred before the breeding season, some 7000 oiled birds were recovered dead or alive. The impact of the oil spill on birds can be classified as follows: immediate mortality especially of more than 4500 wintering common scoter in Carmarthen Bay; sublethal effects on productivity of colonies and reduced adult survival from oil or dispersant ingestion; and chronic effects on bird populations from long-term pollution, particularly of prey. A range of monitoring and research projects are under way to investigate the impact, but it is premature to provide many results. The oil spill probably caused significant local declines in seabird colony sizes, especially of guillemot. The impact on common scoter will prove difficult to determine because of the poor quality and high variability of preincident data. Large numbers of oiled birds, particularly common scoter, were treated and subsequently released. The successful rehabilitation of such released birds is controversial; research and review results will be reported.