Overview of the Environmental Effects
The grounding of the Sea Empress in February 1996 caused one of the largest and most environmentally damaging oil spills in European history. About 72,000 tonnes of crude oil were released into the seas around the coast of South-West Wales, a region renowned for the beauty and diversity of its coastline.
More than 100 km of outstanding coastline became seriously polluted by oil. Ecosystems of conservation, fishery and recreational importance were affected. A massive clean-up operation was launched, both at sea and onshore.
The Pembrokeshire coastline boasts National Park status and numerous other conservation designations. It has also been one of the best studied coastlines in North-West Europe, providing an unusually good baseline of information against which to gauge oil spill impacts. Scientists from various organizations participated in a major monitoring programme to study the effects of the spill on the coastal environment and wildlife. An independent group, the Sea Empress Environmental Evaluation Committee (SEEEC), was set up by the government to evaluate the results of more than 100 scientific studies. SEEEC organized a scientific conference on the environmental impacts of the oil spill (February 1998, Cardiff, Wales), during which the final SEEEC report was launched. The conference proceedings were also published in 1998. A number of other scientific reports and papers describing the impacts of the oil spill have also been published, and more are in preparation.
The pollution was at its height during late February and early March of 1996 at which time huge slicks were at sea, and many shores were experiencing large-scale bulk oil pollution. By April, as a result of natural dispersion and the clean-up operation, little bulk oil remained at sea and many shores had regained a semblance of normality. Wave-exposed rocky shores improved quickly through natural cleansing, followed by the intensively-cleaned sands of the main bathing beaches, most of which were reopened for Easter. However, many shores were affected by residual oil pollution through the summer of 1996. Contamination persisted out of sight within shingle, sands and muds and within surviving wildlife. Autumnal storms remobilized buried oil, causing the temporary reappearance of sheens and tar balls on many beaches. This storm action accelerated the natural cleansing of the coast. By spring of 1997, few shores showed visible evidence of oiling.
As for wildlife impacts, birds at sea were hit hard during the early weeks of the spill, resulting in thousands of casualties. In contrast, the grey seal population appeared little affected and impacts to subtidal wildlife were limited. However, much damage was caused to shorelines affected by bulk oil. Shore seaweeds and invertebrates were killed in large quantities. Mass strandings of cockles and other shellfish occurred on sandy beaches. Rock pool fish were also affected. However, a range of tough shore species were seen to survive exposure to bulk oil and lingering residues.
On many shores the process of wildlife recovery began soon after the bulk oil dispersed naturally or was removed. Surviving wildlife was supplemented by plant and animal recolonizers. Recovery is likely to be protracted in the case of sheltered shores that continue to harbour deep-seated lingering residues of oil (e.g., some muddy shores in Milford Haven).
As a result of the incident, fishing activity was banned. However, following intensive Government testing of shellfish and finfish, the ban was lifted in stages.
The visual aesthetic appeal of most shores used for recreation was largely restored by the summer of 1996, by which time bathers, surfers and SCUBA divers returned to many localities along the coast of South-West Wales.
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