2004 Strategic Environmental Assessment SEA5 Distribution and movements of harbour seals around Orkney, Shetland and the Wash

This report is a contribution to the Strategic Environmental Assessment (SEA5) conducted by the Department of Trade and Industry (now Department of Energy and Climate Change). 30 harbour seals in Orkney and Shetland and 10 in the Wash were captured and satellite tagged between October 2003 and March 2004. Each seal was tracked for an average of 150 days. As anticipated from initial satellite tagging in St Andrews Bay animals were found to travel much further to forage than previously anticipated. A high degree of individual variation in foraging behaviour of animals was found in Orkney and Shetland. The distance travelled to forage ranged between 5 and 150 km. In the Wash foraging behaviour was more consistent, the majority of foraging occurring between 75 and 120 km from haul-outs. The movement data received from the tags, combined with information on the number of animals counted during aerial surveys at haul-outs have been used to predict at-sea usage of the populations in question.