Movements and foraging areas of grey seals in the North Sea

摘要: Summary 1. Grey seals Halichoerus grypus Fab. are large, numerous marine top predators. Fears concerning competition with fisheries have prompted calls for control measures. However, little is known about the areas where grey forage or distances they may travel. 2. The movements of 14 caught at Farnes in north-east England (12) and Abertay eastern Scotland (2) between August 1991 July 1993 were investigated using Argos Satellite Relay Data Loggers (SRDLs). A total 1461 seal days location behavioural data (mean 104·3 days per seal) covered all months year except February March. 3. on two geographical scales: long distant travel (up to 2100 km away); local, repeated trips from Farnes, other haul-out sites discrete offshore areas. 4. Long distance included visits Orkney, Shetland, Faroes, far into Eastern Atlantic North Sea. During moved speeds 75 100 km day–1 (0·87 1·16 m s–1). Most time, was directed sites. large travelled indicate that haul out not ecologically isolated those Shetland Faroes. 5. In 88% sea, individual returned same site which departed. durations these short 2·33 days) their destinations sea often localized characterized by a gravel/sand seabed sediment. This preferred burrowing habitat sandeels, an important part diet. This, fact dives primarily seabed, leads us conclude foraging areas. limited extents return-trips 39·8 km) suggest direct impact predation be greater within this coastal zone, especially near sites, rather than further offshore. 6. An average 43% seals’ time spent 10 km site, although identified considerably offshore. Proximity provide safety predation. Alternatively, periods used rest social interaction, we underestimating activity sites. 7. We movement patterns observed study persist through across Farnes. also such as could combined diet studies censuses map intensity. Such information essential component seal–fishery interaction models, upon management decisions should based.