SMRU Grey Seal Tracking in the North Sea, 1991-1993

The movements of 14 grey seals Halichoerus grypus Fab. caught at the Farnes in north-east England (12) and Abertay in eastern Scotland (2) between August 1991 and July 1993 were investigated using Argos Satellite Relay Data Loggers (SRDL). The data are a spreadsheet of points representing seal locations. The low and irregular uplink rate from an SRDL on a seal to the Argos satellites can result in potentially significant errors in some location fixes. Therefore, locations were filtered using an algorithm based on a ?maximum speed parameter? of 2 m s-1. This filter rejected 17% of the primary locations that would have required an unrealistic rate of travel to achieve. However, this does not remove all invalid locations hence there are still some datapoints occurring inland. There are 9454 locations in the spreadsheet covering all months of the year except February and March.