Published online by Cambridge University Press: 05 December 2011
Although common seals (Phoca vitulina L.) do occur in the Firth of Forth, the grey seal (Halichoerus grypus Fab.) is by far the most abundant species in the area. Some pups are born along the north shore of the outer firth but the vast majority are born on the Isle of May. This colony has increased in size from less than twenty-five pups in 1975 to more than 900 in 1986. Studies using conventional and radio tags indicate that many of the seals at the Isle of May originally came from the colony at the Farne Islands, off the Northumberland coast. Information from the Fame Islands population is used to predict future changes at the Isle of May. If current trends continue, more than 2000 pups could be born each year by the end of the century. However, it seems unlikely that this will occur. Management methods for controlling habitat damage are discussed.