The status of breeding grey seals (Halichoerus grypus) on the east and south-east coasts of Ireland

A two year survey was conducted to estimate the population status of grey seals on the east and south-east coasts of Ireland and to document the types of habitat used. Surveys were concentrated around the known breeding sites of Lambay Island on the east coast and the Great Saltee on the south-east coast, during the breeding seasons of 1997 and 1998. The standard technique of through-counting was used to estimate pup production and mortality. Population estimates were calculated from the total pup production using the multipliers given in the grey seal life-history table. The total grey seal pup production was estimated at 41 and 49 for the east coast group, and 100 and 128 for the south-east group in 1997 and 1998, respectively. The population estimate for the east coast group was between 172 and 221 and between 448 and 576 for the south-east group. Estimated pup mortality for the east coast group was 7.3% and 2.0% and 3.0% and 8.6% for the south-east group in 1997 and 1998, respectively. Most pups were found on beaches, however data from the Great Saltee suggests that beach-cave sites were the preferred habitat early in the breeding season. This study has provided up-to-date information on an otherwise little studied marginal colony.