Increasing numbers of harbour seals and grey seals in the Solent

Abstract

Harbour seals (Phoca vitulina) and grey seals (Halichoerus grypus) are widely distributed in the temperate North Atlantic and currently listed as species of "Least Concern" (Figure 1; IUCN, 2019).However, within the UK there are contrasting population trends for these species.Harbour seals were severely impacted by phocine distemper virus (PDV) in 1988 and 2002, which resulted in up to 50% reductions in some UK subpopulations (SCOS, 2020). Recent results indicate that the overall UK harbour seal population has now recovered to levels similar to those of the late 1990s (estimated 44,100 animals; 95% CI 36,100-58,800); however, there have been significant regional differences in trends, with various subpopulations decreasing, stable, or increasing (SCOS, 2020;Thompson et al., 2019).In comparison, the UK grey seal population size is estimated to be 150,000 animals, with regular surveys of grey seal pup production showing an increasing trend since surveys began in the 1960s