Results of harbour seal monitoring in the Dutch Wadden Sea
Last summer, 7,661 harbour seals were counted in the Dutch Wadden Sea; an increase of 4% compared to last year. In the international Wadden Sea, the growth is 2% compared to the same period a year ago. During the birthing season, 2,542 newborns were registered in the Dutch Wadden Sea as well as a total of 9,954 pups in the international Wadden Sea. This amounts to an increase of 9% in the Netherlands and an increase of 3% in the international Wadden Sea.
After years of growth - at 8.9% per year until 2012 - the population of harbour seals in the international Wadden Sea appears to have stabilised over the past eight years, with an average growth of 1.2% per year (current population is estimated at 41,700 animals). The trilateral seal specialists group (EG-Seals) concluded that this trend in the Wadden Sea is remarkable, as reproduction has increased at about 10,000 pups per year for eight years, but seemingly does not contribute to the growth of the total number of harbour seals. Further studies are needed to understand the underlying mechanisms.