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Experts observe a stable harbour seal population in the Wadden Sea

In August 2020, 28,352 harbour seals were counted in the Danish-Dutch-German Wadden Sea and Helgoland. This is the highest count yet recorded since 1975, although only with a slight increase of 2% compared to 2019.

Young harour seal. Photo: AB

The number of newborns also reached a record high with 9,954 observed pups. In their new report “Trilateral surveys of Harbour Seals in the Wadden Sea and Helgoland in 2020”, the Expert Group on Seals (EG-Seals) of the Trilateral Wadden Sea Cooperation estimates that the total population of harbour seals in the Wadden Sea is 41,700, based on the assumption that that about one third of the seals were in the water during the survey. The trilaterally coordinated aerial surveys are conducted twice a year – during the pupping season in June and during the moulting season in August, when harbour seals spend more time on land.

The EG-Seals state that since 2012, they have been observing a stabilizing trend in the population, with an average annual growth rate of 1.2%, which is much lower than in previous decades. “Looking at the regions, we detect large increases and decreases from year to year”, says Ursula Siebert, chair of the EG-Seals and professor at the Institute for Terrestrial and Aquatic Wildlife Research (ITAW). “There could be different reasons for this, such as a variation in the survey date, varying numbers of seals hauling out, weather or a migration between areas. This is why it is important to treat the Wadden Sea as an ecological entity and coordinate the trilateral counts to get an overview on the status of the entire harbour seal population.”

Complete article on te website Waddensea-worldheritage.

Download the complete report: Trilateral surveys of Harbour Seals in the Wadden Sea and Helgoland in 2020 via the website van de Waddensea-worldheritage.