More grey seals counted in the Wadden Sea

The number of adult grey seals counted during the 2026 moult increased by 3.6% compared with 2025, reaching a total of 12,497 animals. By far the highest number of grey seals during this period was recorded in the Dutch part of the Wadden Sea (8,981).

The number of pups increased by 10% compared with last year, reaching 3,385 recorded pups. This means that the upward trend is continuing. Over the past five years, pup numbers have increased by an average of 12% per year. As in previous years, most pups were found in the Dutch part of the Wadden Sea (1,731), followed by Helgoland (1,077) and Lower Saxony (575). With an increase of 22.3% compared with 2024–2025, the strongest relative growth was observed in Lower Saxony. Only a few pups were observed in the eastern Wadden Sea: one in Schleswig-Holstein and one in Denmark. However, later observations of several pups indicate that births do occur in this area.

The trilateral Expert Group on Marine Mammals, consisting of researchers and managers from Denmark, Germany and the Netherlands, expects the growth of the grey seal population to expand further eastwards. In the eastern Wadden Sea, the few pups that are born arrive later in the season, which may indicate younger mothers. As has previously been observed in, among other places, the Netherlands, the peak of the pupping season is expected to shift earlier as the colony becomes larger.

In addition, many grey seals appear to moult in different locations from those where they breed. “Grey seals travel large distances across the North Sea, meaning that these surveys include both local animals and animals from other regions,” says seal researcher Jessica Schop of Wageningen Marine Research. “This highlights the importance of studying population dynamics on a broader, international scale. For this reason, it is important to include colonies outside the Wadden Sea — such as those in the Dutch Delta area — in the annual assessment of population development. This is already being done for the colony on Helgoland.”

In the Wadden Sea, grey seals live alongside harbour seals. The populations of both species are counted annually across the international Wadden Sea and reported separately. Grey seals are the largest predators along the Wadden coast and are among the area's most iconic species. The grey seal population in the Wadden Sea is counted annually as part of the international cooperation between Denmark, Germany and the Netherlands.