Grey Seal Numbers in the Wadden Sea and on Helgoland in 2022-2023

Expert Group Marine Mammals

Since 2008, coordinated annual surveys are carried out to count grey seals in the Wadden Sea, covering sandbanks in the Netherlands, Germany and Denmark. To assess development of the Wadden Sea breeding population, grey seal pups are counted during the pupping season between November and January. Trends in numbers of grey seals using the Wadden Sea and Helgoland are assessed by counting the seals in March and April when they are going through their moult.As grey seals move between haulout sites, we use the largest numbers of grey seals obtained within the shortest feasible timeframe for our trend analysis, thereby restricting the possibility of counting the same individuals more than once. All surveys areas were covered using aerial surveys except on Helgoland where land-based counts are carried out during moult and, starting this season, a drone was used during the pupping season.

This report was published 03.07.2023.

This report should be cites as: Schop J., Brasseur S., Galatius A., Hamm T., Jeß A., Meise K., Meyer J., Stejskal O., Siebert U., Teilmann J., Thøstesen C. B. (2023) Grey Seal Numbers in the Wadden Sea and on Helgoland in 2022-2023. Common Wadden Sea Secretariat, Wilhelmshaven, Germany.

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