According to experts, the population of seals in the Wadden Sea has decreased for the third year in a row. A total of 22,621 seals were counted in the Wadden Sea of Denmark, Germany and the Netherlands as well as the island of Heligoland in August – 4 percent fewer than a year earlier, as the Wadden Sea Secretariat announced on Wednesday.
This is the lowest number since 2010 and the causes of the negative trend have not yet been clearly clarified. The numbers are collected in June and at the time of shedding in August. Seals are among the largest marine predators in the Wadden Sea.
“Given this continued decline in numbers, we can almost certainly assume that the population is declining,” said Anders Galatius of Aarhus University, lead author of the report. “It would be important to investigate the possible causes, which could include habitat degradation, food availability and increasing numbers of gray seals in the area.”
Counting in June and August
The count of young animals in June showed an increase of 10 percent compared to the previous year. A total of 9,334 young animals were counted in the Wadden Sea – 820 more than the year before. Increasing numbers were observed in three parts of the Wadden Sea: in Denmark the number of young animals increased by 23 percent, in Schleswig-Holstein by 12 percent and in the Netherlands by 18 percent. In Lower Saxony and Hamburg, however, a decline of 5 percent was recorded. No young animal was spotted on Helgoland. According to the information, it will only become clear in the next few years whether the number of young animals will follow the trend of the overall numbers.
During the annual coat change in August, the number of seals counted fell in almost all areas. Exceptions were Lower Saxony and Hamburg, where the number rose by 17 percent compared to the previous year to 5,639 animals. In Denmark the number of seals fell by 19 percent to 2,268 animals, and in Schleswig-Holstein by 5 percent to 7,936 animals. In the Netherlands, 6,706 seals were counted, 11 percent fewer than in 2022. Finally, 72 animals were recorded on Helgoland – in 2022 there were still 98, which means a decrease of 27 percent.
According to the Wadden Sea Secretariat, the number of seals observed during shedding has stagnated since 2010 and has been declining for three years. The causes could therefore be a deterioration of the habitat and disturbances in the Wadden Sea or off the coast – for example from fishing, shipping or wind turbines – as well as competition for resources with fishing or other marine mammals. Mortality as bycatch or as prey for other animals could also play a role.
