Investigation launched into decline of seal population in Wadden Sea

A broad, two-year–long study into why the seal population in the Wadden Sea is declining starts this week. Despite relatively many seal pups being born, the common seal population in the Dutch part of the Wadden Sea dropped to 7,211 counted individuals in August 2023 - the lowest number since 2014. The researchers aim to find out why, RTV Noord reports.

David Goldsborough of the Van Hall Larenstein University of Applied Sciences in Leeuwarden is leading the study. National and international experts are also participating, including the seal sanctuaries in Pieterbieren, Stellendam, and on Texel.

“A relatively large number of pups are born, but it seems that not enough pups reach adulthood,” Goldsborough said. “About 15 percent of the pups disappear without a trace and we don’t know what happens to them. We don’t find any carcasses, we simply don’t know where they end up. It’s a mystery.”

This study will be as broad as the researchers can make it, Goldsborough said. “The common seals are counted, but there is no real monitoring, looking in the field to see what happens. We want to investigate how we can do that in the future. And we are going to look for missing data.”

According to Goldsborough, many factors can influence the population. “For example, fish can move to more northerly waters due to the warming of the water,” he said. Wind farms in the North Sea, where seals look for food, may also play a role. “Such shifts in the food web can have consequences,” the researcher told the broadcaster. “Whether we will succeed in finding answers within two years remains to be seen.”