Heat killing off cockles in the Wadden Sea; Could damage bird population

Cockles are dying in large numbers in the Wadden Sea due to the heat, according to researcher Roeland Bom of the Royal Netherlands Institute for Sea Research (NIOZ). The cockles population is resilient enough to survive the high mortality. But the consequences will be more severe for the birds that eat cockles, Bom said to Omrop Fryslan.

NIOZ received reports of dead cockles from Griend, Ameland, and Scheirmonnikoog, among other places. The agency is investigating.

In 2018 and 2019, there were also massive cockle deaths due to the warm weather. “In 2018, we saw it immediately after the enormous heat. That seems to be the case again now,” Bom said. He suspects that low tide coming during the hottest part of the day is part of the problem. “We think it’s something we’re going to see more and more with the warmer summers.”

While the cockles population will probably survive this increased mortality, the birds that rely on cockles for food may not be so lucky, Bom said. “In principle, the oystercatcher, the eider, and the knot is not doing well. The idea is that this is due to a lack of food. It may be that this will have direct consequences for the population of these birds.”

NIOZ is currently investigating the food stocks for these birds. “At the same time, we are intensively looking at the birds. This way, we try to find out how they respond to the changing world.”