Unusual mortality event of harbour porpoises in the Netherlands
Lonneke L. IJsseldijk and Anne-Marie Svoboda
In August 2021, nearly 200 dead harbour porpoises (Phocoena phocoena) washed ashore on the Dutch Wadden Sea Islands within just ten days. This is a remarkably high number, considering the annual average of about 600 stranded porpoises on the entire Dutch coastline. The stranded animals all appeared in a similar state of advanced decomposition. This indicated that they died some days to weeks before the stranding event, but likely all around the same time.