85,000+ porpoises off Netherlands
WAGENINGEN _ You can hear and see them as they follow your boat. But how many porpoises are there in the Dutch part of the North Sea? Marine researchers at IMARES Wageningen UR have provided the first complete estimate: 85,572. They said they have spotted that many of the small toothed whales off the Netherlands during aerial surveys in recent years.
The number represents nearly half of all porpoises across the southern North Sea, the marine research institute reported. The finding makes the harbor porpoise (Phocoena phocoena) the most abundant marine mammal species in Dutch waters. The institute carried out aerial surveys in July, October and November of 2010 and in March, 2011. The researchers found different distribution patterns of porpoises between seasons. Calves were mainly seen in July, indicating that porpoises also reproduce in Dutch waters.
The highest estimate (85,572) dates from March, 2011. It shows that after a sharp decline in the first half of the 20th century, the number of harbor porpoises in Dutch waters has increased significantly in recent decades. The harbor porpoise is widespread in cooler coastal waters of the North Atlantic, North Pacific and the Black Sea. They inhabit fjords, bays, estuaries and harbors, hence their name.