The largest mammals in this area are the seals and harbor porpoises. The latter is the most common cetacean along the Dutch coast.
In the first half of the 20th century, an abundance of seals lived in the Delta. Pollution and the upheaval of the Delta Works drove most of them away. Now that the work (making of the sturm surge Barrier) has been completed in the Delta, and care for the environment is steadily gaining in importance, their numbers are slowly increasing again. At the beginning of the 21st century, over a 150 seals could be seen swimming in the Delta.
In late June and early July, the seal pups are born. During this time, the mothers seek out the quieter spots. Once the pups have been born, they all return to their familiar haunts.
Before World War II Harbour Porpoises were abundant in the Eastern Sheldt. Researchers do know that after 1958 Harbour Porpoises were very rare across the Dutch and Belgian coasts. But nowadays Harbour Porpoises are making a comeback and common in the National Park of the Oosterschelde in the South of the Netherlands. Only recently, since 2001, researchers dare to speak of a residency. The Oosterschelde really is an important nursery ground for porpoises: calves are born every year in the Park and spotted regularly along the coastline together with their mother. But although the birth rate seems to have increased, it’s still not clear if the food availability in the South is enough to sustain a growing population of cetaceans, and sadly enough, strandings of porpoises are not unusual and even increasing. So are they really making a comeback or is it just keeping up appearances?
Were can you find these animals? Look below for a map .
-Seals are often be seen lying on the sandbars near Neeltje Jans and on the sandbar of Roggeplaat in the Eastern Sheldt. You can also see them at close range in the seal pool.
-The Harbour Porpoises can be seen year round in the Oosterschelde, even from land observation points at certain ‘hotspots’, like Zierikzee.
-you can make a boat trip along several sandbanks in the Western of Eastern Scheldt. These are the ideal resting place for seals and sea birds, which are abundant in the waters around Zeeland. Boot trips can be made at low tide.
-"a Seal", the sea animal hospital of Stellendam receives many sick seals. They can recover there and afterwards they will put into the sea again. You can take a guide-tour overthere and see the seals at short distance.