More dolphins off the Belgium coast
It is thought that dolphins are swimming in more southerly waters in search of more food.
Two types of dolphin live in the North Sea: porpoises and white-beaked dolphins.
Porpoises are the more prevalent of the two off the Belgian Coast. There are some 2,000 in local waters.
White-beaked dolphins are rarer. Jan Haelters of the Institute for Natural Sciences says that their number has increased over the past thirty years.
They are swimming in more southerly waters because food is present in greater amounts than in northern seas.
White-beaked dolphins can grow to three metres in length. They seek out human company and enjoy following ships.
Porpoises are far more shy and shun contact with humans.