The scientists were flying over the Belgian sector of the North Sea as part of a survey of sea mammals and research into pollution. To the northwest of the Westhinder sand bank, around 37 kilometres from the coast at Nieuwpoort they noticed a group of around 25 common bottlenose dolphins. They were swimming in a northerly direction.
RBIS says that solitary common bottlenose dolphins are sometimes spotted. However, the presence of such a large group in Belgian waters is exceptional.
A possible explanation the large number of pelagic fish such as herring and mackerel in the area. Pelagic’ comes from the Greek word for sea, ‘Pelagos’. These fish species travel in schools, throughout the entire water column from just above the seabed to the surface.