Harbour porpoises (Phocoena phocoena) are the smallest cetaceans in the North Sea. They have recovered from being rare to nowadays being present throughout the year in numbers reaching to 80 000 in the Dutch sector or the North Sea. The only area where studies were conducted prior to the disappearance …

In Pembrokeshire/Wales harbor porpoise (Phocena phocena) make daily use of Ramsey sound, a narrow ocean channel characterized by strong tidal currents. The sound is an important socializing and feeding area for porpoise and was designated marine special area of conservation (MSAC) in 2004. The region …

For the Dutch economy the ports of Amsterdam and Rotterdam are crucial. To continue the competitive positions of both ports versus foreign ports, the entrance channels to both ports have to be optimal. That said, it is however a problem. The largest ships calling at these ports have a very deep draught, …