Foto 1: (IMAGE) Aarhus University Caption The study site with the oil and gas platform Dan-F in the Danish sector of the central North Sea. To the right a small service vessel and a yellow buoy with autonomous acoustic recorders placed at the seabed, listening for harbour porpoises for two years. Credit Photo: Jeppe Balle Dalgaard. Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.