Measurements by drifting surface buoys. This system is a drifting mooring consisting of a surface buoy fastened to a floating anchor by a cable (trip line, buoy rope). It has to monitor as precisely as possible the water volume in which the floating anchor is immersed. The surface buoys are traced by Argos satellites.

Monitoring the specific composition and spatial and temporal distribution of beachings over the long term in order to identify tendencies and events affecting populations of marine mammals in French waters. This is the longest series of data in France concerning these species.