Cuvier’s beaked whale diving behavior as obtained by visual observation methods and consequences in terms of visual detection during surveys

We studied Cuvier's beaked whale (Ziphius cavirostris) behavior in the northern Mediterranean Sea, using conventional boat-based survey methods, including a towed hydrophone array. Between 2007 and 2012, 18 ziphius groups were sighted with suitable weather and sea conditions and data were collected during 80 minutes in average for each group. The observed surface/dive sequences followed the beaked whales specific diving pattern, with feeding dives (61 minutes long in average) separated by series of breathing phases (178 secondes long in average) and non-feeding dives (12.2 minutes long average). Our results are consistent with those obtained worldwide with tagging techniques.