Patterns of sound production in diving sperm whales in the northwestern Mediterranean

摘要

Passive acoustic tracking of sperm whales was conducted during three cruises (2001, 2002, and 2003) in the northwestern part of the Mediterranean Sea using a 128-element towed linear array with real-time beamforming capabilities. This allowed angular separation of sperm whales clicking from different horizontal directions, as well as an enhanced signal-to-noise ratio. Thus, when several diving animals were present, the description of individual click series was possible. Over a total of 279 complete dives, sperm whales were recorded clicking an average of 35 min per dive. The acoustic repertoire heard from diving sperm whales consisted of usual clicks, creaks, codas, and trumpets. Trumpets occurred at the beginning of 45 dives. One hundred and thirty-one codas, 98% belonging to the Mediterranean pattern 3+1, were recorded, usually at the end of the dive.