Passive acoustic monitoring of cetacean at Josephine Seamount, Portugal.

In the past years, the development of a variety of passive acoustics recorders has provided a unique way of acquiring information about marine mammal species in remote regions of the ocean. During the NATO Undersea Research Centre Sirena 10 cruise an ecological acoustic recorder (EAR) was deployed to monitor the presence of marine mammal. The EAR was deployed on May 13, 2010 at a depth of 944 m in the vicinity of Josephine seamount (37 deg; 02.087’N, 013¢ª 51.733W, south west Portugal) and programed for a recording time of 40 s every 2 min. For the detection and classification of echolocation clicks we integrated the visual analysis of spectrograms with the analysis performed by an automatic detector/classification system called M3R, developed by the Naval Undersea Warfare Center Division. M3R has been successfully operated for the analysis of recording from different US Navy ranges. Cetaceans detected include beaked whales, sperm whales, pilot whales, risso’s dolphins, and dolphins. Hourly and daily distributions of signals were calculated. Beaked whales have been regularly detected everyday and the echolocation activity has been found to be higher at night. This suggests that Josephine seamount represents a good habitat for these deep diving cetaceans. [NATO Undersea Res. Ctr. funded and operated the sea trial Sirena 10.]