Widespread presence of sperm whales in the north-western Mediterranean Sea was confirmed. Sperm whale echolocation ‘usual click’ trains, characteristic of foraging activity, were detected and classified from the recordings, providing information about the presence of sperm whales along the glider tracks. Passive acoustic monitoring loggers were deployed on vertically profiling oceanographic gliders surveying the north-western Mediterranean Sea during winter 2012-2013 and June 2014. The sustained presence of oceanographic autonomous underwater vehicles in the area presents an opportunity to improve observation effort, enabling collection of valuable sperm whale distribution data, which may be crucial to their conservation. Habitat use by the endangered Mediterranean sperm whale subpopulation remains poorly understood, especially in winter. The integrated tag, to be called the Acousonde(trademark) 3B, is being revised for planned release in 2010. Tests of a mechanical sample of this integrated tag indicated the need to further reduce its size. Finally, a thorough redesign of the Bioacoustic Probe's shape prepared the way for a future cetacean tag that integrates attachment, flotation, and retrieval systems in a single hydrodynamic package. The new wideband recorder was announced for commercial sale in January 2009 as the Acousonde(trademark) 3A. Other improvements included 3D tilt and 3D compass to support more detailed study of kinematic behavior. USB flash-drive technology replaced infrared transfers for data offloading, speeding offload by a factor of 60 from 17 MB/hour to 1 GB/hour.
The resulting effort increased the design's maximum sampling rate from 20 kHz to 232 kHz and its maximum storage capacity from 1 GB to 8 GB (64 GB if battery limitations are neglected). In 2006, the Office of Naval Research (ONR) initiated support to Greeneridge Sciences to expand the capability of the first and only commercially-available broadband acoustic recording tag, the Bioacoustic Probe, to record high-frequency echolocation vocalizations of beaked whales and other odontocete species. Acoustic recording tags, in particular, offer the capability to record a subject's acoustic exposure as well as its vocalizations and kinematics, providing a complete picture of a wild animal's acoustically-related behavior. Instrumentation capable of monitoring free-ranging marine animals is an essential foundation for research on sound and marine wildlife.
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