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  • Article
    Echolocation clicks of free-ranging Cuvier's beaked whales (Ziphius cavirostris)
    (Acoustical Society of America, 2005-06) Zimmer, Walter M. X. ; Johnson, Mark P. ; Madsen, Peter T. ; Tyack, Peter L.
    Strandings of beaked whales of the genera Ziphius and Mesoplodon have been reported to occur in conjunction with naval sonar use. Detection of the sounds from these elusive whales could reduce the risk of exposure, but descriptions of their vocalizations are at best incomplete. This paper reports quantitative characteristics of clicks from deep-diving Cuvier's beaked whales (Ziphius cavirostris) using a unique data set. Two whales in the Ligurian Sea were simultaneously tagged with sound and orientation recording tags, and the dive tracks were reconstructed allowing for derivation of the range and relative aspect between the clicking whales. At depth, the whales produced trains of regular echolocation clicks with mean interclick intervals of 0.43 s (±0.09) and 0.40 s (±0.07). The clicks are frequency modulated pulses with durations of ~200 µs and center frequencies around 42 kHz, –10 dB bandwidths of 22 kHz, and Q3 dB of 4. The sound beam is narrow with an estimated directionality index of more than 25 dB, source levels up to 214 dBpp re: 1 µPa at 1 m, and energy flux density of 164 dB re: 1 µPa2 s. As the spectral and temporal properties are different from those of nonziphiid odontocetes the potential for passive detection is enhanced.
  • Working Paper
    Photoidentification catalog of Cuvier's beaked whale (Ziphius cavirostris) in the Ligurian Sea
    (Woods Hole Oceanographic Institution. Contact: Alessandro Bocconcelli,, 2008-04-08T19:56:48Z) Revelli, Eletta ; Pusser, Todd ; Bocconcelli, Alessandro ; Ballardini, Marco ; Sturlese, Albert ; Johnson, Mark P.
    A photo-ID catalog of Cuvier's beaked whales was compiled by analyzing data collected in the Ligurian Sea from 1998 to 2007. Data were collected during dedicated surveys for beaked whales, opportunistic whale watching cruises, and during several tagging efforts. A total of 2,300 photographs was collected and referenced to time and GPS position. Of these photographs, 650 were of sufficient quality to use for photo-identification. Photographs were divided into four categories, based on scarring and pigmentation patterns: very distinctive (heavily scarred and/or bold pigmentation), distinctive (many distinct scars and/or bold pigmentation), slightly distinctive (few scars and lack of bold pigmentation), and not distinctive (no scars and solid brown animal). 127 individual whales were identified, of which 10 were classified as adult males, 3 as adult females, 3 as calves, and 27 as immature whales, based on the above criteria. An additional 26 whales were classified as possible males, and 28 as possible females. During the 9 year study period, 34 whales were resighted, and the longest time between resights was 7 years.