Antarctic blue whales in the southern Indian Ocean: a multi-year and multi-site database of Z-call detections

Date 2016-09
Author(s) Leroy Emmanuelle C.1, Royer Jean-YvesORCID1, Bonnel Julien2, Samaran Flore2
Affiliation(s) 1 : CNRS & Université de Brest, Laboratoire Géosciences Océan, IUEM rue Dumont d’Urville, 29280 Plouzané
2 : ENSTA-Bretagne, Lab-STICC, 2 rue François Verny, 29806 Brest Cedex 9
DOI 10.17882/46124
Publisher SEANOE
Abstract

As part of the OHASISBIO project, since January 2010, a network of 6 to 8 autonomous hydrophones is deployed in the southern Indian Ocean (Fig. 1) to monitor the low-frequency sounds (0-120 Hz) carried by the ocean. These acoustic data provide unique information on the seasonal presence of several species and sub-species of large baleen whales. Among them, the Antarctic blue whale (Balaenoptera musculus intermedia) has a distinct call between 18 and 26 Hz, easily recognizable by its Z-shape in a time-frequency diagram. We designed an automatic Z-detector (Socheleau et al., 2015) to cense the Z-calls in our multi-year, multi-site acoustic dataset.  The resulting database consists of several metrics: time of detection of each individual call, the ambient noise level between 40 and 60 Hz, and the ratio between the whale chorus between 25 and 27 Hz over the noise level between 30 and 33 Hz.

The rationale for these metrics and the interpretation of the results can be found in the paper by Leroy et al. (2016; see reference below).

Layout of the OHASISBIO hydroacoustic stations (stars) in the Southern Indian Ocean

Figure 1: Acoustic records available for Antarctic blue whale Z-call detections.

© E Leroy / CNRS-U.Brest LGO

https://www.seanoe.org/data/00350/46124/illustrations/illustration-11.gif

Figure 2: Acoustic records available for Antarctic blue whale Z-call detections.

© E Leroy / CNRS-U.Brest LGO

Licence CC-BY-NC
Utilisation Data are published without any warranty, express or implied. The user assumes all risk arising from his/her use of data. Data are intended to be research-quality and include estimates of data quality and accuracy, but it is possible that these estimates or the data themselves contain errors. It is the sole responsibility of the user to assess if the data are appropriate for his/her use, and to interpret the data, data quality, and data accuracy accordingly. Authors welcome users to ask questions and report problems.
Acknowledgments The authors wish to thank the Captains and crews of RV Marion Dufresne for the successful deployments and recoveries of the hydrophones of the OHASISBIO experiment and of ORV Sagar Kanya for the recovery of the RAMA hydrophone. French cruises were funded by the French Polar Institute (IPEV; cruises VT109/112-MD174/175, VT115-MD185, VT119-MD189, VT128-MD193, VT135-MD197, VT141-MD200 and VT146-MD201), with additional support from INSU-CNRS. We thank NOAA/PMEL and INCOIS for the opportunity to recover the RAMA hydrophone. The hydroacoustic stations were funded by INSU-CNRS and by Région Bretagne (CPER ODO 2007-2015).
Data
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How to cite 

Leroy Emmanuelle C., Royer Jean-Yves, Bonnel Julien, Samaran Flore (2016). Antarctic blue whales in the southern Indian Ocean: a multi-year and multi-site database of Z-call detections. SEANOE. https://doi.org/10.17882/46124