SC/65b/Forinfo18
OVERVIEW OF THE IWC IDCR/SOWER CRUISE ACOUSTIC SURVEY DATA Fannie W. Shabangu1,2 and Ken Findlay2 1. Fisheries Branch, Department of Agriculture, Forestry and Fisheries, Private Bag X2, Roggebaai, Cape Town, 8012, South Africa 2. Mammal Research Institute Whale Unit, University of Pretoria, South Africa Contact e-mail:
[email protected] Abstract The South African Blue Whale Project is aimed at estimating the relative abundance, distribution and seasonal movements of Antarctic blue whales (Balaenoptera musculus intermedia) within the South Eastern Atlantic Ocean. As part of the project, we applied for, and received, the International Whaling Commission’s International Decade of Cetacean Research/Southern Ocean Whale and Ecosystem Research (IWC IDCR/SOWER) Antarctic and low latitude acoustic recordings from sonobuoy deployments on these cruises. The examination and collation of the data resulted in the compilation of a dataset which included the sourcing and reviewing of acoustic files and the development of a database comprising both acoustic recording files and associated station data, while also removing duplicate files. Cataloguing, file reviewing and naming of the acoustic data resulted in some 7500 acoustic recording files from over 700 stations across both the IWC SOWER Antarctic cruises from 1996/1997 through to 2008/2009 in Areas I-VI, and the three blue whale cruises off Australia, Madagascar and Chile. A total of 1547.76 hours of recordings have been initially reviewed and blue whale vocalizations (either Z or D calls) have been detected on 4100 of the 7246 recorded files from the Antarctic. The incidence of call rates (of both call types) from these acoustic files is currently being investigated. INTRODUCTION The South African Blue Whale Project of the Mammal Research Institute Whale Unit, University of Pretoria, applied for and received the IWC IDCR/SOWER Antarctic and low latitude blue whale cruise acoustic data from 1996/1997 through to 2008/2009 in 2013. These data have been collated and catalogued into a single dataset and initial reviews of blue whale calls within the individual acoustic recording files have been carried out. This paper summarises this compilation of this complete circumpolar Antarctic acoustic dataset of the IWC IDCR/SOWER cruises. ACOUSTIC RECORDINGS AND COMPILATION OF THE DATASETS The IWC IDCR/SOWER acoustic data were collected from the two Japanese research vessels the Shonan Maru, (SM1) and the Shonan Maru No. 2, (SM2) (both vessels - LOA: 64.8 m, Beam: 10.2 m) during the austral summers, i.e. December to February between 1996 and 2009 (Table 1). The majority of the surveys covered the region between the ice edge and 60° S (Ensor et al., 1996-2009). Acoustic stations were generally carried out using 53D DiFAR sonobuoys deployed by hand from the decks of the vessels. The majority of these sonobuoys were programmed for 30 m depth (with some set to 120m) and all were set for 8 hours. Acoustic monitoring times at stations ranged between 5 minutes and 17 hours, although recordings were often a fraction of this. Acoustic recording files were sourced from archives held by the Cornell Lab of Ornithology and from individual cruise participants (Kate Stafford and Paul Ensor). Summaries of the observed stations were extracted from the cruise reports (Ensor et al., 1996-2009), while acoustic data forms and the associated sightings forms were supplied by the IWC Secretariat. Acoustic data files from the 1997/1998 Antarctic cruise are still to be sourced. Acoustic data were scrutinized and characterized using Raven Pro (Bioacoustics Research Program, 2011). Antarctic blue whale’s call detection templates were created and applied in eXtensible BioAcoustic Tool (XBAT) software.
RESULTS AND DISCUSSION After database compilation, some 7246 recorded acoustic files were available from the 743 stations from the Antarctic cruises. A total of 1547.76 hours of recordings have been initially reviewed and blue whale vocalizations (either Z or D calls) have been detected on over 4100 of the 7246 recorded files. Despite fairly uniform longitudinal coverage of the IWC Antarctica areas I-VI being surveyed in the series of three circumpolar surveys during the IWC’s IDCR and SOWER programmes, the acoustic survey effort in terms of acoustic stations and sonobuoy deployment times varied significantly between the years (and therefore regions) of the cruises (Table 2). A total of 743 stations were monitored, the distribution of which are shown in Figure 1. Acoustic data files from the 1997/1998 Antarctic cruise have not yet been sourced, although the data files from the preceding Chile blue whale cruise (the cruises ran back to back) have been reviewed, including the identification of some files dated within the Antarctic cruise time period. Reconciliations of these data are pending the sourcing of the 1997/1998 Antarctic cruise data. Acoustic files were logged at hourly intervals prior to and including 2003. From 2004, acoustic recording files were logged in 5 minutes intervals (at a sample rate of 1000 Hz) and although animal calls were monitored for a longer time period, acoustic recordings were made over short intervals. In some cases, marine mammal vocalizations may have been recorded but not recorded in the acoustic monitoring record. The acoustic recording files were saved in an Audio Interchange File Format (AIFF) at a 16-bit encoding and the majority of the sound files had 2 channels. From 2005 and onwards, the sample rate was increased to 48kHz; the sampling interval also decreased to 10 minutes and sound file type was changed from AIFF to Waveform Audio File format (WAVE) at a 16-bit signed encoding.
Figure 1. Distribution of acoustic stations carried out on IWC SOWER Antarctic cruises, 1996 to 2009. It should be noted that the 1997/1998 Antarctic data are still to be sourced. Although the reconciliation of a full circumpolar dataset has still be completed (the 1997/1998 Antarctic acoustic data are still to be sourced) the compilation of this dataset has allowed for the merging of both acoustic data from the recordings and associated metadata (including both spatial and temporal data) from the station and acoustic record forms. Further analyses of these data (and particularly call rates) by locations (position, depth and distance from the ice edge), and timing (both across the summer season and by time of day) and in association with both observed groups of blue whales and broader blue whale densities obtained from line-transect visual observations could provide important information on Antarctic blue whale calling behaviour. Such behaviour is of importance in the analyses of autonomous acoustic recordings from the region.
Table 1. Summary of available acoustic data with Antarctic blue whale vocalization from the IWC IDCR/SOWER cruises. It should be noted that the complete 1997/1998 Antarctic data series is still to be sourced. Cruise Year
Vessel
Recording dates
Total hours monitored
Number of sonobuoys
1994/1995 1995/1996 1996/1997
SM2 SM1 SM1
13.35 39.85 42.67
10 12 13
Australia Mauritius Antarctic
¤ ¤ II
¤ ¤ 00°-30°W
1997/1998
SM2 SM1
07-26 Dec 1995 10-24 Dec 1996 15 Jan- 04 Feb 1997 08-12 Feb 1997 09 Dec 199702 Jan 1998 17 Dec 1997-02 Jan 1998 29 Jan 1998 08 Jan-23 Feb 1999 13 Jan-21 Feb 1999 14 Jan 2000-12 Feb 2000 14 Jan 2000-13 Feb 2000 12 January 2001
12.42 25.28
4 16
Antarctic Chile
II ¤
00°-30°W 70°-77°W
100.97
23
Chile
¤
70°-77°W
5.00 190.22
2 97
Antarctic Antarctic
60°-25°W 35°-130°E
34.02
12
Antarctic
25.97
7
Antarctic
II III and IV III and IV I and II
162.86
47
Antarctic
I and II
80°-55°W
2.38
1?
Antarctic
V, VI and I
175°-110°W
31 Dec 2001-23 Jan 2002 23 Dec 2002-24 Feb 2003 22 Dec 2002-24 Feb 2003 26 Dec 2003-26 Feb 2004 26 Dec 2003-28 Feb 2004
63.30
20
Antarctic
V
114.22
31
Antarctic
V
44.93
23
Antarctic
V
71.01
24
Antarctic
V
142.89
48
Antarctic
V
Antarctic
III
130°W150°E 150°E170°W 150°E170°W 170°E170°W 170°E170°W 00°-70°E
SM2 1997/1998 1998/1999
SM2 SM1 SM2
1999/2000
SM1 SM2
2000/2001
2001/2002
SM1 & SM2 SM1
2002/2003
SM1 SM2
2003/2004
SM1 SM2
2004/2005
2005/2006
SM1 & SM2 SM2
2006/2007
SM2
2007/2008
SM2
2008/2009
SM2
no acoustic data collected *
18 Jan-10 Feb 2006 29 Dec 2006-08 Feb 2007 26 Dec 2007-13 Feb 2008 21 Jan-09 Feb 2009
Survey Area
IWC Area
Positions (longitude range)
35°-130°E 80°-55°W
91.09
33
Antarctic
III
00°-20°E
76.32
51
Antarctic
III
00°-20°E
251.37
59
Antarctic
IV
105°-120°E
40.02
24
Antarctic
IV
82°-95°E
Table 2. The number of acoustic stations monitored on IWC IDCR / SOWER cruises by IWC Management Area.
Area Area I Area II Area III Area IV Area V Area VI Total
Number of Stations 68 43 199 171 190 72 743
ACKNOWLEDGEMENTS We are extremely grateful to the International Whaling Commission for granting permission to use the IWC IDCR/SOWER acoustic data together with the cruise reports, acoustic data records and visual survey data. Drs Chris W. Clark, Kate Stafford and Paul Ensor are thanked for providing the acoustic data files from different cruises. This overview would not have been possible without the guidance and introduction to passive acoustic monitoring software by Drs Kate Stafford and Flore Samaran. We thank the South African National Antarctic Programme and National Research Foundation for funding the South African Blue Whale Project. KF was funded by the Island Foundation. REFERENCES Bioacoustics Research Program. 2011. Raven Pro: Interactive Sound Analysis Software (Version 1.4) [Computer Software]. Ithaca, NY: The Cornell Lab of Ornithology. Available from http://www.birds.cornell.edu/raven. Ensor, P., Findlay, K., Hara, T., Hedley, S., Pitman, R., Sekiguchi, K., Tsurui, T. And Yamagiwa, D. 1997. 1996-97 IWC-Southern Ocean Whale and Ecosystem Research (IWC-SOWER) Antarctic Cruise, Area II. Paper SC/49/SH7 presented to the IWC Scientific Committee, September 1997. 47pp. Ensor, P., Sekiguchi, K., Doherty, J., Kleivane, L., Ljungblad, D., Marques, F., Matsuoka, K., Narita, H., Pitman, R. and Sakai, K. 1999. 1998-99 IWC-Southern Ocean Whale and Ecosystem Research (IWC-SOWER) Antarctic cruise, Areas III and IV. Paper SC/51/Caws6 presented to the IWC Scientific Committee, May 1999, Grenada, WI. 61 pp. Ensor, P., Findlay, K.P., Hucke-Gaete, R., Kleivane, L., Komiya, H., Ljungblad, D., Marques, F., Muira, T., Sekiguchi, K. and Shimade, H. 2000. 1999-2000 IWC-Southern Ocean Whale and Ecosystem research (IWC-SOWER) Antarctic Cruise, Areas I and II. Paper SC/52/IA1 presented to the IWC Scientific Committee, June 2000, in Adelaide, Australia. 51 pp. Ensor, P., Matsuoka, K., Marques, F., Miura, T., Murase, H., Pitman, R., Sakai, K. and Van Waerebeek, K. 2001. 2000-2001 International Whaling Commission - Southern Ocean Whale and Ecosystem Research (IWC-SOWER) Circumpolar Cruise, Area V, VI and I. Paper SC/53/IA5 presented to the IWC Scientific Committee, July 2001, London. 56 pp. Ensor, P., Sekiguchi, K., Cotton, J., Hucke-Gaete, R., Kariya, T., Komiya, H., Ljungblad, D., Narita, H., Olson, P. and Rankin, S. 2002. 2001-2002 International Whaling Commission-Southern Ocean Whale and Ecosystem Research (IWC-SOWER) circumpolar cruise, Area V. Paper SC/54/IA2 presented to the IWC Scientific Committee, April 2002, Shimonoseki, Japan. 51 pp. Ensor, P., Matsuoka, K., Hirose, K., Ljungblad, D., Minami, K., Olson, P., Rankin, S., Stevick, P., Tsunekawa, M. and Ugarte, F. 2003. 2002-2003 International Whaling Commission-Southern Ocean Whale and Ecosystem Research (IWC-SOWER) Circumpolar Cruise, Area V. Paper SC/55/IA1 presented to the IWC Scientific Committee, May 2003, Berlin. 65 pp. Ensor, P., Matsuoka, K., Komiya, H., Ljungblad, D., Miura, T., Morse, L., Olson, P., Olavarria, C., Mori, M. and Sekiguchi, K. 2004. 2003- 2004 International Whaling Commission-Southern Ocean
Whale and Ecosystem Research (IWC-SOWER) Circumpolar Cruise, Area V. Paper SC/56/IA13 presented to the IWC Scientific Committee, Sorrento, Italy, July 2004. 68 pp. Ensor, P., Findlay, K., Friedrichsen, G., Hirose, K., Komiya, H., Morse, L., Olson, P., Sekiguchi, K., Van Waerebeek, K., and Yoshimura, I. 2005. 2004-2005 International Whaling CommissionSouthern Ocean Whale and Ecosystem Research (IWC-SOWER) Cruise, Area III. Paper SC/57/IA1 presented to the IWC Scientific Committee, June 2005, Ulsan, Korea. 90 pp. Ensor, P., Komiya, H., Olson, P., Sekiguchi, K. and Stafford, K. 2006. 2005-2006 International Whaling Commission- Southern Ocean Whale and Ecosystem Research (IWC-SOWER) cruise. Paper SC/58/IA1 presented to the IWC Scientific Committee, June 2006, St Kitts and Nevis, WI. 58 pp. Ensor, P., Komiya, H., Beasley, I., Fukutome, K., Olson, P. and Tsuda, Y. 2007. 2006-2007 International Whaling Commission—Southern Ocean Whale and Ecosystem Research (IWCSOWER) Cruise. Paper SC/59/IA1 presented to the IWC Scientific Committee, June 2007, Anchorage, Alaska, USA. 58 pp. Ensor, P., Minami, K., Morse, L., Olson, P. and Sekiguchi K. 2008. 2007–2008 International Whaling Commission-Southern Ocean Whale and Ecosystem Research (IWC-SOWER) cruise. Paper SC/60/IA1 presented to the IWC Scientific Committee, June 2008, Santiago, Chile. 51 pp. Ensor, P., Komiya, H., Kumagai, S., Kuningas, S., Olson, P. and Tsuda, Y. 2009. 2008-2009 International Whaling Commission-Southern Ocean Whale and Ecosystem Research (IWCSOWER) Cruise. Paper SC/61/IA19 presented to the IWC Scientific Committee, June 2009, Madeira, Portugal. 54 pp.
