Spatio-temporal patterns of Antarctic blue whale (Balaenoptera musculus intermedia) vocal behavior in the Weddell Sea


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Karolin.Thomisch [ at ] awi.de

Abstract

Although Antarctic blue whales (Balaenoptera musculus intermedia) are known to occur throughout the Southern Ocean, undertaking seasonal migrations between their breeding and feeding grounds, knowledge on spatio-temporal patterns in their distribution is limited. Here, passive acoustic recordings collected over three years from four locations at different latitudes along the Greenwich meridian south of 59°S, provided data on patterns in occurrence of stereotyped 3-unit vocalizations of Antarctic blue whales in the Weddell Sea. Highest vocalization rates occurred during austral summer at all recording locations, with calls detectable during 10 months in recordings from 59°S and 66°S, over 11 months in recordings from 69°S and year-round in recordings from coastal waters off the Antarctic continent at 70°S. Antarctic blue whale acoustic activity showed seasonal maxima that differed in timing between recorders, but were consistently present between years. Onset of increased acoustic presence occurred in November-December in the northernmost recorder at 59°S, in January in the recorders at 66°S and 69°S and in February in the southernmost recorder at 70°S. These results are consistent with a southbound migration of vocalizing Antarctic blue whales with at least some individuals migrating as far south as the Antarctic coastal waters during austral summer. A secondary increase in acoustic activity occurred during March and April in the recorders at 59°S and 66°S, respectively, supporting previous suggestions that migration of Antarctic blue whales is segregated in time. The absence of a corresponding secondary maximum at 69°S hints towards not all individuals migrating this far south, and that migratory destinations (or alternatively, vocal activity) may hence be spatially segregated. The year-round presence of Antarctic blue whale calls off the Antarctic continent suggests that Antarcticas’ coastal polynyas, i.e. patches of open water where animals can surface to breathe, may provide important habitats for animals to overwinter in high latitude waters.



Item Type
Conference (Talk)
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Primary Division
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Peer revision
Peer-reviewed
Publication Status
Published
Event Details
20th Biennial Conference on Marine Mammals, 09 Dec 2013 - 13 Dec 2013, Dunedin, New Zealand.
Eprint ID
34680
Cite as
Thomisch, K. , Boebel, O. , Clark, C. W. , Spiesecke, S. and van Opzeeland, I. (2013): Spatio-temporal patterns of Antarctic blue whale (Balaenoptera musculus intermedia) vocal behavior in the Weddell Sea , 20th Biennial Conference on Marine Mammals, Dunedin, New Zealand, 9 December 2013 - 13 December 2013 .


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