Seasonal patterns in humpback whale acoustic behavior in the Southern Ocean
Evidence of off-season humpback whale (Megaptera novaeangliae) acoustic presence in high latitude feeding areas is accumulating for Northern Hemisphere waters. To date, however, long-term studies investigating humpback whale vocal behavior in the Southern Ocean were limited to the coastal region. Th...
| Main Authors: | , , , |
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| Format: | Conference Object |
| Language: | unknown |
| Published: |
2017
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| Subjects: | |
| Online Access: | https://epic.awi.de/id/eprint/44818/ https://hdl.handle.net/10013/epic.51066 |
| Summary: | Evidence of off-season humpback whale (Megaptera novaeangliae) acoustic presence in high latitude feeding areas is accumulating for Northern Hemisphere waters. To date, however, long-term studies investigating humpback whale vocal behavior in the Southern Ocean were limited to the coastal region. This study provides preliminary baseline data from three recording sites on humpback whale vocal behavior on Antarctic feeding grounds. Passive acoustic recorders were located in a transect along the Greenwich meridian at 59’S (SV0002), at 64’S (SV1000) and 66’S (SV1001). Humpback whales were acoustically present from January to August (SV0002), from January to June (SV1000) and from January until May (SV1001). Acoustic presence was most pronounced (>60% of recording days containing calls) from May to July (SV0002), and April to May (SV1000 and SV1001), concurring with substantial increases in ice cover (>90%) at all three sites. During the period of ice formation (February to April) acoustic presence was sparser. Calls were divided into 27 call categories with a maximum of 10 subtypes per category. For all three recorders 4 to 8 call categories made up <80% of all calls, 3 call categories of which where the same for all three recorders. The vocal repertoire was more diverse in March, April and May compared to January, February, June, July and August in all three recorders. Furthermore, humpback whale song was present at all 3 recording sites, at SV0002 in May and June, SV1000 in March and SV1001 in April. This study demonstrates that pervasive humpback whale presence in the Southern Ocean is not limited to the coast, but extends to pelagic regions. The presence of social sounds and song during extended periods suggests that whales were not just transiting the area, but roamed the area for some time, possibly to exploit the presence of local food patches and open water. |
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