Year-round acoustic monitoring of Antarctic blue and fin whales in relation to environmental conditions off the west coast of South Africa
Antarctic blue and fin whales were once abundant in the southeastern Atlantic Ocean, yet their occurrence and ecology in this region is still poorly understood. Seasonal acoustic occurrence and behaviour of Antarctic blue and fin whales off the South African west coast were determined using bio-acou...
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Online Access: | https://doi.org/10.1007/s00227-022-04026-x https://repository.up.ac.za/handle/2263/89335 |
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ftunivpretoria:oai:repository.up.ac.za:2263/89335 2023-06-11T04:07:11+02:00 Year-round acoustic monitoring of Antarctic blue and fin whales in relation to environmental conditions off the west coast of South Africa Letsheleha, Ishmail S. Shabangu, Fannie Welcome Farrell, Dara Andrew, Rex K. La Grange, Philip L. Findlay, Kenneth Pierce 2022-02 application/pdf https://doi.org/10.1007/s00227-022-04026-x https://repository.up.ac.za/handle/2263/89335 en eng Springer Letsheleha, I.S., Shabangu, F.W., Farrell, D. et al. Year-round acoustic monitoring of Antarctic blue and fin whales in relation to environmental conditions off the west coast of South Africa. Marine Biology 169, 41 (2022). https://doi.org/10.1007/s00227-022-04026-x. 0025-3162 (print) 1432-1793 (online) doi:10.1007/s00227-022-04026-x https://repository.up.ac.za/handle/2263/89335 © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2022. The original publication is available at : http://link.springer.comjournal/227. Antarctic blue whale (Balaenoptera musculus intermedia) Fin whale calls Diel calling behaviour Seasonal occurrence Southeast Atlantic Ocean Passive acoustic monitoring Postprint Article 2022 ftunivpretoria https://doi.org/10.1007/s00227-022-04026-x 2023-05-02T00:24:34Z Antarctic blue and fin whales were once abundant in the southeastern Atlantic Ocean, yet their occurrence and ecology in this region is still poorly understood. Seasonal acoustic occurrence and behaviour of Antarctic blue and fin whales off the South African west coast were determined using bio-acoustic data collected through two autonomous acoustic recorders between December 2015 and January 2017. Blue whale Z-calls were detected year-round with a peak in July, while fin whale 20 Hz pulses were detected seasonally with a peak in June by a recorder deployed at 1118 m water depth. Blue and fin whale calls were detected seasonally with a similar peak in May by a recorder deployed at 4481 m water depth. The blue whale 27 Hz chorus, and blue and fin whale 18–28 Hz chorus followed a similar trend as the seasonal acoustic occurrence of individual Z-calls and 20 Hz pulses. A maximum detection range of 800 km estimated by acoustic propagation modelling suggests that detected calls originate from whales within the South African west coast waters. Random forest models classified month of the year, wind speed, log-transformed chlorophyll-a, and sea surface temperature anomaly as the most important predictors of blue and fin whale acoustic occurrence and behaviour. Our study highlights the South African west coast as an important year-round habitat and seasonal breeding or overwintering habitat of these whales. Additionally, the year-round acoustic occurrence in this region supports the notion that blue whale migration patterns are more dynamic than previously perceived. The National Research Foundation and the South African National Antarctic Programme. https://link.springer.com/journal/227 hj2023 Mammal Research Institute Article in Journal/Newspaper Antarc* Antarctic Balaenoptera musculus Blue whale Fin whale South African National Antarctic Programme University of Pretoria: UPSpace Antarctic Marine Biology 169 3 |
institution |
Open Polar |
collection |
University of Pretoria: UPSpace |
op_collection_id |
ftunivpretoria |
language |
English |
topic |
Antarctic blue whale (Balaenoptera musculus intermedia) Fin whale calls Diel calling behaviour Seasonal occurrence Southeast Atlantic Ocean Passive acoustic monitoring |
spellingShingle |
Antarctic blue whale (Balaenoptera musculus intermedia) Fin whale calls Diel calling behaviour Seasonal occurrence Southeast Atlantic Ocean Passive acoustic monitoring Letsheleha, Ishmail S. Shabangu, Fannie Welcome Farrell, Dara Andrew, Rex K. La Grange, Philip L. Findlay, Kenneth Pierce Year-round acoustic monitoring of Antarctic blue and fin whales in relation to environmental conditions off the west coast of South Africa |
topic_facet |
Antarctic blue whale (Balaenoptera musculus intermedia) Fin whale calls Diel calling behaviour Seasonal occurrence Southeast Atlantic Ocean Passive acoustic monitoring |
description |
Antarctic blue and fin whales were once abundant in the southeastern Atlantic Ocean, yet their occurrence and ecology in this region is still poorly understood. Seasonal acoustic occurrence and behaviour of Antarctic blue and fin whales off the South African west coast were determined using bio-acoustic data collected through two autonomous acoustic recorders between December 2015 and January 2017. Blue whale Z-calls were detected year-round with a peak in July, while fin whale 20 Hz pulses were detected seasonally with a peak in June by a recorder deployed at 1118 m water depth. Blue and fin whale calls were detected seasonally with a similar peak in May by a recorder deployed at 4481 m water depth. The blue whale 27 Hz chorus, and blue and fin whale 18–28 Hz chorus followed a similar trend as the seasonal acoustic occurrence of individual Z-calls and 20 Hz pulses. A maximum detection range of 800 km estimated by acoustic propagation modelling suggests that detected calls originate from whales within the South African west coast waters. Random forest models classified month of the year, wind speed, log-transformed chlorophyll-a, and sea surface temperature anomaly as the most important predictors of blue and fin whale acoustic occurrence and behaviour. Our study highlights the South African west coast as an important year-round habitat and seasonal breeding or overwintering habitat of these whales. Additionally, the year-round acoustic occurrence in this region supports the notion that blue whale migration patterns are more dynamic than previously perceived. The National Research Foundation and the South African National Antarctic Programme. https://link.springer.com/journal/227 hj2023 Mammal Research Institute |
format |
Article in Journal/Newspaper |
author |
Letsheleha, Ishmail S. Shabangu, Fannie Welcome Farrell, Dara Andrew, Rex K. La Grange, Philip L. Findlay, Kenneth Pierce |
author_facet |
Letsheleha, Ishmail S. Shabangu, Fannie Welcome Farrell, Dara Andrew, Rex K. La Grange, Philip L. Findlay, Kenneth Pierce |
author_sort |
Letsheleha, Ishmail S. |
title |
Year-round acoustic monitoring of Antarctic blue and fin whales in relation to environmental conditions off the west coast of South Africa |
title_short |
Year-round acoustic monitoring of Antarctic blue and fin whales in relation to environmental conditions off the west coast of South Africa |
title_full |
Year-round acoustic monitoring of Antarctic blue and fin whales in relation to environmental conditions off the west coast of South Africa |
title_fullStr |
Year-round acoustic monitoring of Antarctic blue and fin whales in relation to environmental conditions off the west coast of South Africa |
title_full_unstemmed |
Year-round acoustic monitoring of Antarctic blue and fin whales in relation to environmental conditions off the west coast of South Africa |
title_sort |
year-round acoustic monitoring of antarctic blue and fin whales in relation to environmental conditions off the west coast of south africa |
publisher |
Springer |
publishDate |
2022 |
url |
https://doi.org/10.1007/s00227-022-04026-x https://repository.up.ac.za/handle/2263/89335 |
geographic |
Antarctic |
geographic_facet |
Antarctic |
genre |
Antarc* Antarctic Balaenoptera musculus Blue whale Fin whale South African National Antarctic Programme |
genre_facet |
Antarc* Antarctic Balaenoptera musculus Blue whale Fin whale South African National Antarctic Programme |
op_relation |
Letsheleha, I.S., Shabangu, F.W., Farrell, D. et al. Year-round acoustic monitoring of Antarctic blue and fin whales in relation to environmental conditions off the west coast of South Africa. Marine Biology 169, 41 (2022). https://doi.org/10.1007/s00227-022-04026-x. 0025-3162 (print) 1432-1793 (online) doi:10.1007/s00227-022-04026-x https://repository.up.ac.za/handle/2263/89335 |
op_rights |
© The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2022. The original publication is available at : http://link.springer.comjournal/227. |
op_doi |
https://doi.org/10.1007/s00227-022-04026-x |
container_title |
Marine Biology |
container_volume |
169 |
container_issue |
3 |
_version_ |
1768380029711941632 |