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An investigation on humpback whales' distribution in relation to Antarctic sea ice in the IDCR/SOWER dataset
Existing literature has identified humpback whales (Megaptera novaeangliae) as climate sentinels since their feeding ecology is inextricably linked to the oceanic features around Antarctica, and to the seasonal sea ice. The changing Antarctic cryosphere in response to climate change threatens not on...
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| Format: | Thesis |
| Language: | English English |
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Department of Oceanography
2025
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| _version_ | 1867613327506538496 |
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| access_status_str | Open Access |
| author | Mthethwa, Mbali |
| author2 | Vichi, Marcello |
| author_browse | Mthethwa, Mbali Vichi, Marcello |
| author_facet | Vichi, Marcello Mthethwa, Mbali |
| author_sort | Mthethwa, Mbali |
| collection | Thesis |
| description | Existing literature has identified humpback whales (Megaptera novaeangliae) as climate sentinels since their feeding ecology is inextricably linked to the oceanic features around Antarctica, and to the seasonal sea ice. The changing Antarctic cryosphere in response to climate change threatens not only their habitat but also their prey resources. Understanding the interaction between the changing Antarctic Sea ice and its influence on the recovering humpback whales' distribution and behaviour is fundamental. Long-term ecological research offers the potential to understand ecological interactions and variability therein, over time scales relevant to both the life history of the animals and their physical environment. Implemented to assess the effectiveness of the moratorium on baleen whale densities, the IDCR/SOWER dataset is the sole cetacean long-term dataset containing in-depth information about the recent status of all Southern Ocean baleen whales. This study examines the potential utility of this dataset beyond its original scope, specifically assessing how it can contribute to climate research. Using the humpback whale sightings dataset, I prepared a workflow analysis to visually assess the distribution of humpback whales during the IDCR/SOWER surveys in relation to the sea ice from climate data records. The analysis was framed around the use of regional sectors typically used for sea ice research, rather than the feeding areas identified by the International Whaling Commission. The results show that although humpback whales indicate southward expansion as the sea ice retreats, the influence of interannual changes in sea ice on sightings is not uniform, and evident only in a few sectors. Taking into consideration the caveats of using presence/absence whale distribution data, this study represents a significant step forward in demonstrating the potential of this dataset for interdisciplinary research on polar environments beyond its original intention |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/41498 |
| institution | University of Cape Town (South Africa) |
| language | English eng |
| last_indexed | 2026-06-10T12:34:23.309Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2025 |
| publishDateRange | 2025 |
| publishDateSort | 2025 |
| publisher | Department of Oceanography |
| publisherStr | Department of Oceanography |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/41498 An investigation on humpback whales' distribution in relation to Antarctic sea ice in the IDCR/SOWER dataset Mthethwa, Mbali Vichi, Marcello Applied Ocean Sciences Existing literature has identified humpback whales (Megaptera novaeangliae) as climate sentinels since their feeding ecology is inextricably linked to the oceanic features around Antarctica, and to the seasonal sea ice. The changing Antarctic cryosphere in response to climate change threatens not only their habitat but also their prey resources. Understanding the interaction between the changing Antarctic Sea ice and its influence on the recovering humpback whales' distribution and behaviour is fundamental. Long-term ecological research offers the potential to understand ecological interactions and variability therein, over time scales relevant to both the life history of the animals and their physical environment. Implemented to assess the effectiveness of the moratorium on baleen whale densities, the IDCR/SOWER dataset is the sole cetacean long-term dataset containing in-depth information about the recent status of all Southern Ocean baleen whales. This study examines the potential utility of this dataset beyond its original scope, specifically assessing how it can contribute to climate research. Using the humpback whale sightings dataset, I prepared a workflow analysis to visually assess the distribution of humpback whales during the IDCR/SOWER surveys in relation to the sea ice from climate data records. The analysis was framed around the use of regional sectors typically used for sea ice research, rather than the feeding areas identified by the International Whaling Commission. The results show that although humpback whales indicate southward expansion as the sea ice retreats, the influence of interannual changes in sea ice on sightings is not uniform, and evident only in a few sectors. Taking into consideration the caveats of using presence/absence whale distribution data, this study represents a significant step forward in demonstrating the potential of this dataset for interdisciplinary research on polar environments beyond its original intention 2025-06-30T13:12:09Z 2025-06-30T13:12:09Z 2025 2025-06-30T13:00:08Z Thesis / Dissertation Masters MSc http://hdl.handle.net/11427/41498 en eng application/pdf Department of Oceanography Faculty of Science University of Cape Town |
| spellingShingle | Applied Ocean Sciences Mthethwa, Mbali An investigation on humpback whales' distribution in relation to Antarctic sea ice in the IDCR/SOWER dataset |
| thesis_degree_str | Master's |
| title | An investigation on humpback whales' distribution in relation to Antarctic sea ice in the IDCR/SOWER dataset |
| title_full | An investigation on humpback whales' distribution in relation to Antarctic sea ice in the IDCR/SOWER dataset |
| title_fullStr | An investigation on humpback whales' distribution in relation to Antarctic sea ice in the IDCR/SOWER dataset |
| title_full_unstemmed | An investigation on humpback whales' distribution in relation to Antarctic sea ice in the IDCR/SOWER dataset |
| title_short | An investigation on humpback whales' distribution in relation to Antarctic sea ice in the IDCR/SOWER dataset |
| title_sort | investigation on humpback whales distribution in relation to antarctic sea ice in the idcr sower dataset |
| topic | Applied Ocean Sciences |
| url | http://hdl.handle.net/11427/41498 |
| work_keys_str_mv | AT mthethwambali aninvestigationonhumpbackwhalesdistributioninrelationtoantarcticseaiceintheidcrsowerdataset AT mthethwambali investigationonhumpbackwhalesdistributioninrelationtoantarcticseaiceintheidcrsowerdataset |