Diverse baleen whale acoustic occurrence around two sub-Antarctic islands: A tale of residents and visitors

Fannie W Shabangu; Tessa Munoz; Lora Van Uffelen; Bobbi J Estabrook; Dawit Yemane; Kathleen M Stafford; Trevor A Branch; Els Vermeulen; Marcel A van den Berg; Tarron Lamont

doi:10.1038/s41598-024-72696-2

Diverse baleen whale acoustic occurrence around two sub-Antarctic islands: A tale of residents and visitors

Sci Rep. 2024 Sep 17;14(1):21663. doi: 10.1038/s41598-024-72696-2.

Authors

Fannie W Shabangu^{1

2}, Tessa Munoz^{3

4}, Lora Van Uffelen³, Bobbi J Estabrook⁵, Dawit Yemane⁶, Kathleen M Stafford⁷, Trevor A Branch⁸, Els Vermeulen⁹, Marcel A van den Berg¹⁰, Tarron Lamont^{10

11

12

13}

Affiliations

¹ Fisheries Management Branch, Department of Forestry, Fisheries and the Environment, Foreshore, Cape Town, South Africa. fannie.shabangu@yahoo.com.
² Mammal Research Institute Whale Unit, University of Pretoria, Private Bag X20, Hatfield, 0028, Pretoria, South Africa. fannie.shabangu@yahoo.com.
³ Department of Ocean Engineering, University of Rhode Island, Narragansett, RI, 02882, USA.
⁴ Applied Ocean Sciences, 5242 Port Royal Road #1032, Springfield, VA, 22151, USA.
⁵ K. Lisa Yang Center for Conservation Bioacoustics, Cornell Lab of Ornithology, Cornell University, Ithaca, NY, 14850, USA.
⁶ Fisheries Management Branch, Department of Forestry, Fisheries and the Environment, Foreshore, Cape Town, South Africa.
⁷ Marine Mammal Institute, Oregon State University, Newport, OR, USA.
⁸ School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA, 98195, USA.
⁹ Mammal Research Institute Whale Unit, University of Pretoria, Private Bag X20, Hatfield, 0028, Pretoria, South Africa.
¹⁰ Oceans and Coasts Research Branch, Department of Forestry, Fisheries and the Environment, Foreshore, Cape Town, South Africa.
¹¹ Department of Oceanography, University of Cape Town, Cape Town, South Africa.
¹² Nansen-Tutu Centre for Marine Environmental Research, University of Cape Town, Cape Town, South Africa.
¹³ Bayworld Centre for Research and Education, Cape Town, South Africa.

Abstract

Knowledge on the occurrence and behaviour of baleen whales around sub-Antarctic regions is limited, and usually based on short, seasonal sighting research from shore or research vessels and whaling records, neither of which provide accurate and comprehensive year-round perspectives of these animals' ecology. We investigated the seasonal acoustic occurrence and diel vocalizing pattern of baleen whales around the sub-Antarctic Prince Edward Islands (PEIs) using passive acoustic monitoring data from mid-2021 to mid-2023, detecting six distinct baleen whale songs from Antarctic blue whales, Madagascan pygmy blue whales, fin whales, Antarctic minke whales, humpback whales, and sei whales. Antarctic blue and fin whales were detected year-round whereas the other species' songs were detected seasonally, including a new Antarctic minke whale bio-duck song sub-type described here for the first time. Antarctic minke and sei whales were more vocally active at night-time whereas the other species had no clear diel vocalizing patterns. Random forest models identified month and/or sea surface temperature as the most important predictors of all baleen whale acoustic occurrence. These novel results highlight the PEIs as a useful habitat for baleen whales given the number of species that inhabit or transit through this region.

Keywords: Feeding ground; Overwintering ground; Passive acoustic monitoring; Southern Ocean; Stopover spot; Year-round habitat.

MeSH terms

Acoustics*
Animals
Antarctic Regions
Ecosystem
Islands
Seasons*
Vocalization, Animal* / physiology
Whales* / physiology