Uploaded August 2025 | Updated September 2026, 1 hour ago
Robyn Daniels
Abstract Title: Interannual Variability of the Acoustic Occurrence of Killer Whales Around the Prince Edward Islands
Co-Authors: Fannie Shabangu; Tarron Lamont
Author affiliations: Fisheries Management Branch, Department of Forestry, Fisheries and the Environment, Foreshore, Cape Town, South Africa Mammal Research Institute, University of Pretoria, Private Bag X20, Hatfield, Pretoria 0028, South Africa; Department of Oceanography, and Nansen–Tutu Centre for Marine Environmental Research, University of Cape Town, Cape Town, South Africa Oceans and Coasts Research Branch, Department of Forestry, Fisheries and the Environment, Foreshore, Cape Town, South Africa Bayworld Centre for Research and Education, Cape Town, South Africa
Abstract: Killer whales are apex predators in the marine environment with a diverse diet ranging from fish to birds and other marine mammals. They therefore have the potential to affect ecosystem structure and function on multiple trophic levels. They have varying temporal and spatial distributions throughout the oceans. In the waters surrounding the remote sub-Antarctic Prince Edward Islands (PEIs) in the Southern Ocean, a small population of killer whales consisting of 54 unique individuals were observed to be at their maximum abundance during the breeding season of their prey (September to December). Their prey utilise the PEIs for breeding purposes and are suggested to be susceptible to climate change as the sub-Antarctic region is threatened by changing environmental conditions. It is therefore of the utmost importance to close the knowledge gaps of the environmental influence on killer whale population dynamics as they are fundamental ecosystem engineers. Through the use of passive acoustic monitoring (PAM), we can overcome logistical challenges (observing in remote areas or in harsh conditions) and fill in the knowledge gaps of killer whale ecology and behaviour which are typically understudied in the Southern Hemisphere in general. The objective of this study was therefore to describe the killer whale acoustic call types/patterns and compare it to environmental conditions around the PEIs over a 3-year period (mid-2021 to early 2024). This will also be compared to prey abundance, southern elephant seals specifically, and corroborated with killer whale visual sightings. Random forest modelling will be utilised to perform statistical analyses. This will provide us with an indication of the interannual environment variability influences on their feeding, travelling and social behaviour of these apex predators and its potential implications for the ecosystem around the islands. This knowledge is important for understanding killer whale ecology and adaptation to the changing oceans.
Robyn Daniels
Abstract Title: Interannual Variability of the Acoustic Occurrence of Killer Whales Around the Prince Edward Islands
Co-Authors: Fannie Shabangu; Tarron Lamont
Author affiliations: Fisheries Management Branch, Department of Forestry, Fisheries and the Environment, Foreshore, Cape Town, South Africa Mammal Research Institute, University of Pretoria, Private Bag X20, Hatfield, Pretoria 0028, South Africa; Department of Oceanography, and Nansen–Tutu Centre for Marine Environmental Research, University of Cape Town, Cape Town, South Africa Oceans and Coasts Research Branch, Department of Forestry, Fisheries and the Environment, Foreshore, Cape Town, South Africa Bayworld Centre for Research and Education, Cape Town, South Africa
Abstract: Killer whales are apex predators in the marine environment with a diverse diet ranging from fish to birds and other marine mammals. They therefore have the potential to affect ecosystem structure and function on multiple trophic levels. They have varying temporal and spatial distributions throughout the oceans. In the waters surrounding the remote sub-Antarctic Prince Edward Islands (PEIs) in the Southern Ocean, a small population of killer whales consisting of 54 unique individuals were observed to be at their maximum abundance during the breeding season of their prey (September to December). Their prey utilise the PEIs for breeding purposes and are suggested to be susceptible to climate change as the sub-Antarctic region is threatened by changing environmental conditions. It is therefore of the utmost importance to close the knowledge gaps of the environmental influence on killer whale population dynamics as they are fundamental ecosystem engineers. Through the use of passive acoustic monitoring (PAM), we can overcome logistical challenges (observing in remote areas or in harsh conditions) and fill in the knowledge gaps of killer whale ecology and behaviour which are typically understudied in the Southern Hemisphere in general. The objective of this study was therefore to describe the killer whale acoustic call types/patterns and compare it to environmental conditions around the PEIs over a 3-year period (mid-2021 to early 2024). This will also be compared to prey abundance, southern elephant seals specifically, and corroborated with killer whale visual sightings. Random forest modelling will be utilised to perform statistical analyses. This will provide us with an indication of the interannual environment variability influences on their feeding, travelling and social behaviour of these apex predators and its potential implications for the ecosystem around the islands. This knowledge is important for understanding killer whale ecology and adaptation to the changing oceans.
