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Journal article
Uncertainty remains for white sharks in South Africa, as population stability and redistribution cannot be concluded by Bowlby et al. (2023): “Decline or shifting distribution? a first regional trend assessment for white sharks (Carcharodon carcharias) in South Africa”
Ecological indicators, Vol.160, 111810
2024
Abstract
Bowlby et al. (2023) assessed spatio-temporal trends in South Africa’s white shark (Carcharodon carcharias) population using a range of different proxies of white shark occurrence. The authors concluded that, despite significant declines in white shark sightings in several historical aggregation sites, the population as a whole has remained relatively stable throughout South Africa since its protection in 1991. The study also suggests a population redistribution eastward, likely driven by natural predator–prey dynamics (i.e., predation and related risk from orcas, Orcinus orca). Here, we highlight several issues with the methods and the inferences made in that study and argue that the data, as currently analysed and interpreted, cannot support population stability, or redistribution, of South Africa’s white sharks. We also point out that the onset of the decline of white sharks at historical aggregation sites began before the documented appearance of specialist shark-eating orcas (the main alleged cause of the decline put forward in Bowlby et al. 2023). Our concern is that unsupported claims of population stability could jeopardize conservation actions urgently needed for white sharks, if the declines documented at their historical aggregations are representative of the population trend. Below we summarize our arguments.
Details
- Title
- Uncertainty remains for white sharks in South Africa, as population stability and redistribution cannot be concluded by Bowlby et al. (2023): “Decline or shifting distribution? a first regional trend assessment for white sharks (Carcharodon carcharias) in South Africa”
- Authors/Creators
- Enrico Gennari - South African Institute for Aquatic BiodiversityNeil Hammerschlag - University of MiamiSara Andreotti - Stellenbosch UniversityChris Fallows - Apex Shark Expeditions, Wharf St, Simon’s Town, Cape Town 7975, South AfricaMonique Fallows - Apex Shark Expeditions, Wharf St, Simon’s Town, Cape Town 7975, South AfricaMatias Braccini - Murdoch University
- Publication Details
- Ecological indicators, Vol.160, 111810
- Publisher
- Elsevier Ltd
- Identifiers
- 991005645769107891
- Copyright
- © 2024 The Authors.
- Murdoch Affiliation
- Centre for Sustainable Aquatic Ecosystems; School of Environmental and Conservation Sciences
- Language
- English
- Resource Type
- Journal article
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