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Teske PR, Emami-Khoyi A, Golla TR, Sandoval-Castillo J, Lamont T, Chiazzari B, McQuaid CD, Beheregaray LB, van der Lingen CD. The sardine run in southeastern Africa is a mass migration into an ecological trap. SCIENCE ADVANCES 2021; 7:eabf4514. [PMID: 34524856 PMCID: PMC8443171 DOI: 10.1126/sciadv.abf4514] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The KwaZulu-Natal sardine run, popularly known as the “greatest shoal on Earth,” is a mass migration of South African sardines from their temperate core range into the subtropical Indian Ocean. It has been suggested that this represents the spawning migration of a distinct subtropical stock. Using genomic and transcriptomic data from sardines collected around the South African coast, we identified two stocks, one cool temperate (Atlantic) and the other warm temperate (Indian Ocean). Unexpectedly, we found that sardines participating in the sardine run are primarily of Atlantic origin and thus prefer colder water. These sardines separate from the warm-temperate stock and move into temporarily favorable Indian Ocean habitat during brief cold-water upwelling periods. Once the upwelling ends, they find themselves trapped in physiologically challenging subtropical habitat and subject to intense predation pressure. This makes the sardine run a rare example of a mass migration that has no apparent fitness benefits.
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Affiliation(s)
- Peter R. Teske
- Centre for Ecological Genomics and Wildlife Conservation, Department of Zoology, University of Johannesburg, Auckland Park 2006, South Africa
- Corresponding author.
| | - Arsalan Emami-Khoyi
- Centre for Ecological Genomics and Wildlife Conservation, Department of Zoology, University of Johannesburg, Auckland Park 2006, South Africa
| | - Tirupathi R. Golla
- Centre for Ecological Genomics and Wildlife Conservation, Department of Zoology, University of Johannesburg, Auckland Park 2006, South Africa
| | - Jonathan Sandoval-Castillo
- Molecular Ecology Lab, College of Science and Engineering, Flinders University, Adelaide, SA 5042, Australia
| | - Tarron Lamont
- Oceans and Coasts, Department of Forestry, Fisheries and the Environment, P.O. Box 52126, Victoria and Alfred Waterfront, Cape Town 8002, South Africa
- Department of Oceanography, University of Cape Town, Private Bag X3, Rondebosch 7700, South Africa
| | - Brent Chiazzari
- Oceanographic Research Institute, P.O. Box 10712, Marine Parade, Durban 4056, South Africa
| | | | - Luciano B. Beheregaray
- Molecular Ecology Lab, College of Science and Engineering, Flinders University, Adelaide, SA 5042, Australia
| | - Carl D. van der Lingen
- Fisheries Management, Department of Forestry, Fisheries and the Environment, Private Bag X2, Vlaeberg 8012, South Africa
- Department of Biological Sciences and Marine Research Institute, University of Cape Town, Private Bag X3, Rondebosch 7700, South Africa
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