Larval anchovy and sardine dispersal patterns in South Africa’s exclusive economic zone
Lagrangian dispersal models are valuable tools for understanding the transport mechanisms and distribution of larvae in space and time. These models primarily use high-quality physical oceanographic data from hydrodynamic ocean models to simulate the advection and connecting pathways of larvae. The...
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Frontiers Media S.A.
2025-02-01
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| Series: | Frontiers in Marine Science |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fmars.2024.1508479/full |
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| author | Tshikana Rasehlomi Tshikana Rasehlomi Marjolaine Krug Marjolaine Krug Mari S. Myksvoll Mari S. Myksvoll |
| author_facet | Tshikana Rasehlomi Tshikana Rasehlomi Marjolaine Krug Marjolaine Krug Mari S. Myksvoll Mari S. Myksvoll |
| author_sort | Tshikana Rasehlomi |
| collection | DOAJ |
| description | Lagrangian dispersal models are valuable tools for understanding the transport mechanisms and distribution of larvae in space and time. These models primarily use high-quality physical oceanographic data from hydrodynamic ocean models to simulate the advection and connecting pathways of larvae. The paper seeks to achieve the following objectives 1) to establish the dispersal patterns of larval anchovies and sardines spawned in South Africa’s coastal marine protected areas (i.e., inshore of the 200 m isobath), and 2) to assess the impact of model resolution on the dispersal patterns by comparing outputs of a 3-km-grid coastal and regional ocean community model, and the 8-km-grid global ocean physics reanalysis product. We demonstrate that the model yields more structured patterns than sporadic patterns obtained from the global reanalysis. The model shows relatively shorter residence times (i.e., < 5 days) and transport confined to the inshore area of the Agulhas Current. The high variability of dispersals observed off the west coast is attributable to the significant differences in mean kinetic energy between the model and global reanalysis. This finding directly impacts transport and potential connectivity along coastlines: global reanalysis data overestimated local retention and subsequent recruitment variability. Our findings indicate that a model grid size of 3 km or smaller may be more appropriate for studying the dispersal patterns of anchovies and sardines in the South African coastal zone. These findings add to the growing knowledge of the importance of including sub-mesoscale processes in Lagrangian analysis for dispersal studies of coastal species. |
| format | Article |
| id | doaj-art-632451b265374c049963677328d1e121 |
| institution | Kabale University |
| issn | 2296-7745 |
| language | English |
| publishDate | 2025-02-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Marine Science |
| spelling | doaj-art-632451b265374c049963677328d1e1212025-02-06T05:21:51ZengFrontiers Media S.A.Frontiers in Marine Science2296-77452025-02-011110.3389/fmars.2024.15084791508479Larval anchovy and sardine dispersal patterns in South Africa’s exclusive economic zoneTshikana Rasehlomi0Tshikana Rasehlomi1Marjolaine Krug2Marjolaine Krug3Mari S. Myksvoll4Mari S. Myksvoll5Department of Forestry, Fisheries and the Environment, Oceans & Coasts, South AfricaNansen-Tutu Center for Marine Environmental Research, Department of Oceanography, University of Cape Town, Cape Town, South AfricaDepartment of Forestry, Fisheries and the Environment, Oceans & Coasts, South AfricaNansen-Tutu Center for Marine Environmental Research, Department of Oceanography, University of Cape Town, Cape Town, South AfricaNansen-Tutu Center for Marine Environmental Research, Department of Oceanography, University of Cape Town, Cape Town, South AfricaInstitute of Marine Research, Bergen, NorwayLagrangian dispersal models are valuable tools for understanding the transport mechanisms and distribution of larvae in space and time. These models primarily use high-quality physical oceanographic data from hydrodynamic ocean models to simulate the advection and connecting pathways of larvae. The paper seeks to achieve the following objectives 1) to establish the dispersal patterns of larval anchovies and sardines spawned in South Africa’s coastal marine protected areas (i.e., inshore of the 200 m isobath), and 2) to assess the impact of model resolution on the dispersal patterns by comparing outputs of a 3-km-grid coastal and regional ocean community model, and the 8-km-grid global ocean physics reanalysis product. We demonstrate that the model yields more structured patterns than sporadic patterns obtained from the global reanalysis. The model shows relatively shorter residence times (i.e., < 5 days) and transport confined to the inshore area of the Agulhas Current. The high variability of dispersals observed off the west coast is attributable to the significant differences in mean kinetic energy between the model and global reanalysis. This finding directly impacts transport and potential connectivity along coastlines: global reanalysis data overestimated local retention and subsequent recruitment variability. Our findings indicate that a model grid size of 3 km or smaller may be more appropriate for studying the dispersal patterns of anchovies and sardines in the South African coastal zone. These findings add to the growing knowledge of the importance of including sub-mesoscale processes in Lagrangian analysis for dispersal studies of coastal species.https://www.frontiersin.org/articles/10.3389/fmars.2024.1508479/fullmarine protected areasLagrangian analysisdispersionconnectivityocean modelSouth Africa |
| spellingShingle | Tshikana Rasehlomi Tshikana Rasehlomi Marjolaine Krug Marjolaine Krug Mari S. Myksvoll Mari S. Myksvoll Larval anchovy and sardine dispersal patterns in South Africa’s exclusive economic zone Frontiers in Marine Science marine protected areas Lagrangian analysis dispersion connectivity ocean model South Africa |
| title | Larval anchovy and sardine dispersal patterns in South Africa’s exclusive economic zone |
| title_full | Larval anchovy and sardine dispersal patterns in South Africa’s exclusive economic zone |
| title_fullStr | Larval anchovy and sardine dispersal patterns in South Africa’s exclusive economic zone |
| title_full_unstemmed | Larval anchovy and sardine dispersal patterns in South Africa’s exclusive economic zone |
| title_short | Larval anchovy and sardine dispersal patterns in South Africa’s exclusive economic zone |
| title_sort | larval anchovy and sardine dispersal patterns in south africa s exclusive economic zone |
| topic | marine protected areas Lagrangian analysis dispersion connectivity ocean model South Africa |
| url | https://www.frontiersin.org/articles/10.3389/fmars.2024.1508479/full |
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