Countries in the Western Indian Ocean (WIO) and along the Red Sea are particularly vulnerable to coral reef degradation, and understanding the degree of connectivity among coral reefs is a first step toward efficient conservation. The aim of this study is to investigate the genetic diversity, population structure and connectivity patterns of the broadcast spawning coral Acropora tenuis, first at a large scale comparing the Red Sea and the WIO, and second at a smaller scale comparing sites within the WIO. In total 689 individual A. tenuis colonies were sampled on 28 locations in Saudi Arabia, Kenya, Tanzania, Mozambique and Madagascar and analysed with seven microsatellite markers. The sample site in the Red Sea was found to be differentiated from all other sites in the WIO, which confirms the hypothesised genetic break. High differentiation was found between the African mainland and Madagascar and within Madagascar. However, there is evidence for long-distance larval dispersal for A. tenuis in the North Mozambique Channel region, with exchange between northern Mozambique and northern Madagascar. The sites in the southwest of Madagascar show mixing with sites in northern Madagascar, as well as exchange with sites in northern Mozambique and Tanzania. Southern Mozambique forms a separate group in Bayesian clustering. High genetic connectivity was found for most sites along the East African mainland coast, with no indication for strict genetic barriers. These results support biophysical modelling studies, which propose Tanzania as a seeding source of larvae for downstream Kenya. These patterns of high genetic connectivity combined with contemporary dispersal barriers can be explained by the long larval duration of A. tenuis and the prevailing northbound East African Coast Current that facilitates higher genetic connectivity along the northern East African Coast, while eddies in the Mozambique Channel are causing larval retention in southern Mozambique and Madagascar.
|Original language||English (US)|
|State||Published - Apr 22 2022|
Bibliographical noteKAUST Repository Item: Exported on 2022-05-25
Acknowledgements: We would like to thank the agencies that supported our work: Fonds Wetenschappelijk Onderzoek Vlaanderen (FWO) for the project ‘Connectivity of Coral Reefs and Mangroves in the Western Indian Ocean’ (COCOMA-WIO; grant 1501612N); Vrije Universiteit Brussel (VUB, OZR2068BOF) for financial support; Vlaamse Interuniversitaire—Raad Universitaire Ontwikkelingssamenwerking (VLIR-UOS) for providing a PhD scholarship to H.A. Ratsimbazafy; VLIR-UOS, doctoral school of the VUB, and Leopold III-fonds for providing travel grants to R.M. van der Ven; European Union Erasmus Mundus Programme CARIBU, VLIR-UOS and King Abdullah University for Science and Technology (Saudi Arabia) for providing travel grants to M. Kochzius; T. Sierens (VUB, Belgium) for assistance during laboratory work; L. van Dijk for processing samples; T. Lavitra (Institut Halieutiques et des Sciences Marine, Université de Tuléar, Madagascar), J. M. Mwaura (Kenya Marine and Fisheries Research Institute, Kenya) and B. Cowburn (University of Oxford, UK) for collecting samples; D. De Ryck (VUB, Belgium), F. Huyghe (VUB, Belgium), M.S. Mohammed (State University of Zanzibar, Tanzania), V. Muhala (Eduardo Mondlane University, Mozambique) and M. Berumen (King Abdullah University for Science and Technology) for assistance during fieldwork; M. Sheikh (State University of Zanzibar) for logistical support; the competent authorities in Kenya, Madagascar, Mozambique, Saudi Arabia and Tanzania for permits; N. van Hoytema (Centre for Environment, Fisheries and Aquaculture Science (Cefas), UK) for proofreading.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.
ASJC Scopus subject areas
- Aquatic Science