Crochelet Estelle auteur aut IRD Barrier Nicolas auteur aut IRD Andrello M. auteur aut IRD Marsac Francis auteur aut IRD Spadone A. auteur aut IRD Lett Christophe auteur aut IRD text journalArticle eng text/pdf born digital access Understanding larval connectivity patterns is critical for marine spatial planning, particularly for designing marine protected areas and managing fisheries. Patterns of larval dispersal and connectivity can be inferred from numerical transport models at large spatial and temporal scales. We assess model-based connectivity patterns between seamounts of the Southwestern Indian Ocean (SWIO) and the coastal ecosystems of Mauritius, La Reunion, Madagascar, Mozambique and South Africa, with emphasis on three shallow seamounts (La Perouse [LP], MAD-Ridge [MR] and Walters Shoal [WS]). Using drifter trajectory and a Lagrangian model of ichthyo-plankton dispersal, we show that larvae can undertake very long dispersion, with larval distances increasing with pelagic larval duration (PLD). There are three groups of greater connectivity: the region between the eastern coast of Madagascar, Mauritius and La Reunion islands; the seamounts of the South West Indian Ridge; and the pair formed by WS and a nearby un-named seamount. Connectivity between these three groups is evident only for the longest PLD examined (360 d). Connectivity from seamounts to coastal ecosystems is weak, with a maximum of 2% of larvae originating from seamounts reaching coastal ecosystems. Local retention at the three focal seamounts (LP, MR and WS) peaks at about 11% for the shortest PLD considered (15 d) at the most retentive seamount (WS) and decreases sharply with increasing PLD. Information on PLD and age of larvae collected at MR and LP are used to assess their putative origin. These larvae are likely self-recruits but it is also plausible that they immigrate from nearby coastal sites, i.e. the southern coast of Madagascar for MR and the islands of La Reunion and Mauritius for LP. specialized Seamounts Connectivity Larval duration Larval drift Lagrangian modelling Biophysical model Surface drifters Southwestern indian ocean Ichthyop OCEAN INDIEN MADAGASCAR REUNION MAURICE MOZAMBIQUE AFRIQUE DU SUD 030 034 036 020 Payne A. ed. edt IRD Roberts M. ed. edt IRD Marsac Francis ed. edt IRD Noyon M. ed. edt IRD Ternon Jean-François ed. edt IRD 176 No spécial art. 104774 [18 ] 2020 0967-0645 https://www.documentation.ird.fr/hor/fdi:010079444 10.1016/j.dsr2.2020.104774 0967-0645 [F B010079444] https://www.documentation.ird.fr/hor/fdi:010079444 https://www.documentation.ird.fr/intranet/publi/2020/08/010079444.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2020-09-17 2025-02-24 fdi:010079444 fre