TY - JOUR T1 - Connectivity between seamounts and coastal ecosystems in the Southwestern Indian Ocean A1 - Crochelet,Estelle A1 - Barrier,Nicolas A1 - Andrello,Marco A1 - Marsac,Francis A1 - Spadone,Aurélie A1 - Lett,Christophe AD - ARBRE - Agence de Recherche pour la Biodiversité à la Réunion, 34 avenue de la Grande Ourse, 97434, Saint-Gilles, La Réunion, France AD - IRD / ESPACE-DEV (UMR 228), Parc Technologique Universitaire, 2 rue Joseph Wetzell, CS 41 095, 97495, Sainte Clotilde Cedex, La Réunion, France AD - Institut de Recherche pour le Développement (IRD), Sète, France AD - MARBEC, Univ Montpellier, CNRS, Ifremer, IRD, Sète, France AD - IUCN – International Union for Conservation of Nature, Gland, Switzerland UR - https://doi.org/10.1016/j.dsr2.2020.104774 DO - 10.1016/j.dsr2.2020.104774 KW - Seamounts KW - Connectivity KW - Larval duration KW - Larval drift KW - Lagrangian modelling KW - Biophysical model KW - Surface drifters KW - Southwestern indian ocean KW - Ichthyop N2 - 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 Réunion, Madagascar, Mozambique and South Africa, with emphasis on three shallow seamounts (La Pérouse [LP], MAD-Ridge [MR] and Walters Shoal [WS]). Using drifter trajectory and a Lagrangian model of ichthyoplankton 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 Réunion 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 Réunion and Mauritius for LP. Y1 - 2020/06 PB - Elsevier BV JF - Deep-sea Research Part Ii-topical Studies In Oceanography SN - 0967-0645 VL - 176 ID - 72461 ER -