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.

了解幼虫的连通性模式对于海洋空间规划至关重要，特别是对于设计海洋保护区和管理渔业而言。幼虫扩散和连通性的模式可以从大时空尺度的数值运输模型中推断出来。我们评估了西南印度洋（SWIO）海山与毛里求斯，留尼汪岛，马达加斯加，莫桑比克和南非的沿海生态系统之间基于模型的连通性模式，重点是三个浅海山（LaPérouse[LP]，MAD-Ridge [MR]和Walters Shoal [WS]）。使用漂流轨迹和鱼鳞浮游生物扩散的拉格朗日模型，我们表明，幼虫可以进行很长的扩散，幼虫距离随着上层幼虫持续时间（PLD）的增加而增加。有三组更高的连接性：马达加斯加，毛里求斯和拉留尼翁岛东海岸之间的地区；西南印第安海岭的海山；以及由WS和附近的一个未命名海山组成的对。仅在检查时间最长的PLD（360 d）中，这三组之间的连通性才很明显。从海山到沿海生态系统的连通性很弱，最多有2％的幼体来自海山到达沿海生态系统。在三个保持性最强的海山（WS），考虑的最短PLD（15 d），三个焦点海山（LP，MR和WS）的局部滞留峰值约为11％，并随着PLD的增加而急剧下降。MR和LP收集的有关PLD和幼虫年龄的信息用于评估其推测来源。这些幼虫很可能是自我招募的，但也有可能是它们从附近的沿海地区移民而来，即