Data from: Spatial and temporal patterns of larval dispersal in a coral-reef fish metapopulation: evidence of variable reproductive success

Many marine organisms can be transported hundreds of kilometers during their pelagic larval stage, yet little is known about spatial and temporal patterns of larval dispersal. Although traditional population-genetic tools can be applied to infer movement of larvae on an evolutionary time scale, large effective population sizes and high rates of gene-flow present serious challenges to documenting dispersal patterns over shorter, ecologically-relevant, time scales. Here, we address these challenges by combining direct parentage analysis and indirect genetic analyses over a four-year period to document spatial and temporal patterns of larval dispersal in a common coral-reef fish: the bicolor damselfish (Stegastes partitus). At four island locations surrounding Exuma Sound, Bahamas, including a long-established marine reserve, we collected 3,278 individuals and genotyped them at 10 microsatellite loci. Using Bayesian parentage analysis, we identified eight parent-offspring pairs, thereby directly documenting dispersal distances ranging from 0 km (i.e., self-recruitment) to 129 km (i.e., larval connectivity). Despite documenting substantial dispersal and gene-flow between islands, we observed more self-recruitment events than expected if the larvae were drawn from a common, well-mixed pool (i.e., a completely open population). Additionally, we detected both spatial and temporal variation in signatures of sweepstakes and Wahlund effects. The high variance in reproductive success (i.e., “sweepstakes”) we observed may be influenced by seasonal mesoscale gyres present in the Exuma Sound, which play a prominent role in shaping local oceanographic patterns. This study documents the complex nature of larval dispersal in a coral-reef fish, and highlights the importance of sampling multiple cohorts and coupling both direct and indirect genetic methods in order disentangle patterns of dispersal, gene-flow, and variable reproductive success.许多海洋生物在浮游幼体阶段可被输送数百公里，但学界对其幼体扩散的时空格局仍知之甚少。尽管传统种群遗传工具可用于推断进化时间尺度下的幼体移动，但较大的有效种群大小与高频基因流（gene flow），为在更短的生态相关时间尺度上记录扩散格局带来了严峻挑战。本研究结合四年间的直接亲权分析与间接遗传分析，以此应对上述挑战，从而解析一种常见珊瑚礁鱼类——双带雀鲷（Stegastes partitus）的幼体扩散时空格局。研究团队在巴哈马埃克苏马海峡周边的4个岛屿点位（含一处长期设立的海洋保护区）采集了3278个个体，并对其10个微卫星位点进行基因分型。通过贝叶斯亲权分析，本研究共鉴定出8组亲子对，直接记录到的扩散距离范围为0公里（即自我补充）至129公里（即幼体连通性）。尽管研究记录到岛屿间存在显著的扩散与基因流，但观测到的自我补充事件数量，多于假设幼体来自单一充分混合种群池（即完全开放种群）时的预期值。此外，本研究还检测到抽奖式效应（sweepstakes effect）与瓦隆德效应（Wahlund effect）的信号存在时空变异。本研究观测到的繁殖成功率高方差（即"抽奖式繁殖"），可能受到埃克苏马海峡区域季节性中尺度涡旋的影响，该涡旋在塑造局地海洋环流格局中发挥重要作用。本研究阐明了珊瑚礁鱼类幼体扩散的复杂本质，并强调了采样多个同生群、结合直接与间接遗传方法的重要性，以此厘清扩散、基因流与可变繁殖成功率的格局。