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 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. At four island locations surrounding the Exuma Sound, Bahamas, including a long-established marine reserve, we collected 3,278 bicolor damselfish (Stegastes partitus) and genotyped them at 10 microsatellite loci. Using Bayesian parentage analysis, we identified eight parent-offspring pairs that directly documented dispersal distances ranging from 0 km (i.e., self-recruitment) to 129 km between local populations (i.e., larval connectivity). More observations of self-recruitment (n=5) were detected than connectivity between islands (n=3). Additionally, we detected spatial and temporal variation in signatures of sweepstakes and Wahlund effects, which may contribute reduced connectivity between populations. 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. Incorporating this large variance in reproductive success into marine metapopulation theory will improve the effectiveness of marine conservation and management by accounting for fluctuations in larval supply.

许多海洋生物在浮游幼体阶段可被输送数百公里，但学界对幼体扩散的时空格局仍知之甚少。尽管种群遗传学工具可用于推断进化时间尺度下的幼体移动规律，但较大的有效种群规模与高频基因流，为在更短的、具有生态学意义的时间尺度上记录幼体扩散格局带来了严峻挑战。本研究通过结合四年间的直接亲本分析与间接遗传分析，对一种常见珊瑚礁鱼类的幼体扩散时空格局展开记录，以此解决上述难题。我们在巴哈马埃克苏马湾周边的四个岛屿点位（包含一处长期设立的海洋保护区（marine reserve））采集了3278尾双色雀鲷（Stegastes partitus），并对其10个微卫星位点（microsatellite loci）进行基因分型。通过贝叶斯亲本分析（Bayesian parentage analysis），我们共鉴定出8组亲子对，直接证实了本地种群间的幼体扩散距离范围为0公里（即自我补充（self-recruitment））至129公里（即幼体连通性（larval connectivity））。自我补充的观测案例（n=5）多于岛屿间连通性的观测案例（n=3）。此外，我们检测到抽奖式繁殖效应与瓦隆德效应（Wahlund effect）的特征存在时空变异，这可能会降低种群间的连通性。我们观测到的繁殖成功率高方差（即"抽奖式繁殖"）可能受到埃克苏马湾内季节性中尺度涡旋（mesoscale gyres）的影响，此类涡旋对塑造区域海洋环流格局具有重要作用。将这种高繁殖成功率方差纳入海洋集合种群（marine metapopulation）理论，可通过纳入幼体供应的波动，提升海洋保护与管理工作的实效。