Data from: Patterns and persistence of larval retention and connectivity in a marine fish metapopulation

Connectivity, the demographic linking of local populations through the dispersal of individuals, is one of the most poorly understood processes in population dynamics, yet has profound implications for conservation and harvest strategies. For marine species with pelagic larvae, direct estimation of connectivity remains logistically challenging and has mostly been limited to single snapshots in time. Here, we document seasonal and interannual patterns of larval dispersal in a metapopulation of the coral reef fish Amphiprion polymnus. A 3-year record of larval trajectories within and among nine discrete local populations from an area of approximately 35 km was established by determining the natal origin of settled juveniles through DNA parentage analysis. We found that spatial patterns of both self-recruitment and connectivity were remarkably consistent over time, with a low level of self-recruitment at the scale of individual sites. Connectivity among sites was common and multidirectional in all years and was not significantly influenced by seasonal variability of predominant surface current directions. However, approximately 75% of the sampled juveniles could not be assigned to parents within the study area, indicating high levels of immigrations from sources outside the study area. The data support predictions that the magnitude and temporal stability of larval connectivity decreases significantly with increasing distance between subpopulations, but increases with the size of subpopulations. Given the considerable effort needed to directly measure larval exchange, the consistent patterns suggest snapshot parentage analyses can provide useful dispersal estimates to inform spatial management decisions.连通性（connectivity）指通过个体扩散实现的局域种群间人口统计学关联，是种群动态研究领域认知最为匮乏的过程之一，但其对物种保护与捕捞策略制定具有深远影响。对于具有浮游幼体的海洋物种而言，直接估算连通性仍面临诸多后勤难题，且过往研究大多仅获取了单一时间节点的观测数据。本研究针对珊瑚礁鱼类侧带双锯鱼（Amphiprion polymnus）的集合种群（metapopulation），阐明了其幼体扩散的季节与年际变化模式。研究通过DNA亲子鉴定分析确定定居幼体的亲本来源，构建了覆盖约35平方公里海域内9个独立局域种群内部及彼此间的幼体运动轨迹的3年观测序列。研究发现，自我补充（self-recruitment）与连通性的空间格局在时间尺度上均表现出显著的稳定性，且单个样地尺度下的自我补充水平较低。各站点间的连通性在所有观测年份中均普遍存在且呈多向性，且未受主要表层流方向季节变化的显著影响。但约75%的采样幼体无法匹配至研究区域内的亲本，这表明有大量幼体来自研究区域外的种群。本研究数据验证了如下预测：幼体连通性的强度与时间稳定性随亚种群（subpopulations）间距的增大而显著降低，却随亚种群规模的扩大而提升。考虑到直接测定幼体交换需要投入大量工作，本研究发现的稳定格局表明，快照式亲子鉴定分析可提供有效的扩散量估算结果，为空间管理决策提供参考依据。