Supporting data file - larval density from Dispersal and population connectivity are phenotype dependent in a marine metapopulation

Larval dispersal is a key process determining population connectivity, metapopulation dynamics and community structure in benthic marine ecosystems, yet the biophysical complexity of dispersal is not well understood. In this study, we investigate the interaction between disperser phenotype and hydrodynamics on larval dispersal pathways, using a temperate reef fish species, <i>Trachinops caudimaculatus</i>. We assessed the influence of larval traits on depth distribution and dispersal outcomes by: (i) using 24-h depth-stratified ichthyoplankton sampling; (ii) quantifying individual phenotypes using larval growth histories extracted from the sagittal otoliths of individual larvae; and (iii) simulating potential dispersal outcomes based on the empirical distribution of larval phenotypes and an advanced biological-physical ocean model. We found <i>T. caudimaculatus</i> larvae were vertically stratified with respect to phenotype, with high-quality phenotypes found in the bottom two depth strata, and poor-quality phenotypes found primarily at the surface. Our model showed high- and average-quality larvae experienced significantly higher local retention (more than double) and self-recruitment, and travelled shorter distances relative to poor-quality larvae. As populations are only connected when dispersers survive long enough to reproduce, determining how larval phenotype influences dispersal outcomes will be important for improving our understanding of marine population connectivity and persistence.

幼体扩散（larval dispersal）是调控底栖海洋生态系统（benthic marine ecosystems）中种群连通性、集合种群动态与群落结构的核心过程，然而该过程的生物物理复杂性迄今尚未得到充分阐释。本研究以温带礁栖鱼类尾斑弱棘鯻（*Trachinops caudimaculatus*）为研究对象，探究扩散者表型与水动力过程对幼体扩散路径的交互作用。我们通过以下三种途径评估幼体性状对其垂直分布与扩散结局的影响：(i) 开展时长24小时的分层鱼类浮游生物（ichthyoplankton）采样调查；(ii) 提取单尾幼体的矢耳石（sagittal otoliths）生长历史，以此完成个体表型的定量表征；(iii) 结合幼体表型的实测分布数据与先进的生物物理海洋模型，模拟潜在的扩散结局。研究发现，尾斑弱棘鯻幼体的表型存在显著垂直分层现象：高质量表型幼体主要分布于下层两个水层，而低质量表型幼体则集中分布于表层水体。模型模拟结果显示，高质量与中等质量的幼体其本地滞留率（local retention）显著更高（可达低质量幼体的两倍以上），且自我补充率（self-recruitment）更高、扩散距离更短。种群间的连通性仅当扩散个体存活至具备繁殖能力时方可实现，因此阐明幼体表型对扩散结局的调控机制，对于深化我们对海洋种群连通性与种群存续的认知具有关键意义。