School of BioSciences, University of Melbourne, Parkville, Victoria 3010, Australia.
School of Life and Environmental Sciences, Centre for Integrative Ecology, Deakin University, Geelong, Victoria 3220, Australia.
Proc Biol Sci. 2019 Aug 28;286(1909):20191104. doi: 10.1098/rspb.2019.1104.
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, Trachinops caudimaculatus. 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 T. caudimaculatus 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.
幼虫扩散是决定底栖海洋生态系统种群连通性、复合种群动态和群落结构的关键过程，但扩散的生物物理复杂性尚未得到很好的理解。在这项研究中，我们使用一种温带珊瑚鱼物种 Trachinops caudimaculatus 研究了扩散者表型和水动力对幼虫扩散途径的相互作用。我们通过以下方式评估了幼虫特征对深度分布和扩散结果的影响：（i）使用 24 小时深度分层的浮游幼体采样，（ii）通过从个体幼虫的矢状耳石中提取的幼虫生长历史来量化个体表型，以及（iii）基于幼虫表型的经验分布和先进的生物物理海洋模型来模拟潜在的扩散结果。我们发现 T. caudimaculatus 幼虫在表型上呈垂直分层，高质量的表型存在于最底层和倒数第二层，而低质量的表型主要存在于表面。我们的模型表明，高质量和中等质量的幼虫经历了显著更高的本地保留（两倍以上）和自繁殖，并且与低质量幼虫相比，它们的迁移距离更短。由于只有当扩散者存活足够长的时间来繁殖时，种群才会连接起来，因此确定幼虫表型如何影响扩散结果对于提高我们对海洋种群连通性和持久性的理解将是重要的。
