Data from: Seascape genomics reveals fine-scale patterns of dispersal for a reef fish along the ecologically divergent coast of Northwestern Australia

Understanding the drivers of dispersal among populations is a central topic in marine ecology and fundamental for spatially explicit management of marine resources. The extensive coast of Northwestern Australia provides an emerging frontier for implementing new genomic tools to identify patterns of dispersal across diverse and extreme environments. Here we focused on the stripey snapper (Lutjanus carponotatus), which is important to recreational, charter-based, and customary fishers throughout the Indo-West Pacific. We collected 1016 L. carponotatus samples at 51 locations in the coastal waters of Northwestern Australia ranging from the Northern Territory to Shark Bay and adopted a genotype-by-sequencing approach to test whether realized connectivity (via larval dispersal) was related to extreme gradients in coastal hydrodynamics. Hydrodynamic simulations using CONNIE and a more detailed treatment in the Kimberley Bioregion provided null models for comparison. Based on 4,402 polymorphic SNP loci shared across all individuals we demonstrated significant genetic sub-division between the Shark Bay Bioregion in the south and all locations within the five remaining, more northern bioregions. More importantly, we identified a zone of admixture spanning a distance of 180 km at the border of the Kimberley and Canning bioregions, including the Buccaneer Archipelago and adjacent waters, which collectively experiences the largest tropical tidal range and some of the fastest tidal currents in the world. Further testing of the generality of this admixture zone in other shallow water marine species across broader geographic ranges will be critical for our understanding of the population dynamics of marine taxa in our tropical oceans.

解析种群间扩散的驱动机制，是海洋生态学研究的核心议题，同时也是海洋资源空间精准管理的重要基础。澳大利亚西北海岸广袤辽阔，为借助新型基因组学工具解析多样极端环境下的种群扩散模式提供了新兴研究前沿阵地。本研究以条纹笛鲷（Lutjanus carponotatus）为研究对象，该物种在印度-西太平洋海域的休闲垂钓、包船捕捞及传统渔业中均具有重要地位。我们在澳大利亚西北海域从北领地至鲨鱼湾的51个采样点采集了1016份条纹笛鲷样本，采用基因型分型测序（genotype-by-sequencing）技术，检验种群实际连通性（通过幼体扩散实现）是否与近岸水动力的极端梯度存在关联。本研究利用CONNIE软件开展水动力模拟，并在金伯利生物区开展精细化分析，以此构建用于对照的零模型。基于所有个体共有的4402个多态性单核苷酸多态性（SNP）位点，我们发现南部的鲨鱼湾生物区与其余5个更北部的生物区内所有采样点之间存在显著遗传分化。更为关键的是，我们在金伯利生物区与坎宁生物区的交界地带（涵盖海盗群岛及其邻近海域）发现了一处跨度达180公里的遗传混合区，该区域兼具全球最大的热带潮差与部分全球最快的潮流流速。后续需在更广地理范围内的其他浅海海洋物种中验证该遗传混合区的普遍性，这对我们理解热带海洋中海洋类群的种群动态具有至关重要的意义。