DISSERTATION RESEARCH: Investigating patterns and processes of evolution, ecology, and diversification in carangiform fishes

该项目研究了两种标志性海洋鱼类的遗传多样性，巨型鲹鱼和蓝鳍鲹鱼。这两个物种都是印度洋和太平洋珊瑚和岩石礁的顶级捕食者，在手工、商业和运动渔业中都很有价值。该研究将调查印度-太平洋地区遗传多样性与环境变量（例如海洋温度和洋流）之间的相关性，以确定可能导致不同地理位置这些鱼类基因组观察到差异的物理障碍。该项目的重点是西印度洋，该地区缺乏足够的海洋保护措施，这在很大程度上是由于缺乏为政府制定管理决策提供信息所需的数据。考虑到缺乏这两个物种的数据，再加上它们在经济上的重要性，这个项目具有直接的社会意义。这些研究人员将与政府和非营利合作者共享数据，为研究生纳入强有力的科学培训内容，并与美国、南非和塞舌尔的公众成员进行接触。为了实现项目目标，研究人员将首先使用下一代测序技术进行海景遗传分析，特别是针对单核苷酸多态性（snp）的双消化限制位点相关DNA测序（RADseq），以检查C. ignobilis和C. melampygus个体内部和之间的精细遗传结构。将使用结合海洋数据和这些物种的生物属性的耦合生物-物理模型来分析海景属性。将建立模型，最大限度地利用与遗传数据互补的空间尺度上的海洋学信息。第二个部分包括系统地理学分析，重点是通过使用古气候数据来表征可能驱动进化并影响两个物种历史和现在数据分布的物理和生物力量，从而表征历史基因流动模式。该方法使用高分辨率古海洋学模型和基于现代gis的物种分布建模算法来生成每个物种的古分布适宜性值。这些古分布可以作为对SNP数据集进行测试的替代假设。综合起来，这些分析将提供对塑造这两个重要渔业物种的多样化和连通性的当代和历史进程的见解。

This project examines genetic diversity in two species of iconic marine fishes, the Giant Trevally and the Bluefin Trevally. Both species are top predators on coral and rocky reefs throughout the Indian and Pacific Oceans and are highly valued for artisanal, commercial, and sport fisheries. The research will investigate the correlation between genetic diversity and environmental variables (e.g., ocean temperature and currents) in the Indo-Pacific to identify physical barriers that might lead to observed differences in the genomes of these fishes in different geographic locations. The project focuses on the western Indian Ocean, a region lacking sufficient marine conservation measures in large part due to a scarcity of data necessary to inform governments making management decisions. Given the lack of data on these two species of Trevally, coupled with their economic importance, this project has direct societal implications. The researchers will share data with governmental and non-profit collaborators and incorporate strong scientific training components for graduate students, as well as engagement with members of the public in the USA, South Africa, and Seychelles. To accomplish the project objectives, the researchers will first conduct seascape genetic analyses using next generation sequencing techniques, specifically double digest restriction site associated DNA sequencing (RADseq) targeting single nucleotide polymorphisms (SNPs) to examine fine-scale genetic structure within and among C. ignobilis and C. melampygus individuals across their range. Seascape properties will be analyzed using coupled biological-physical models that integrate oceanographic data with biological attributes of these species. Models will be generated that maximize the availability of oceanographic information at a spatial scale complementary to the genetic data. The second component includes a phylogeographic analysis focused on characterizing patterns of historic gene flow by using paleoclimatic data to characterize physical and biological forces that may have driven evolution and influenced historical and present data distributions of the two species. This methodology uses high-resolution paleoceanographic models coupled with contemporary GIS-based species distribution modeling algorithms to generate paleodistribution suitability values for each species. These paleodistributions serve as alternate hypotheses to test against the SNP dataset. In combination, these analyses will provide insight on contemporary and historical processes shaping the diversification and connectivity of these two important fishery species.