Collaborative Research: A Comparison of the Mating System and Evolutionary Potential of Lemon Sharks, Negaprion Brevirostris (Poey), at Two Nursery Sites in the Western Atlantic

全球最紧迫的保护问题之一是海洋生态系统中大型掠食性鱼类，特别是鲨鱼的消失。尽管需要采取紧急行动，但对鲨鱼种群的空间尺度、进化动力学和繁殖生物学知之甚少，而这些是制定有效管理战略所必需的。这项研究将扩展对柠檬鲨繁殖生物学的长期分析，并首次针对任何大型海洋脊椎动物，使用定量遗传学方法研究关键适应性特征（生长，早期生存，条件因素）的进化动力学。研究人员将在先前研究的基础上，（1）直接确定雌性柠檬鲨是否会返回纳塔尔室分娩（纳塔尔philopatry），（2）在两个不同的托儿所，在当地和区域内检查柠檬鲨的交配系统（巴哈马的比米尼和佛罗里达的马克萨斯基），（3）使用数量遗传学来了解这两个地点适合度性状的遗传力和局部适应性，以及（4）记录我们在巴哈马的主要研究地点人为干扰的遗传影响。由于先前的支持，必要的微卫星标记已经完全开发出来，十年来从这两个种群中取样了2 000多条鲨鱼。“更广泛影响”教学和培训包括在比米尼生物野外站开设的三门大学课程，涉及正在进行的关于板鳃鱼类的研究。作为调查工作的一部分，来自世界各地的学生将在比米尼和马克萨斯基以及芝加哥的实验室接受培训。代表性不足的群体是通过一个特殊的私人资助的方案，使贫困高中学生，拉丁美洲人，加勒比和非洲裔美国人，每年到比米尼生物现场站的目标。除了在同行评审期刊上发表结果并在国际会议上发表外，我们的研究结果还将在即将到来的菲尔德博物馆展览“普利兹克实验室”中向公众展示。“这项研究的结果将用于建议佛罗里达群岛及其周围的柠檬鲨的适当管理计划，并提交给巴哈马政府，以协助指定比米尼泻湖为海洋保护区。

One of the most pressing global conservation concerns is the loss of large predatory fish, especially sharks, from marine ecosystems. Despite the need for urgent action, very little is known about the spatial scaling, evolutionary dynamics and breeding biology of shark populations, which is necessary to develop effective management strategies. This study will expand a long-term analysis of the breeding biology of the lemon shark, and for the first time for any large marine vertebrate, examine the evolutionary dynamics of critical fitness traits (growth, early survival, condition factor) using a quantitative genetics approach. The investigators will build on previous research to (1) directly determine whether female lemon sharks return to their natal nursery for parturition (natal philopatry), (2) examine the lemon shark's mating system both locally and regionally at two separate nurseries (Bimini, Bahamas and Marquesas Key, Florida), (3) use quantitative genetics to understand heritability and local adaptation of fitness traits at these two sites, and (4) document genetic impacts of an anthropogenic disturbance at our main study site in the Bahamas. As a result of prior support, the necessary microsatellite markers are fully developed and over 2000 sharks have been sampled over ten years from these two populations. The Broader Impacts Teaching and Training include three university courses given at the Bimini Biological Field Station and involving the ongoing research on elasmobranch fishes. As part of the investigators' work, students from around the world will be trained in both the field at Bimini and Marquesas Key as well as the laboratory in Chicago. Underrepresented Groups are targeted through a special privately funded program that brings for underprivileged high school students, Latino, Caribbean and African Americans, to the Bimini Biological Field Station annually. In addition to publishing results in peer-review journals and presenting at international meetings, our findings will be presented to the public in the upcoming Field Museum exhibit, "Pritzker Lab on the Floor." Results of this research will be used to suggest appropriate management schemes for lemon sharks in and around the Florida Keys and presented to the Bahamian government to assist in designating Bimini lagoon as a Marine Protected Area.