CAREER: Connectivity Among Marine Fish Populations: Emphasizing Ecological Links Between Estuaries and the Coastal Ocean through an Integrated Program of Interdisciplinary Res/Educ

对空间的需求？随着渔业科学家寻找替代传统海洋资源管理策略的方法，海洋种群的明确模型已经变得显而易见。然而，由于缺乏对地理上不同鱼类之间汇率的定量估计，开发海洋鱼类种群空间模型的努力受到了阻碍。分离的组（“连接性”）。这种知识的缺乏主要是由于难以进行标记？对以生产大量小型远洋后代为特征的物种进行重捕研究，这些后代的初始死亡率很高。在这项研究中，Thorrold博士将继续开发和应用一种标记方法，该方法依赖于鱼耳石（耳骨）地球化学的自然变化作为来源位置的标记。最近的研究表明，利用这些地球化学特征作为出生地点的自然标签，有可能跟踪从幼鱼苗圃到成年产卵地点的个体。耳石是一种理想的天然标签，因为：耳石中任何物质的沉积时间都可以通过参考耳石的周期性增量来确定。耳石在代谢上是惰性的，而且物质不是re？工作还是休息？沉积后被吸附。在某种程度上，耳石的化学成分反映了鱼所生活的环境。他们将从一系列的实验室研究开始，调查影响大西洋银鱼幼鱼（Menidia Menidia）耳石元素组成的因素。在此基础上，分析了塔里木盆地新生代耳石的地球化学特征。新英格兰沿岸10个河口的梅尼迪亚。将对耳石进行VC， 8 ' 0， Sr/16 Sr比率和一些微量元素（Mg/Ca, Mn/Ca， Sr/Ca和Ba/Ca）的分析。这一过程将包括开发一种技术，用于量化耳石中的87 Sr/ 86 Sr同位素比率。收集器电感耦合等离子体质谱。这些耳石中产生的多元化学特征将用于开发最大似然估计值，以分类成年Menidia在第二年返回河口水域产卵。产卵的成年鱼的耳石将被切片，以显示幼鱼在其出生河口居住期间铺设的耳石部分。结合微？钻孔和激光烧蚀icp ？质谱将用于分析这部分耳石的地球化学特征。根据从地面开发的MLE算法，从10个河口收集的成鱼将被分配到出生河口。前一年在河口捕获的幼鱼的真实签名。这些数据将在前所未有的空间尺度上对沿海鱼类物种通过出生归巢和流浪的连通性提供定量估计。更一般地说，该研究将提供一个研究框架，旨在通过使用海洋生物钙化结构中的自然特征来量化海洋生态系统中的连通性。拟议研究的教育部分将包括为麻省理工学院[世卫组织]生物海洋学联合项目开发渔业生态学和海洋学主题课程，为世卫组织夏季学生奖学金的本科生提供指导，以及为马萨诸塞州的高中教师开发和实施教师培训讲习班。他们将把重点放在一种常见的鱼类上，这是学生们最熟悉的沿海栖息地的重要组成部分。跟踪鱼类从当地学生的后门到其他河口和沿海栖息地的运动的能力将强调盐沼，河口和沿海海洋的相互联系。

The need for spatially?explicit models of marine populations has become obvious as fisheries scientists search for alternatives to traditional management strategies for marine resources. Efforts to develop spatial models for marine fish populations have been handicapped, however, by the absence of quantitative estimates of exchange rates among geographically?separated groups ("connectivity"). This lack of knowledge is primarily due to the difficulty of conducting mark?recapture studies in species that are characterized by the production of large numbers of small pelagic offspring that suffer high initial mortality rates. In this study, Dr. Thorrold will continue development and application of a marking approach that relies upon natural variations in the geochemistry of fish otoliths (ear bones) as a marker of source location. Recent work suggests that it is possible to track individual fish from juvenile nursery areas to adult spawning locations using these geochemical signatures as a natural tag of natal location. The otolith is an ideal natural tag because:Deposition time of any material in the otolith can be determined by reference to periodic increments in the otolith.Otoliths are metabolically inert, and material is not re?worked or re?sorbed after deposition.The chemical composition of the otolith reflects, to some degree, the environment in which the fish has lived. They will begin with a series of laboratory studies to investigate factors influencing the elementalcomposition of otoliths in larval Atlantic silversides (Menidia menidia). Then characterizegeochernical signatures in otoliths of young?of?the?year (YOY) Menidia from 10 estuaries along the coastof New England. Otoliths will be assayed for VC, 8"0, "Sr/16 Sr ratios, and a number of trace elements(Mg/Ca, Mn/Ca, Sr/Ca and Ba/Ca). This process will include the development of a technique forquantifying 87 Sr/ 86 Sr isotope ratios in otoliths using multi?collector inductively coupled plasma massspectrometry. The resulting multivariate chemical signatures in these otoliths will be used to developmaximum likelihood estimators to classify adult Menidia returning to estuarine waters to spawn thefollowing year. Otoliths ftom spawning adults will be sectioned to reveal the section of the otolith laiddown during juvenile residency in their natal estuary. A combination of micro?drilling and laser ablationICP?MS will be used to assay geochemical signatures in this portion of the otolith. Adult fish collectedfrom each of the 10 estuaries will be assigned to natal estuary based on the MLE algorithm developedfrom ground?truthed signatures of juveniles captured in the estuaries the previous year. These data willprovide quantitative estimates of connectivity through natal homing and straying in a coastal fish specieson an unprecedented spatial scale. More generally, the study will provide a framework for research aimedat quantifying connectivity in marine ecosystems through the use of natural signatures in calcifiedstructures of marine organisms. The educational component of the proposed research will include thedevelopment of topics courses in fisheries ecology and oceanography for the MIT[WHOl joint program inbiological oceanography, the mentoring of undergraduates on summer student fellowships at WHOI, andthe development and implementation of teacher training workshops for high school teachers inMassachusetts. They will focus on a common fish species that is a critical component of coastal habitatswith which students are most familiar. The ability to track the movements of fish from the backdoors oflocal students to other estuarine and coastal habitats will stress the interconnectedness of salt marshes,estuaries and the coastal ocean.