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

空间的需要？随着渔业科学家寻找传统海洋资源管理战略的替代办法，海洋种群的明确模型已变得显而易见。然而，由于缺乏对地理区域间的汇率的定量估计，开发海洋鱼类种群空间模型的努力受到了阻碍。分离的组（"连通性"）。这种知识的缺乏主要是由于进行标记的困难？在以产生大量小型中上层后代为特点的鱼种中进行的重新捕获研究，这些后代的初期死亡率很高。在这项研究中，Thorrold博士将继续开发和应用一种标记方法，该方法依赖于鱼类耳石（耳骨）地球化学的自然变化作为源位置的标记。最近的工作表明，它是可能的跟踪个别鱼从少年苗圃地区成人产卵的位置，使用这些地球化学签名作为自然标签的出生地点。耳石是一个理想的天然标签，因为：沉积时间的任何材料在耳石中可以确定参考定期增量的耳石。耳石是代谢惰性，和材料是不是重新？工作还是再？耳石的化学成分在一定程度上反映了鱼类生活的环境。 他们将开始一系列的实验室研究，以调查影响大西洋银鱼（Menidia menidia）幼虫耳石元素组成的因素。然后描述年轻人耳石的地球化学特征？的？的？一年（YOY）从沿着新英格兰海岸的10个河口的梅尼迪亚。将对耳石进行VC、8 "0"、Sr/16 Sr比值和多种微量元素（Mg/Ca、Mn/Ca、Sr/Ca和Ba/Ca）分析。这个过程将包括一个技术forquantifying 87 Sr/86 Sr同位素比值的耳石使用多？收集器电感耦合等离子体质谱由此产生的多元化学签名，在这些耳石将被用来开发最大似然估计分类成年Menidia返回河口沃茨产卵thefollowing一年。将对产卵期成虫的耳石进行切片，以显示在其出生河口的幼鱼居住期间放置的耳石部分。一个微型组合？钻孔和激光烧蚀ICP？MS将用于分析耳石这一部分的地球化学特征。从10个河口中的每一个收集的成鱼将被分配到出生河口的MLE算法的基础上，从地面？前一年在河口捕获的幼鱼的真实签名。这些数据将提供一个前所未有的空间尺度上的沿海鱼类物种通过出生归巢和流浪的连接性的定量估计。更一般地说，这项研究将提供一个研究框架，旨在通过利用海洋生物钙化结构中的自然特征，量化海洋生态系统的连通性。 拟议研究的教育部分将包括为麻省理工学院（WHO）生物海洋学联合项目开发渔业生态学和海洋学专题课程，指导WHO暑期学生奖学金的本科生，以及为马萨诸塞州高中教师开发和实施教师培训讲习班。他们将专注于一种常见的鱼类，这是学生最熟悉的沿海栖息地的重要组成部分。追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.