Collaborative Proposal: Population Spatial Structure and Stage-specific Connectivity of the Toothfishes Dissostichus eleginoides and D. mawsoni

巴塔哥尼亚齿鱼（Dissostichus eleginoides）和南极齿鱼（D. mawsoni）作为智利海鲈鱼在北美市场广泛销售。根据遗传证据，根据《南极海洋生物资源养护公约》（CCAMLR），齿鱼被作为离散种群管理在分区域内，通常对应于岛屿群，并由邻国国家当局管理。作为离散种群的管理假设每个种群代表一个封闭的种群，由其自身的出生和死亡驱动，任何游民都有效地丢失了。越来越多的证据表明，犬牙鱼可以移动相当远的距离；然而，运动速度已被证明是难以检验的。鱼耳石中生长增量的元素结构反映了通过鳃的水的组成，从而反映了鱼所处的环境；生长增量也提供了一个按时间顺序排列的生活史记录。耳石微量元素特征是过去鱼类位置的记录，主要研究人员使用基于激光的电感耦合等离子体质谱法来检查巴塔哥尼亚齿鱼（Dissostichus eleginoides）耳石中的元素特征，并确定管理区域之间的显着差异。利用这种技术对耳石上与已知捕获日期和地点相对应的位置进行采样，元素特征将随着时间的推移和南大洋齿鱼集中的主要区域而特征化。利用最近捕获的齿鱼，将耳石中记录的生活史元素特征与地面真实性分析中确定的相应空间特征进行比较。两个特征之间的差异将表明鱼来自捕获区域之外。然后，这些基本数据将被用来估计目前鱼群中迁移的鱼的比例，以及它们迁移的生命阶段。通过收集每条鱼的耳石和遗传样本，耳石微化学将用于确定来源种群，并有效利用多位点数据，不仅表征遗传上不同种群的分布，而且还为估计混合比例提供基线数据。通过为这两个物种开发一套化学和遗传标记，将提供源种群的综合特征和准确估计混合比例。作为这项研究的一部分，国际合作将包括在南极高地工作的科学家。这项工作将利用这些合作来进一步整合物理-生物成分，以澄清犬牙鱼运动的界限。该项目将为管理南大洋资源的《南极条约》系统提供有价值的科学数据。该提案还将涉及跨学科研究的发展，包括少数民族和代表性不足的本科生和研究生。

Patagonian toothfish (Dissostichus eleginoides) and Antarctic toothfish (D. mawsoni) are widely sold in the North American market as Chilean sea bass. On the basis of genetic evidence, toothfish are managed as discrete stocks within sub-areas frequently corresponding to island groups under the Convention for the Conservation of Antarctic Marine Living Resources (CCAMLR), and by neighboring national authorities. Management as discrete stocks assumes that each represents a closed population driven by its own births and deaths, and any vagrants are effectively lost. There is increasing evidence that toothfish can move considerable distances; however, rates of movement have proved difficult to examine. The elemental structure of growth increments in fish otoliths reflects the composition of water passing across the gills, and therefore the environment in which a fish is located; the growth increments also provide a chronological record of the life history up to capture. Otolith trace element signatures serve as a record of a fish's location in the past, and laser-based Inductively-Coupled Plasma Mass Spectrometry has been used by the principal investigators to examine elemental signatures in the otoliths of Patagonian toothfish (Dissostichus eleginoides), and to identify significant differences between management areas.Using this technique to sample the location on the otolith corresponding to the known date and site of capture, elemental signatures will be characterized over time and across the major areas of toothfish concentration in the Southern Ocean. Using toothfish taken recently, the elemental signatures recorded in the otolith during the life history will be compared with the corresponding spatial signatures determined in the ground-truthing analysis. Divergence between the two signatures will indicate that fish originated from outside the area of capture. The elemental data will then be used to estimate the proportion of fish currently in the population that have immigrated, and the life stage during which they migrated. By collecting otoliths and genetic samples from each fish, otolith microchemistry will be used to identify source populations and make effective use of multilocus data to not only characterize the distribution of genetically distinct stocks, but also to provide baseline data for estimating admixture proportions. By developing a set of chemical and genetic markers for both species, a comprehensive characterization of source populations and an accurate estimation of admixture proportions will be provided. As part of this research, international collaborations will include scientists working in the high Antarctic. This work will draw on these collaborations to further the integration of physical-biological components to clarify boundaries to the movement of toothfish. The project will provide scientific data will be of value in the Antarctic Treaty system on managing resources in the Southern Ocean. This proposal will also involve development of interdisciplinary studies that include minority and underrepresented, undergraduate, and graduate students.