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

巴塔哥尼亚牙鱼(Dissostichus Eleinoides)和南极牙鱼(D.mawsoni)在北美市场上被广泛作为智利海鱼出售。根据遗传证据，牙鱼在经常与《南极海洋生物资源养护公约》(南极海洋生物资源保护公约)规定的岛屿群相对应的分区域内作为离散种群进行管理，并由邻近的国家当局管理。作为离散股票的管理，假设每个股票代表一个由自己的出生和死亡驱动的封闭人口，任何流浪者实际上都会消失。越来越多的证据表明，牙鱼可以移动相当远的距离；然而，移动速度被证明是很难检查的。鱼耳石中生长增量的基本结构反映了流经鳃的水的组成，从而反映了鱼所处的环境；生长增量还提供了直到捕获之前的生活史的时间顺序记录。耳石微量元素特征是鱼类过去位置的记录，主要研究人员使用基于激光的电感耦合等离子体质谱来检查巴塔哥尼亚牙鱼耳石中的元素特征，并确定管理区域之间的显著差异。使用这项技术对与已知捕获日期和地点相对应的耳石上的位置进行采样，将随着时间的推移和南大洋牙鱼集中的主要区域表征元素特征。利用最近拍摄的牙鱼，将生命历史中记录在耳石中的元素特征与地面实况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捞区域以外的地方。然后，基本数据将被用来估计目前种群中已迁徙的鱼类的比例，以及它们迁徙的生命阶段。通过收集每条鱼的耳石和遗传样本，耳石微量化学将被用来识别来源种群，并有效利用多基因座数据，不仅描述遗传上不同种群的分布，而且为估计混合比例提供基线数据。通过开发一套针对这两个物种的化学和遗传标记，将提供来源种群的全面特征和混合比例的准确估计。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，以澄清牙鱼运动的界限。该项目将提供对南极条约系统管理南大洋资源有价值的科学数据。这项建议还将涉及发展跨学科研究，包括少数族裔和代表性不足的学生、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.