Retroactive Determination of Movement at Age in Relation to Water Mass in Patagonian Toothfish Through Laser-Based Elemental Analysis of Otoliths

9614756琼斯激光电感耦合等离子体质谱法是一种新技术，首次应用于南大洋，以检查巴塔哥尼亚齿鱼（Dissostichus eleginoides）的年龄运动。鱼类耳石中的生长增量的化学结构反映了穿过鳃的水的组成;增量也按时间顺序记录了捕获前个体鱼类的生活史，并用于老化。使用LA-ICPMS的元素分析允许在耳石中的一套元素的准确采样，给出了鱼所经历的水质量的变化的记录。这可以使用增量追溯地与年龄和真实的时间相关。 该项目是来自美国，英国，法国，智利和澳大利亚的科学家之间的国际合作。中心合作是在旧自治领大学和英国南极调查局的科学家之间进行的，将目前在该技术方面最广泛的经验与南极生命系统的经验结合在一起。来自法国、智利、澳大利亚和美国的科学家正在提供来自南大洋和南美洲南部的牙鱼耳石样本。 该项目由四个相互关联的模块，解决了总体问题：巴塔哥尼亚齿鱼在其生命史中的运动模式与水体在时间和空间上的变化有关？我们的目标是表明，LA-ICPMS技术可以区分巴塔哥尼亚齿鱼从不同的地理区域，开发一个有效的老化方法，并表征的变化的化学信号与年龄和年之间。其他目标是阐明差异产卵地点，并检查特定年龄的运动回顾性个别鱼类在南大洋，并在巴塔哥尼亚-斯科舍弧地区。NSF将只资助模块3（元素分析是否表明南大洋大西洋，伊尼亚和太平洋部门之间的巴塔哥尼亚洋枪鱼的运动？），单元1、2和4将由其他国家政府供资。 第一个模块包括一个初步的测试元素的变化耳石，使用LA-ICPMS。第二个是发展一个可靠的老化方法，充分验证标准的增长增量的解释，使用边际增量分析。第三个模块包括分析，与LAICPMS，一套元素，目前跨从麦夸里岛，Kerguelen群岛和南格鲁吉亚在南大洋的鱼的耳石部分。地区之间的耳石边缘的元素浓度的歧视将证实，该技术可以检测巴塔哥尼亚齿鱼的地理分离。按年级区分核浓度将表明产卵场是分开的。在耳石已知年龄的网站之间的比较将测试的变化，在元素配置文件与年龄对应的运动之间的水质量的鱼。不同年龄组鱼类的相同已知年龄地点之间的比较将测试不同年份之间的变化。第四个模块检查元素浓度在一个更精细的尺度上，比较连续一年的网站从智利北方和南部，福克兰群岛和南格鲁吉亚的耳石采样。 该项目的成果将直接惠及在南大洋内外工作的人口和生态系统生态学家、海洋学家和渔业管理人员。它们将表明在时间和空间上发生的移动，以及可能因海洋障碍而被隔离的种群。老化标准的验证将是一个重要的贡献，准确的巴塔哥尼亚齿鱼老化。更好地了解年龄和种群结构以及混合水平，对于使用渔业产量模型很重要;更好地了解环境过程所起的作用将有助于更好地预测补充和增长。 耳石的化学结构可用作追溯性环境记录，提供的数据可增强对年际变化在构建海洋生态系统中的作用的理解，并允许检测与气候引起的变化相关的趋势。

9614756 Jones Laser-based Inductively-Coupled Plasma Mass Spectrometry LA-ICPMS) is a new technique, which is being applied for the first time in the Southern Ocean, to examine movement-at-age in Patagonian Toothfish (Dissostichus eleginoides). The chemical structure of growth increments in the otoliths of fish reflects the composition of water passing across the gills; the increments also give a chronological record of the life history of individual fish before capture and are used for aging. Elemental analysis using LA-ICPMS allows accurate sampling of a suite of elements in the otoliths, giving a record of changes in the water mass experienced by the fish. This can be related retroactively to age and real time using the increments. The project is an international collaboration between scientists from the United States, United Kingdom, France, Chile and Australia. The central collaboration is between scientists at Old Dominion University and the British Antarctic Survey, bringing together the most extensive experience currently available of the technique, with that of Antarctic life systems. Scientists from France, Chile, Australia and the United States are providing samples of Toothfish otoliths from the Southern Ocean and southern South America. The project consists of four inter-linked modules, addressing the overall question: what are the patterns of movement of Patagonian Toothfish over its life history in relation to variability of water mass in time and space? The objectives are to show that the LA-ICPMS technique can discriminate between Patagonian Toothfish from different geographical regions, develop a validated aging method, and characterize the variability of the chemical signal with age and between years. Other objectives are to elucidate differential spawning sites, and examine age-specific movement retrospectively in individual fish within the Southern Ocean, and within the Patagonia-Scotia Arc region. NSF will fund only module 3 (Does eleme ntal analysis indicate movement of Patagonian toothfish between the Atlantic, Inian, and Pacific sectors of the Southern Ocean?), while modules 1, 2, and 4 will be funded by other governments. The first module consists of a preliminary test for elemental variability in otoliths, using LA-ICPMS. The second is the development of a reliable aging method with fully validated criteria for interpretation of growth increments, using marginal increment analysis. The third module consists of analysing, with LAICPMS, a suite of elements present across otolith sections of fish taken from Macquarie Island, the Kerguelen Islands and South Georgia in the Southern Ocean. Discrimination of element concentrations at the otolith edge between regions will confirm that the technique can detect geographic separation in Patagonian Toothfish. Discrimination by year class of concentrations at the nucleus will indicate that spawning sites are separate. Comparison between known-age sites in the otoliths will test for changes in the elemental profile with age corresponding to movement of fish between water masses. Comparison between the same known-age sites of fish from different age classes will test for variability between years. The fourth module examines elemental concentrations on a finer scale, comparing consecutive year sites across otoliths sampled from northern and southern Chile, the Falkland Islands and South Georgia. The results of the project will be of direct benefit to population and ecosystem ecologists, oceanographers, and fisheries managers working in the Southern Ocean and outside. They will indicate where movement occurs in time and space, and where populations are isolated potentially by oceanographic barriers. The validation of aging criteria will be a major contribution to accurate aging of Patagonian Toothfish. Better knowledge of age and stock structure, and mixing levels, is important for the use of fisheries yield models; better understanding of the role playe d by environmental processes will allow better prediction of recruitment and growth. The chemical structure of the otolith may be used as a retroactive environmental record, giving data that may enhance understanding of the role of inter-annual variability in structuring marine ecosystems, and allow detection of trends associated with climate-induced change.