Compound-Specific Nitrogen Isotope Analysis of Amino Acids in Eye Lenses as a New Tool to Reconstruct the Geographic and Trophic Histories of Fish
Compound-Specific Nitrogen Isotope Analysis of Amino Acids in Eye Lenses as a New Tool to Reconstruct the Geographic and Trophic Histories of Fish
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DOI：
10.3389/fmars.2021.796532
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发表时间：
2022-02-03
影响因子：
3.7
通讯作者：
Ohkouchi, Naohiko
中科院分区：
文献类型：
--
作者：
Harada, Yota;Ito, Shin-ichi;Ohkouchi, Naohiko
鱼类洄游在海洋养护和渔业管理中一直发挥着至关重要的作用。然而，随着海洋条件的变化，全球移徙模式也在发生变化。这影响到所需治理的空间规模，从而影响到我们的粮食供应。使用同位素的生物示踪剂方法的技术进步将使监测鱼类洄游的方法不同于传统的生物记录方法。鱼的眼睛晶状体是逐渐生长的，新陈代谢是惰性的。因此，眼睛晶状体的稳定同位素分析可以重建鱼类的地理和营养历史。然而，这是很难区分的两条信息：迁移和不断变化的营养关系与传统的散装稳定同位素的方法。在这项研究中，我们测量了单个氨基酸的氮同位素比值的鲢鱼（n = 3）从西北太平洋的眼睛晶状体，以测试是否可以区分这两条信息。从单眼透镜获得最多34个生长层。为了将在透镜组织中观察到的同位素趋势分配给特定的生命阶段或尺寸类别，我们建立了透镜尺寸和叉长（FL）之间的关系作为参考框架。重建的鲭鱼氮同位素分布显示，从幼鱼（FL∼30 mm）到成鱼（FL∼300 mm），营养位置增加了约1个单位。晶状体中苯丙氨酸（一种源氨基酸）的氮同位素比值变化范围为-3至5&PTSTHOUSND;。这种基线变异性可用于估计鱼类运动。本研究提出了一种新的工具，能够重建洄游鱼类的地理和营养历史的化合物特定的氮同位素分析的氨基酸在眼睛晶状体。
Fish migration has always played an essential role in marine conservation and fisheries management. However, migration patterns are changing globally alongside changing ocean conditions. This affects the spatial scale of required governance and, consequently, our food supply. Technological advances in the bio-tracer approach using isotopes would make it possible to monitor fish migration differently from the conventional bio-logging method. Eye lenses of fish are incrementally grown and metabolically inert. Therefore, stable isotope analysis of eye lenses can reconstruct the geographic and trophic histories of fish. However, it is difficult to distinguish between the two pieces of information: migration and changing trophic relationships with the conventional bulk stable isotope approach. In this study, we measured the nitrogen isotope ratios of individual amino acids in eye lenses of chub mackerel (n = 3) from the western North Pacific to test whether the two pieces of information could be distinguished. A maximum of 34 growth layers was obtained from a single eye lens. For assigning the isotopic trends observed in lens tissues to specific life stages or size classes, we established a relationship between lens size and fork length (FL) as a reference framework. The reconstructed nitrogen isotope chorology of chub mackerel showed an increase in trophic position of about 1 unit from juvenile (FL & SIM;30 mm) to adult stages (FL & SIM;300 mm). The variation in nitrogen isotope ratios of phenylalanine (a source amino acid) in the eye lenses was -3 to 5 & PTSTHOUSND;. This baseline variability could be used for estimating fish movements. This study proposed compound-specific nitrogen isotope analysis of amino acids in eye lenses as a new tool capable of reconstructing the geographic and trophic histories of migratory fish.