1. In the context of the River Rhône restoration programme, the objective of this study was to assess the dispersal and population connectivity of the European chub, Squalius cephalus (Linnaeus, 1758) in a section of the natural, free-flowing part of the lower River Rhône.
2. The elemental water signatures for Sr:Ca and Ba:Ca were measured at seven stations within the river section, including its tributaries and backwaters, to determine whether they could be differentiated by microchemistry. From August to October the signatures differed among three sectors of the study reach: the Rhône; the Ardèche; and the backwaters.
3. The elemental signatures of the otoliths of 178 young-of-the-year (YOY) chub from the stations were measured to assess spawning areas and identify early migratory life histories. Analyses of otolith microchemistry identified the natal origin of 95% of the fish. Sr:Ca signatures of otoliths showed early downstream migration for 30.4% of the YOY chub; however, 70% of the fish recruited relatively close to their spawning origin suggesting a potential inshore retention of fish.
4. The results showed (i) a non-negligible contribution of the tributaries and backwaters in the recruitment of fish into the main channel; and (ii) the ability of chub to migrate over several kilometres during their first few months of life.
5. This study shows that the combination of water and otolith microchemistry analyses of fish growth increases the understanding of fish life history. Moreover, the study revealed that half of the YOY fish from this river section came from the tributaries and the other half came from reproduction in the River Rhône (despite its high anthropization).
6. These methods offer promising future applications of otolith microchemistry for river management in the context of ecological rehabilitation, especially to assess the effectiveness of measures applied in the restoration of floodplain connectivity for riverine fish population conservation.

中文翻译：

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Squalius cephalus 早期生活史中的产卵区和迁徙模式（Linnaeus，1758 年）：耳石微化学用于保护和可持续管理

1. 在罗纳河恢复计划的背景下，本研究的目的是评估欧洲鲢鱼Squalius cephalus（Linnaeus，1758 年）在下游自然、自由流动的部分的分布和种群连通性罗纳河。
2. Sr:Ca 和 Ba:Ca 的元素水特征是在河段内的七个站点（包括其支流和回水）测量的，以确定它们是否可以通过微化学进行区分。从 8 月到 10 月，研究范围内的三个部分的签名有所不同：罗纳河；阿尔代什省；和死水。
3. 测量了来自站点的 178 只年幼 (YOY) 鲢的耳石的元素特征，以评估产卵区并确定早期迁徙生活史。耳石微化学分析确定了 95% 的鱼的出生起源。耳石的 Sr:Ca 特征显示了 30.4% 的 YOY chub 的早期下游迁移；然而，70% 的鱼在相对靠近其产卵地的位置被招募，这表明鱼类可能在近海滞留。
4. 结果显示 (i) 支流和回水在将鱼类补充到主要渠道方面的贡献不可忽视；(ii) chub 在生命的最初几个月内迁移数公里的能力。
5. 这项研究表明，对鱼类生长的水和耳石微化学分析相结合，增加了对鱼类生活史的了解。此外，研究表明，这条河段的 YOY 鱼有一半来自支流，另一半来自罗纳河的繁殖（尽管其高度人类化）。
6. 这些方法为耳石微化学在生态恢复背景下的河流管理中的未来应用提供了有希望的应用，特别是评估用于恢复泛滥平原连通性以保护河流鱼类种群的措施的有效性。