The potential use of Sr/Ca and Ba/Ca ratios in fish otolith, as a complement to ⁸⁷Sr/⁸⁶Sr to study movements of Prochilodus lineatus, was evaluated in the La Plata Basin (South America). Water ratios were obtained from samples collected during the high and low water seasons at 42 sites across the La Plata Basin. Elemental and isotopic ratios in water were measured by MC-ICP-MS, ICP-MS and ion chromatography, and obtained from available literature. Fish were caught from six different sites with different physiochemical features. Otolith core-to-edge Sr/Ca and Ba/Ca profiles were determined by LA-ICP-MS, while the otolith ⁸⁷Sr/⁸⁶Sr data set was taken from literature. The predictive classification by rivers according to water Sr/Ca, Ba/Ca and ⁸⁷Sr/⁸⁶Sr ratios (92.5%) was higher than that based solely on ⁸⁷Sr/⁸⁶Sr (58%), with classification that reached 100% for several rivers. Unlike Ba/Ca, a significant relationship (R² = 0.94, p < 0.05) was found between otolith edge and water Sr/Ca, suggesting that this could be an efficient movement indicator for P. lineatus. The Sr/Ca ratio complemented the information provided by Sr isotopes and it was particularly useful in the northwest basin, where the isotopes alone do not allow differentiating between large rivers.

在拉普拉塔盆地（南美）评估了鱼耳石中Sr / Ca和Ba / Ca比率作为对⁸⁷ Sr / ⁸⁶ Sr的补充以研究线虫Prochilodus lineatus运动的潜在用途。从在拉普拉塔盆地整个地区的42个站点的高水位季节和低水位季节收集的样本中获得水比。水中的元素和同位素比率通过MC-ICP-MS，ICP-MS和离子色谱法测量，并从现有文献中获得。鱼是从六个具有不同理化特征的不同地点捕获的。耳石核心到边缘的Sr / Ca和Ba / Ca轮廓通过LA-ICP-MS测定，而耳石⁸⁷ Sr / ⁸⁶Sr数据集来自文献。根据水Sr / Ca，Ba / Ca和⁸⁷ Sr / ⁸⁶ Sr比率对河流的预测分类（92.5％）高于仅基于⁸⁷ Sr / ⁸⁶ Sr的预测分类（58％），其中分类达到100％。几条河。与Ba / Ca不同， 在耳石边缘和水Sr / Ca之间发现了显着的关系（R ²  = 0.94，p <0.05），这表明这可能是线虫的有效运动指示剂。Sr / Ca比值补充了Sr同位素提供的信息，在西北盆地特别有用，那里的同位素本身不能区分大河流。