The hypothesis that salinity and temperature influence otoliths of Atherinella brasiliensis populations was investigated by comparing the morphologies and shapes of otoliths from two contrasting estuaries (positive and hypersaline). Overall, 462 otoliths were extracted from adult fish collected in both estuaries. For each otolith, the morphometric measurements (height, width, and length) and were recorded. We compared the morphology and shape of the otoliths from Brazilian silversides in different estuaries and estuarine zones (upper and lower) using multivariate analyses of variance and discriminant function analysis. Overall, two morphotype patterns were revealed through elliptic Fourier descriptors based on 30 harmonics. Significant differences in the morphologies and shapes of otoliths were found among and within estuaries, particularly in the population from the hypersaline estuary, which presented higher otolith areas and perimeter and height values in comparison with that from the positive estuary. The otolith morphometric variables were correctly classified into their original groups at more than 98.3 %, indicating a high rate of correct classification of individuals into their original populations. The weight of the otoliths was inversely related to the condition factor of fishes. The results highlight the significant correlations of environmental variables on otolith morphology, with both temperature and salinity being significant drivers of differences between populations.

盐度和温度对巴西Atherinella耳石影响的假说通过比较来自两个不同河口（阳性和高盐度）的耳石的形态和形状来研究种群。总的来说，从两个河口收集的成年鱼中提取了 462 颗耳石。对于每个耳石，记录形态测量值（高度、宽度和长度）并记录下来。我们使用多变量方差分析和判别函数分析比较了不同河口和河口区（上和下）的巴西银耳石耳石的形态和形状。总体而言，通过基于 30 个谐波的椭圆傅立叶描述符揭示了两种形态类型模式。在河口之间和河口内发现了耳石形态和形状的显着差异，特别是在高盐度河口的种群中，与阳性河口相比，它呈现出更高的耳石面积、周长和高度值。耳石形态测量变量正确归入原始群体的比例超过 98.3%，表明个体正确归入原始群体的比例很高。耳石的重量与鱼类的状况因素成反比。结果突出了环境变量与耳石形态的显着相关性，温度和盐度都是种群之间差异的重要驱动因素。表明将个体正确分类为原始种群的比率很高。耳石的重量与鱼类的体况因素呈负相关。结果突出了环境变量与耳石形态的显着相关性，温度和盐度都是种群之间差异的重要驱动因素。表明将个体正确分类为原始种群的比率很高。耳石的重量与鱼类的状况因素成反比。结果突出了环境变量与耳石形态的显着相关性，温度和盐度都是种群之间差异的重要驱动因素。