Geometric morphometrics analysis provides evidence from the adaptive character of fish to the aquatic environment resulting from an evolutionary process. Thus, phenotypic variations among individuals are primarily due to heritability of genetic factors modulated by the surrounding environment. Analysis of body morphometry can provide important information on fish population structure, an essential prerequisite for conservation requirements and sustainable fisheries management. The “bigtooth corvina”, Isopisthus parvipinnis, is an euryhaline sciaenid fish widely distributed in the shallow and warm waters from the western Atlantic Ocean. It is often caught as bycatch of shrimp fisheries in Brazil. Although there is some basic ecological information about the species, knowledge about the stock structure is, at present, very limited. This work aims to investigate if the different environments of the South-Southeastern Brazilian coastal waters (São Paulo, Paraná, and Santa Catarina states) could affect the body shape of I. parvipinnis, allowing to define different population units through phenotypic geometric morphometrics. Juvenile fish, ranging between 66 and 139 mm of total length, were captured from September 2018 to May 2019 by research vessels and artisanal fleets using an otter trawl. Fish were photographed with 13 anatomical landmarks, and truss network analyses were performed using tpsUtil and tpsDig softwares. Data were analyzed through uni and multivariate statistical tests. Results showed significant differences among locations for all morphometric distances individually. Moreover, reclassification matrix presented a relatively high overall rate (79%). The hereby data suggest that I. parvipinnis in the study area is not a single and homogeneous stock, supporting the existence of a metapopulation structure. However, it is highly recommended to use complementary information, namely other natural tags, to corroborate these findings.

几何形态计量学分析提供了鱼类从进化过程中适应水生环境的适应性证据。因此，个体之间的表型变异主要是由于周围环境调节的遗传因素的遗传力。人体形态分析可以提供有关鱼类种群结构的重要信息，这是养护要求和可持续渔业管理的必要前提。“大齿科维纳”，Isopisthus parvipinnis，是一种淡水色的鱼腥草鱼，广泛分布在西大西洋的浅水和温暖水域中。在巴西，通常将其作为虾类捕捞的副渔获物。尽管有一些有关该物种的基本生态信息，但有关种群结构的知识目前非常有限。这项工作旨在调查巴西东南部东南沿海水域（圣保罗，巴拉那州和圣卡塔琳娜州）的不同环境是否会影响帕尔宾尼斯的体型。，允许通过表型几何形态计量学定义不同的种群单位。2018年9月至2019年5月，研究船和手工船队使用水獭拖网捕获了总长在66至139毫米之间的幼鱼。用13个解剖标志对鱼进行拍照，并使用tpsUtil和tpsDig软件进行桁架网络分析。通过单变量和多元统计检验分析数据。结果表明，对于所有形态计量距离，位置之间存在显着差异。此外，重分类矩阵显示出较高的总体比率（79％）。特此数据表明I. parvipinnis研究区域中的种群不是单一且均质的种群，这支持了种群结构的存在。但是，强烈建议使用补充信息，即其他自然标签，以证实这些发现。