Inland fishing is an essential activity for the livelihood and food security the Colombian population. The knowledge and evaluation of exploited fish stocks is a priority to develop sustainable management and conservation strategies of the fisheries. To optimize the management processes of fishery resources and conservation of species, it is necessary to evaluate the population structure and identification of stocks. Geometric morphometrics analysis have shown useful in the evaluation of fish stocks. This study focuses on the species Plagioscion magdalenae, commonly called “Pacora”, corvinata, or river croaker, which belongs to the family Sciaenidae, a family characterized as an important fishery resource. With the aim of generating a baseline about the state of the P. magdalenae population structure, samples were collected along the marshy complex of the Dique channel, Colombia, between December 2020 and October 2021. In this study, the existence of morphometric variability between individuals of Plagioscion magdalenae was found across sampling sites, Ciénaga de Capote and Ciénaga del Jobo; shape differences between location suggest the action of environmental pressures and the existence of anthropogenic pressures, such as unsustainable artisanal fishing.