The argentine croaker, Umbrina canosai has a continuous distribution between Rio de Janeiro (22°S) in Brazil and Rio Colorado (41°S) in Argentina, but it is mostly harvested off Rio Grande do Sul, in southern Brazil. Two stocks have been classically described with little connection between them: one migrating between Argentina, Uruguay and South of Brazil, and the other off Sao Paulo and Rio de Janeiro states, in Brazil (Zaneti Prado and Vazzoler 1976; Haimovici et al. 2006). This differentiation has recently received support from two studies, one based on parasites (Canel et al. 2019) and one based on growth and otolith shape (Kikuchi et al. 2021). This profile focuses on the stock in the south of the distribution area including the south of Brazil, Uruguay, and Northern Argentina (Central Southwest Atlantic). In Brazil, isolated assessments have been conducted, the last one in 2019 (Cardoso et al. 2019).