Wintering Fish Habitat of Atlantic Chub Mackerel ( Scomber colias ) Southern Stock in SW Atlantic Ocean

The Atlantic chub mackerel ( Scomber colias ) is an important pelagic resource in the Southwestern Atlantic Ocean (SWAO), supporting socially and economically significant fisheries in Argentina. Two underexploited stocks occur on either side of 39° S, yet their economic importance and contribution to local employment require continued monitoring and informed management. During the austral winter, when most catches occur, the southern stock aggregates in the El Rincón area (ER), forming large, dense schools with pronounced vertical structure. This study identified the wintering habitat of S. colias and characterised the environmental conditions associated with this critical life‐history stage. Acoustic data from acoustic‐oceanographic surveys and official fishing reports between 2010 and 2024 were analysed. The presence and abundance of S. colias were evaluated, and bottom temperature and salinity, water column stability and depth were used as fixed predictors in generalised linear models (GLMs). The results demonstrate that these four environmental factors were related to the winter distribution of S. colias , enabling the delineation of its winter habitat, corroborated by the performance of the commercial fleet fishing on the ER. Combining fishery‐independent and fishery‐dependent data, a wintering habitat is characterised, with schools consistently occupying a narrow corridor aligned with the 50 m depth, defined by vertically homogeneous and thermally stable waters, with a restricted SBT (9.09°C–10.86°C) and SBS ranges (33.51–34.22). Identifying the environmental drivers shaping winter habitat use provides valuable insights for designing improved monitoring strategies and implementing spatially informed management measures for this socio‐economically important species.