Home Sweet Home? Habitat Occupancy of the Fuegian Sprat Sprattus fuegensis in a Sub‐Antarctic Marine Protected Area and Surrounding Environments

ABSTRACT The Fuegian sprat Sprattus fuegensis is an unexploited small pelagic fish that occupies a central position in sub‐Antarctic marine food webs of southern South America. Because of its role as a key forage species in wasp‐waist trophic systems, understanding the environmental drivers of its distribution and abundance is essential for ecosystem‐based management, conservation, and potential future fisheries. Here, we used acoustic surveys conducted between 2012 and 2019 to evaluate the spatial and temporal distribution of S. fuegensis schools and to identify the environmental characteristics associated with their habitat across years. Our results show that relative abundance, school morphology, and vertical distribution differed between the Namuncurá–Burdwood Bank Marine Protected Area and adjacent waters. Coastal waters of the Beagle Channel and the Atlantic Shelf of Tierra del Fuego showed the highest relative abundance, whereas the Burdwood Bank showed lower mean abundance but larger and deeper schools. Fuegian sprat abundance responded differently to the environmental variables analyzed, with chlorophyll a concentration and sea surface temperature emerging as the main drivers. Environmental clustering identified four habitat domains, indicating that S. fuegensis uses a spatially structured habitat mosaic in the southern southwestern Atlantic Ocean. Within this mosaic, the Burdwood Bank appears to function as a persistent oceanic habitat and potential regional connectivity hub. These findings provide an acoustic baseline for long‐term monitoring, climate‐sensitivity assessment, and future management of a key forage species in highly vulnerable sub‐Antarctic ecosystems.