Mesoscale Oceanographic Processes Drive the Seasonal Abundance of the Seabob Shrimp <i>Xiphopenaeus</i> spp. on the Eastern Brazilian Shelf

ABSTRACT The seabob shrimp ( Xiphopenaeus spp.) is a primary fishery resource in Brazil, with considerable economic and social importance along the coast. While environmental drivers of its life cycle are well‐documented for southeastern and southern populations, the factors modulating populations in the Eastern Brazilian Shelf remain poorly understood, affecting resource management directly. To assess the influence of mesoscale oceanographic processes on the abundance of the seabob shrimp within the Abrolhos Bank, a 19‐year time series of relative abundance, primary productivity, bottom water temperature, and river flow was analyzed using generalized additive models. Abundance peaks were identified in austral autumn and spring, revealing non‐linear, time‐dependent relationships between CPUE and environmental predictors. The seasonal interaction model indicated that the May abundance peak resulted from the combined effect of cooling and increased primary productivity. Abundance increased by up to 35% during these peaks, while river discharge exhibited a predominantly inverse relationship. Our findings indicate that eastern populations are modulated by Vitória Eddy and South Atlantic Central Water upwelling over the Abrolhos Bank. This regional differentiation reflects the ecological plasticity of Xiphopenaeus spp. and its adaptation to regional processes that enhance nutrient supply. These results support site‐specific management and conservation strategies across the Southwestern Atlantic.