Discrete foraging landscapes support large scale migrations of a marine fish

Many marine animals migrate thousands of kilometers, yet the spatial extent of dietary resources acquired along these routes remains poorly understood. Identifying foraging areas across a species' annual cycle is critical for understanding habitat connectivity, aligning conservation with locations essential for sustaining populations, and predicting how environmental variability influences resources. We integrated continental-scale stable isotope assignment modeling (n = 417 individuals) with five years of electronic tagging (n = 85 individuals), using movement data to spatially constrain isotope-based foraging assignments, to identify foraging locations along migration routes of Atlantic tarpon (Megalops atlanticus). Distinct foraging regions emerged across the southeastern United States, including South Florida, the northern Gulf of Mexico, and the Mid-Atlantic Bight. Tissue-specific isotope incorporation rates indicated temporal variation in habitat use, with foraging activity often hundreds of kilometers from capture sites (mean distance to peak probability = 296 ± 188 km). These findings provide a framework for managing foraging habitats essential for highly migratory marine species.