Coastal habitat degradation and green sea turtle diets in Southeastern Brazil

► The feeding area showed low species richness and was classified as degraded. ► The green turtle population was high afflicted by fibropapillomatosis. ► The green turtle diet was composed primarily by a single species, Ulva spp. (83.6%). ► Low diversity of available food items likely contributed to low dietary diversity. ► The nutritional implications of this restricted diet are unclear.