Green turtles (Chelonia mydas) are important herbivores that regulate productivity in warm temperate and tropical seagrass meadows globally. Green turtles in the Greater Caribbean region were severely depleted due to historical overexploitation. Some major nesting populations and foraging aggregations were harvested to extirpation and functional extinction. Following decades of protection under the Endangered Species Act and similar legislation elsewhere limiting or prohibiting harvest, most green turtle populations across the region appear to be on the road to recovery. However, as green turtle abundance has increased, the seagrass meadows on which they depend are facing declines due to anthropogenic threats. In turn, these seagrass declines threaten to erode vital ecosystem services in coastal regions. It’s unclear how increasing green turtle abundance and grazing pressure on degraded seagrass habitats will affect the long-term recovery of both the foundational seagrass communities and their consumers. Green turtles have complex life cycles, including an oceanic stage during which juveniles disperse from their natal beaches at a range of spatial scales. After a few years, these small juveniles ultimately recruit to coastal areas. These juveniles transition to new foraging habitats as they reach puberty. Many aspects of these ontogenetic shifts are poorly understood. Genetic tools have proven invaluable in linking these juveniles to their natal populations, but inferences are limited by the availability of baseline data and the resolution of the genetic markers employed. We are working with several partners across the Greater Caribbean region to apply mitogenomic approaches to: 1) Identify the number of discrete nesting populations and refine their boundaries. 2) Estimate population contributions to oceanic juvenile, neritic juvenile and subdault/adult foraging aggregations. 3) Resolve the spatial ecology of individuals representing each nesting population throughout their life cycle. 4) Characterize the magnitude and scale of male natal homing versus dispersal at courtship sites.