Green sea turtle conservation benefits from knowledge of population connectivity across different life stages. Green turtles are usually managed at the level of genetically discrete rookeries, yet individuals from different rookeries mix at foraging grounds. Rookeries may be impacted by processes at foraging grounds, hence rookery contributions to mixed foraging assemblages must be considered. Bimini, Bahamas, is an important foraging ground for juvenile green turtles, but rookery contributions to this assemblage have never been resolved. We generated mitochondrial DNA (mtDNA) sequences for 96 green turtles from Bimini and used Mixed Stock Analysis (MSA) to determine rookery contributions to this foraging assemblage using high-resolution (~817 base pair) and low-resolution (~490 base pair) rookery baseline data. The high-resolution data indicated that Quintana Roo, Mexico and Central Eastern Florida contributed most to Bimini. The low-resolution data indicated that Southwest Cuba and Central Eastern Florida contributed the most to Bimini. The results of the low-resolution MSA differ from a previous study conducted in Great Inagua, Bahamas which may reflect rookery size, rookery proximity to foraging grounds, the influence of currents, or a combination of these factors. While the presence of large credible intervals in our results does not permit explicit interpretation of individual MU contributions identified in MSAs, our results reveal substantial relative differences in rookery contributions to Bahamian foraging assemblages. Our study highlights the importance of regularly monitoring rookery contributions, resolving regional recruitment patterns to inform conservation, and the importance of using high resolution data in future MSA’s to improve rookery contribution accuracy.

Sea level rise has accelerated during recent decades, exceeding rates recorded during the previous two millennia1. Many coastal habitats and species around the globe are vanishing2. This situation is expected to worsen due to anthropogenically induced climate change. However, the magnitude and relevance of expected increase in sea level rise (SLR) for marine and terrestrial species reliant on coastal habitat for foraging, resting or breeding is unknown. We combined freely available digital elevation models for continental and remote island beaches across ocean basins with field data and sea level rise projections to explore the potential impact of SLR under various IPCC SLR scenarios on sea turtle nesting habitats at some of the largest rookeries worldwide. The study sites host five out of seven living species and all of them are categorized from vulnerable to critically endangered3 and essential due to sea turtles return to natal beaches to nest4. Our results confirm that the majority of sea turtle nesting habitat could vanish within the next few decades, leading to the depletion of many populations worldwide. Thus, even under moderate climate change scenarios, a large proportion of sea turtle nesting habitat will be flooded by 2050 and not survive to the end of the century. Overall, nesting populations with a low steep beaches slope and those species nesting at open beaches such as leatherback and loggerheads sea turtles might be the most affected under future SLR scenarios.