Status, trends and conservation of global sea turtle populations

Sea turtles experienced myriad human impacts during the twentieth century that caused extreme mortality across all seven species. Extensive conservation efforts have been undertaken to protect sea turtles and reverse the major declines seen in many of their populations. In this Review we assess the status and trends of global sea turtle populations and identify conservation interventions that have been linked to population recoveries. Some threats, such as the direct harvest of turtles, have abated, but threats posed by climate change and loss of nesting habitat continue to escalate. Both the International Union for the Conservation of Nature (IUCN) Red List assessments and an analysis of sea turtle abundance time series have revealed that, in general, sea turtle populations are rebounding worldwide, with nest numbers increasing at many nesting sites. However, certain populations are still declining dramatically, such as leatherback turtle populations in the Pacific Ocean and Caribbean Sea. Key unresolved questions include whether sea turtles can adapt to climate change, the magnitude of climate warming’s impact on adult sex ratios, and the effect of growing threats such as increasing plastic pollution. Despite some conservation successes, cautious optimism is advised when considering the future of sea turtles in a rapidly changing world. This Review takes stock of global sea turtle populations, summarizing the dominant threats and most effective conservation interventions.