Anthropogenic climate change poses a significant threat to marine turtles due to temperature dependent sex determination. Rising nest temperatures are causing female bias hatchling production, with potential long-term consequences for genetic diversity, effective population size, and the availability of breeding males. However, the extent and timing of feminisation varies among turtle species and genetic stocks, highlighting the need for species and location-specific modelling, particularly in remote nesting areas where intervention thresholds remain poorly understood.
In this study, temperature data loggers were deployed at nest depth, and in shaded and unshaded sites, on Lihou Reef in the Coral Sea Marine Park to characterise contemporary nesting conditions. Historical air temperature records from the International Comprehensive Ocean-Atmosphere Data Set were used as a proxy to model past hatchling sex ratios, while future hatchling sex ratios were projected to the end of the century using Intergovernmental Panel for Climate Change scenarios calibrated with current nest temperature data.
These models provide the first assessment of the vulnerability of this ecologically important rookery to climate-driven feminisation and will help determine the level of risk to turtle hatchlings at Lihou Reef, as well as whether and when management interventions may be required.