Climate‐Driven Shifts in Green Turtle ( Chelonia mydas ) Hatchling Outcomes at Sabah Turtle Islands Park, Malaysia

Effective hatchery management is critical for sea turtle conservation, especially as environmental conditions influence incubation outcomes. Artificial shading is widely used to regulate nest temperatures, yet its effects on hatchling development and potential responses under future warming remain incompletely understood. This study examined incubation duration, hatching success and hatchling morphology from 113 green turtle ( Chelonia mydas ) nests monitored at Sabah Turtle Islands Park, Malaysia, between August 2023 and January 2024. Hatchling sex ratios were estimated using sand temperature data recorded by data loggers between 2019 and 2023. Future changes in incubation conditions and associated biological responses were explored using climate projections (SSP2‐4.5 and SSP5‐8.5) for 2050 and 2100. Shaded nests exhibited longer incubation durations, but the effects on reproductive outcomes varied seasonally, with shaded nests showing lower hatching success during the wet season (22.7% reduction). Hatchlings were relatively heavier during the dry season despite shorter incubation durations, suggesting additional environmental or maternal influences. Shading reduced sand temperatures by an average of 2.1°C ± 1.5°C compared with unshaded areas and produced more balanced sex ratios (40%–60% females), whereas unshaded nests were estimated to produce 60%–85% females. Under projected warming scenarios, sand temperatures increased substantially and exceeded thresholds associated with reduced hatching success, reaching 33.0°C under SSP2‐4.5 and surpassing 35.0°C year‐round under SSP5‐8.5. Overall, these findings suggest that shading can moderate incubation temperatures and influence hatchlings outcomes under current conditions. However, projected warming may exceed the buffering capacity of this intervention, highlighting the need to evaluate additional hatchery management strategies under future climatic change.