Worrisome population indicators for leatherback sea turtles in Grenada

Grenada hosts a critical population of nesting Leatherbacks Turtles (Dermochelys coriacea), historically the third largest in the Caribbean. Ocean Spirits, a local non-profit NGO, completed their 22nd consecutive year of Leatherback nesting research in 2022 on Levera beach on the northeastern tip of the main island of Grenada. The International Union for the Conservation of Nature (IUCN) Red List status of Leatherback Turtles is ‘Vulnerable’; with fisheries by-catch posing the greatest global threat. In Grenada Leatherbacks face multiple threats including: illegal egg harvest, beach erosion and coastal development. Ocean Spirits data reveals declining nesting activities since 2018. In 2022 just 181 confirmed nests were laid by 63 individual females, the lowest number of nests since 2002. Between 2002 and 2022, the highest numbers of confirmed nests (n = 1143) and the highest number of individual nesting females (n = 198) occurred in 2014. Leatherback eggs require a consistent nest temperature of 25–35°C for successful embryonic development and hatching and sex determination is dependent on incubation temperature. Nest excavations at Levera Beach shown an average hatchling success of Leatherback turtles over the last decade to be 29.9%; this is well below the global average of 50–55%. Factors associated with the low hatchling success in Grenada are currently being investigated.