Assessment of asynchronous emergence in Caretta caretta nests through a novel index for conservation applications

Abstract Hatchling emergence from the nest can occur both synchronously and asynchronously; Asynchronous patterns are increasingly reported in various sea turtle species, including Caretta caretta . A protracted emergence period can jeopardize hatching success, particularly if a limited number of hatchlings emerge during the initial emergence or on the first night. Rookeries with high hatching success may have been favored over time, as synchronous mass emergence increases hatchling survival rates during their early life stage. This study aims to assess the asynchrony of emergences in seven loggerhead sea turtle ( C. caretta ) nests on the Lazio coast of central Italy in 2021, focusing on its impact on hatching success. It introduces an asynchrony index to evaluate emergence success by integrating multiple parameters. The study confirms that hatchling behavior aligns with global observations, with hatchlings preferring to emerge at night. In the observed nests, emergences occur over at least three nights, resulting in multiple, staggered emergences.Global warming appears to promote the colonization of new beaches, which likely show varied patterns in the synchrony of hatchling emergence. Though preliminary, our index, if validated, could help assess a beach’s suitability for nesting alongside other factors. We recommend incorporating this index into future conservation efforts to enhance their effectiveness.