AUTHORS: Claire Sullivan, Wittenberg University; Dr.Matthew Godfrey, Duke University; Dr.Richard Phillips, Wittenberg University
ABSTRACT: Cape Lookout National Shoreline is a common area for marine turtles to nest in North Carolina. This study focuses on how Loggerhead (Caretta caretta) in situ nest incubation duration has changed over time from 2007 to 2023. Understanding the changes in incubation leads to the further question of estimating the sex ratio for marine sea turtles. The sex of marine turtles is determined by temperature; to estimate the sex ratio of sea turtles, both incubation duration and temperatures are applied. Regarding the temperature-dependent sex determination of Loggerheads, we analyze the changes in incubation duration on a seasonal and annual scale and how they correlate to annual and seasonal temperature changes. Nesting season begins in May and concludes in August. To account for seasonal temperature increases, data were divided into half-months. We hypothesize that as the nesting season progresses and the temperatures increase, the incubation duration of a clutch will decrease. July's first half month (1H) recorded the lowest averages in incubation duration (59.94± 5.641 days and 54.66± 3.478 days, respectively) for 2007-2009 as well as 2023. After assessing changes in half-months from 2007 to 2009 and 2023, an assessment of the annual changes from 2007 to 2009 and 2023 is made. Here, we show an average decrease in incubation duration from 2007-2009 to 2023 by 3.828 ± 2.39 days. Understanding the correlation between incubation duration and temperature and how they change both seasonally and annually may contribute to the understanding of the changing sex ratios for Loggerhead clutches that inhabit the Cape Lookout National Shoreline. Further questions on how sea turtles are affected by climate may involve changes in arrival time for nesting mothers.
