DOI: 10.5061/dryad.w0vt4b8zh
title: Data from: Climate warming and sea turtle sex ratios across the globe

description: Climate warming and the feminisation of populations due to
 temperature-dependent sex determination may threaten sea turtles with
 extinction. To identify sites of heightened risk, we examined sex ratio
 data and patterns of climate change over multiple decades for 64 nesting
 sites spread across the globe. Over the last 62 years the mean change in
 air temperature was 0.85 °C per century (SD = 0.65 °C, range = -0.53 to
 +2.5 °C, n = 64 nesting sites). Temperatures increased at 40 of the 64
 study sites. Female-skewed hatchling or juvenile sex ratios occurred at 57
 of the 64 sites, with skews &gt; 90% female at 17 sites. We did not
 uncover a relationship between the extent of warming and sex ratio (r62 =
 -0.03, p = 0.802, n = 64 nesting sites). Hence, our results
 suggest that female-hatchling sex ratio skews are not simply a consequence
 of recent warming but have likely persisted at some sites for many
 decades. So other factors aside from recent warming must drive these
 variations in sex ratios across nesting sites, such as variations in
 nesting behaviour (e.g., nest depth), substrate (e.g., sand albedo),
 shading available and rainfall patterns. While overall across sites recent
 warming is not linked to hatchling sex ratio, at some sites there is both
 is a high female skew and high warming, such as Raine Island (Australia;
 99% female green turtles; 1.27 °C warming per century), nesting beaches in
 Cyprus (97.1% female green turtles; 1.68 °C warming per century), and in
 the Dutch Caribbean (St Eustatius; 91.5% female leatherback turtles; 1.15
 °C warming per century). These may be among the first sites where
 management intervention is needed to increase male
 production. Continued monitoring of sand temperatures and sex
 ratios are recommended to help identify when high incubation temperatures
 threaten population viability.
description: # Climate warming and sea turtle sex ratios across the globe
 [https://doi.org/10.5061/dryad.w0vt4b8zh](https://doi.org/10.5061/dryad.w0vt4b8zh) *Global Change Biology*: 10.111/gcb.17004 [https:](https://doi.org/10.111/gcb.17004)**[//doi.org/10.111/gcb.17004](https://doi.org/10.111/gcb.17004)** The underlying data that were generated and used to support the conclusions presented in our study are available in the following files: 1. Supplementary information: "Laloë et al. 2023 Glob. Change Biol. Suppl Info.pdf" 2. SI table 1: "SI table 1.xlsx" 3. SI table 2: "SI table 2.xlsx" Description of the data and variables included within the tables are as follow: **Table 1. Sex ratio and air temperature warming for 64 sea turtle nesting sites.** The **species** of sea turtles are: *Cc*, *Caretta caretta*; *Cm*, *Chelonia mydas*; *Dc*, *Dermochelys coriacea*; *Ei*, *Eretmochelys imbricata*; *Lk*, *Lepidochelys kempii*; *Lo*, *Lepidochelys olivacea*; and *Nd*, *Natator depressus*. Sex ratios were measured directly through the histological observation of the hatchling’s gonads (**HSR**) or were estimated from recorded sand temperatures using the established relationship between sex ratio and sand temperature (**TSR**). In one case (indicated below with an asterisk), sex ratios were measured through endocrinology. **Warming** is given as the air temperature difference between 1960-1969 and 2013-2022. Values in italic indicate that air temperatures between 1960-1969 were significantly different (p &lt; 0.05) to air temperatures between 2013-2022. We define three levels of **Conservation priority**: 0: both female sex ratio bias and warming are below average at these sites; 1: either female sex ratio bias or warming are above average at these sites; 2: both female sex ratio bias and warming are above average at these sites. Missing values are indicated by "NA". **Table 2. Sample sizes and study years of the sex ratio data examined in this study.** The **species** of sea turtles are: *Cc*, *Caretta caretta*; *Cm*, *Chelonia mydas*; *Dc*, *Dermochelys coriacea*; *Ei*, *Eretmochelys imbricata*; *Lk*, *Lepidochelys kempii*; *Lo*, *Lepidochelys olivacea*; and *Nd*, *Natator depressus*. In the column **Sample size,** the number of clutches or hatchlings used to estimate sex ratios is given when sex ratios were measured histologically, the number of loggers used in the study is given when sex ratios were estimated from temperature models, and the number of wild foraging turtles caught is given when sex ratios were measured through endocrinology. The years when the observations were made are given in the column **Year**. Missing values are indicated by "NA".