Marine Mammal and Turtle Division, Southwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, La Jolla, CA 92037, USA.
Marine Mammal and Turtle Division, Southwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, La Jolla, CA 92037, USA; The Joint Institute for Marine and Atmospheric Research, Protected Species Division, Pacific Islands Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Honolulu, HI 96818, USA.
Curr Biol. 2018 Jan 8;28(1):154-159.e4. doi: 10.1016/j.cub.2017.11.057.
Climate change affects species and ecosystems around the globe [1]. The impacts of rising temperature are particularly pertinent in species with temperature-dependent sex determination (TSD), where the sex of an individual is determined by incubation temperature during embryonic development [2]. In sea turtles, the proportion of female hatchlings increases with the incubation temperature. With average global temperature predicted to increase 2.6°C by 2100 [3], many sea turtle populations are in danger of high egg mortality and female-only offspring production. Unfortunately, determining the sex ratios of hatchlings at nesting beaches carries both logistical and ethical complications. However, sex ratio data obtained at foraging grounds provides information on the amalgamation of immature and adult turtles hatched from different nesting beaches over many years. Here, for the first time, we use genetic markers and a mixed-stock analysis (MSA), combined with sex determination through laparoscopy and endocrinology, to link male and female green turtles foraging in the Great Barrier Reef (GBR) to the nesting beach from which they hatched. Our results show a moderate female sex bias (65%-69% female) in turtles originating from the cooler southern GBR nesting beaches, while turtles originating from warmer northern GBR nesting beaches were extremely female-biased (99.1% of juvenile, 99.8% of subadult, and 86.8% of adult-sized turtles). Combining our results with temperature data show that the northern GBR green turtle rookeries have been producing primarily females for more than two decades and that the complete feminization of this population is possible in the near future.
气候变化影响着全球的物种和生态系统[1]。温度上升的影响在温度依赖型性别决定（TSD）的物种中尤为明显，这些物种的个体性别是由胚胎发育过程中的孵化温度决定的[2]。在海龟中，随着孵化温度的升高，雌性幼龟的比例增加。预计到 2100 年，全球平均气温将上升 2.6°C[3]，许多海龟种群面临着高卵死亡率和只产雌性后代的风险。不幸的是，在筑巢海滩确定幼龟的性别比例既存在后勤上的困难，也存在伦理上的复杂性。然而，在觅食地获得的性别比例数据提供了多年来从不同筑巢海滩孵化的未成年和成年海龟的混合信息。在这里，我们首次使用遗传标记和混合种群分析（MSA），结合腹腔镜检查和内分泌学确定性别，将在大堡礁（GBR）觅食的雄性和雌性绿海龟与它们孵化的筑巢海滩联系起来。我们的结果显示，来自较凉爽的南部 GBR 筑巢海滩的海龟存在中等程度的雌性性别偏倚（65%-69%为雌性），而来自较温暖的北部 GBR 筑巢海滩的海龟则存在极高的雌性性别偏倚（99.1%的幼龟、99.8%的亚成龟和 86.8%的成年龟）。将我们的结果与温度数据相结合表明，北部 GBR 绿海龟繁殖地已经连续二十多年主要产生雌性海龟，而且该种群完全雌性化在不久的将来是有可能的。
