Predicting core areas of flatback turtle hatchlings and potential exposure to threats

We used particle tracking forced by an ocean circulation model (ozROMS) to predict the passive dispersal of flatback turtle hatchlings (Natator depressus) from 12 nesting sites off the coast of Western Australia. We used the modelled outputs to calculate the distribution of these ‘virtual hatchlings’ and infer core areas of hatchlings use over three dispersal phases (1–4, 10–15 and 25–30 days). The core areas of use were located on the continental shelf during all dispersal phases, which provides support for their proposed neritic development. We then calculated the overlap between core areas and two anthropogenic threats to marine turtles which are in-water artificial infrastructure and light pollution. We found that hatchlings were mostly exposed to these threats during their early dispersal. As such, mitigations might be necessary for the conservation of this species and life-stage. The important areas that we define in this study should be validated by field surveys and can be used to guide future management and conservation of this age class and species in the absence of empirical data. Output files from particle tracking software (Ichthyop) for each nesting site each year and ESRI shapefiles of the calculated important areas for Day 1 to 4, Day 10 to 15, Day 25 to 30, which consists of the 25%, 50%, 75% and 95% cumulative frequency distribution. Also included are the particle release locations for each site.

本研究采用受海洋环流模型（ozROMS）驱动的粒子追踪方法，预测西澳大利亚近海12处筑巢点产出的平背龟（Natator depressus）幼龟的被动扩散过程。基于模型输出结果，计算这些"虚拟幼龟"的分布范围，并推断其在三个扩散阶段（1~4日、10~15日、25~30日）内的核心栖息区域。所有扩散阶段的核心栖息区域均位于大陆架海域，这为平背龟幼龟的浅海发育假说提供了支撑。随后，我们计算了核心栖息区域与海龟面临的两类人为威胁（水下人工设施与光污染）之间的重叠程度。研究发现，幼龟主要在扩散初期暴露于这些威胁之中。因此，为保护该物种及其该生命阶段，或需实施相关缓解措施。本研究划定的重要栖息区域需通过野外调查予以验证，在缺乏实测数据的情况下，可用于指导该年龄群体与该物种的后续管理与保护工作。本研究包含各年度各筑巢点的粒子追踪软件（Ichthyop）输出文件，以及针对1~4日龄、10~15日龄、25~30日龄阶段计算得到的重要栖息区域的ESRI形状文件，该文件包含25%、50%、75%与95%累积频率分布数据。此外还包含各筑巢点的粒子释放点位信息。