Caretta Research Project, Savannah, Georgia, United States of America.
Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, Gainesville, Florida, United States of America.
PLoS One. 2020 Apr 13;15(4):e0231325. doi: 10.1371/journal.pone.0231325. eCollection 2020.
Population assessments conducted at reproductive sites of migratory species necessitate understanding the foraging-area origins of breeding individuals. Without this information, efforts to contextualize changes in breeding populations and develop effective management strategies are compromised. We used stable isotope analysis of tissue samples collected from loggerhead sea turtles (Caretta caretta) nesting at seven sites in the Northern Recovery Unit (NRU) of the eastern United States (North Carolina, South Carolina and Georgia) to assign females to three separate foraging areas in the Northwest Atlantic Ocean (NWA). We found that the majority of the females at NRU nesting sites (84.4%) use more northern foraging areas in the Mid-Atlantic Bight, while fewer females use more proximate foraging areas in the South Atlantic Bight (13.4%) and more southerly foraging areas in the Subtropical Northwest Atlantic (2.2%). We did not find significant latitudinal or temporal trends in the proportions of NRU females originating from different foraging areas. Combining these findings with previous data from stable isotope and satellite tracking studies across NWA nesting sites showed that variation in the proportion of adult loggerheads originating from different foraging areas is primarily related differences between recovery units: individuals in the NRU primarily use the Mid-Atlantic Bight foraging area, while individuals from the three Florida recovery units primarily use the Subtropical Northwest Atlantic and Eastern Gulf of Mexico foraging areas. Because each foraging area is associated with its own distinct ecological characteristics, environmental fluctuations and anthropogenic threats that affect the abundance and productivity of individuals at nesting sites, this information is critical for accurately evaluating population trends and developing effective region-specific management strategies.
对迁徙物种繁殖地进行的种群评估需要了解繁殖个体的觅食区来源。如果没有这些信息,就无法准确评估繁殖种群的变化,并制定有效的管理策略。我们使用稳定同位素分析技术,对在美国东部北恢复单元(NRU)的七个筑巢地点(北卡罗来纳州、南卡罗来纳州和佐治亚州)收集的红海龟(Caretta caretta)组织样本进行分析,将雌性个体分配到西北大西洋(NWA)的三个独立觅食区。结果发现,NRU 筑巢地点的大多数雌性个体(84.4%)使用中大西洋湾更靠北的觅食区,而较少的雌性个体使用南大西洋湾更接近的觅食区(13.4%)和亚热带西北大西洋更靠南的觅食区(2.2%)。我们没有发现 NRU 雌性个体来自不同觅食区的比例存在显著的纬度或时间趋势。将这些发现与来自 NWA 筑巢地点的稳定同位素和卫星跟踪研究的先前数据相结合表明,来自不同觅食区的成年红海龟比例的变化主要与恢复单元之间的差异有关:NRU 的个体主要使用中大西洋湾觅食区,而来自佛罗里达三个恢复单元的个体主要使用亚热带西北大西洋和东墨西哥湾觅食区。由于每个觅食区都与自己独特的生态特征、影响个体在筑巢地丰度和生产力的环境波动和人为威胁相关,因此这些信息对于准确评估种群趋势和制定有效的区域特定管理策略至关重要。