ABSTRACT: For species of conservation concern, somatic growth and age at maturation are key parameters in models used to evaluate population dynamics, as spatial and temporal variability in growth rates may be particularly important for predicting population recovery. Following an oceanic juvenile developmental stage, endangered Kemp’s ridley sea turtles Lepidochelys kempii occupy neritic habitats in 2 primary regions, the Gulf of Mexico (GoM) and along the US Atlantic coast. Results of prior studies suggest that somatic growth rates differ between these groups, which has the potential to influence maturation trajectories and relative reproductive contributions. To determine the nature and extent of potential regional differences, we conducted skeletal growth mark analysis (skeletochronology) with complementary annual bone growth increment-specific stable nitrogen isotope analysis that allowed delineation of oceanic-to-neritic habitat shifts for turtles stranded from 1993 to 2016. Results demonstrate that in the GoM, the oceanic-to-neritic habitat transition is associated with younger ages and faster somatic growth rates than in US Atlantic waters. Overall, US Atlantic somatic growth response was depressed relative to that in the GoM throughout all juvenile life stages, and this disparity persisted for more than 20 yr. This discrepancy translated into regional divergence in size-at-age relationships and maturation trajectories, with the prediction that US Atlantic Kemp’s ridleys would mature on average 2 to 3 yr later than their GoM counterparts. These analyses provide important baseline information on somatic growth rates and predicted age at maturation that can facilitate the evaluation of factors contributing to recent fluctuations in reproductive output for this endangered population.

中文翻译：

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肯普（Kemp）里德利（Rempley）海龟的生长轨迹和成熟年龄的差异

摘要：对于具有保护意义的物种，体细胞生长和成熟年龄是用于评估种群动态的模型中的关键参数，因为增长率的时空变化对于预测种群恢复可能特别重要。在海洋少年发展阶段之后，濒临肯普的里德利海龟Lepidochelys kempii在2个主要地区（墨西哥湾（GoM））和美国大西洋沿岸的沙生动物栖息地中。先前的研究结果表明，这些群体之间的体细胞生长速率不同，这可能会影响成熟轨迹和相对生殖贡献。为了确定潜在区域差异的性质和程度，我们进行了骨骼生长标记分析（骨骼年代学），并补充了年度骨骼生长增量特定的稳定氮同位素分析，该分析可以描绘1993年至2016年搁浅的海龟从海洋到有色动物栖息地的变化结果表明，在GoM中，与美国大西洋海域相比，从海洋到有神经栖的栖息地过渡与年龄较小和体细胞生长速率更快有关。总体，相对于GoM在所有少年生命阶段中的经历，美国大西洋的体细胞生长反应均受到抑制，并且这种差异持续了20多年。这种差异转化为年龄大小关系和成熟轨迹的区域差异，并预测美国大西洋肯普的ridleys平均比GoM同行成熟2至3年。这些分析提供了有关体细胞生长速率和成熟时预测年龄的重要基线信息，可以帮助评估造成这一濒临灭绝的人口近期生殖产出波动的因素。并预测，美国大西洋肯普郡的ridleys平均比GoM同行成熟2至3年。这些分析提供了有关体细胞生长速率和成熟时预测年龄的重要基线信息，可以帮助评估造成这一濒临灭绝的人口近期生殖产出波动的因素。并预测，美国大西洋肯普郡的ridleys平均比GoM同行成熟2至3年。这些分析提供了有关体细胞生长速率和成熟时预测年龄的重要基线信息，可以帮助评估造成这一濒临灭绝的人口近期生殖产出波动的因素。