Use of skeletochronological analysis to estimate the age of leatherback sea turtles Dermochelys coriacea in the western North Atlantic
Use of skeletochronological analysis to estimate the age of leatherback sea turtles Dermochelys coriacea in the western North Atlantic
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DOI：
10.3354/esr00202
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发表时间：
2009-01-01
影响因子：
3.1
通讯作者：
Hastings, Mervin
中科院分区：
文献类型：
--
作者：
Avens, Larisa;Taylor, J. Christopher;Hastings, Mervin
虽然增长率和年龄数据是必不可少的棱皮龟管理，这些人口参数的估计仍然是推测性的，由于这种濒危物种的神秘的生活史。对来自北大西洋西部的8只圈养棱皮龟和33只野生棱皮龟的巩膜小骨进行了骨骼年代学分析，以表征小骨及其生长标志。年龄准确估计已知年龄的海龟，和他们的生长标记属性被用来校准生长标记计数的听小骨从野生标本。由于生长标记压实和吸收，在听小骨切片尖端可见的标记数量始终显著大于沿侧缘沿着可见的标记数量，表明应在尖端进行生长标记计数，以免低估年龄。一个校正因子协议，纳入早期生长增量的轨迹被用来估计在那些表现出吸收的听小骨，然后添加到观察到的标记的数量，以获得每个海龟的年龄估计的缺失标记的数量。一个广义平滑样条模型，冯Bertalanffy生长曲线，和大小在年龄函数被用来获得在北大西洋西部的棱皮龟成熟年龄的估计。这些分析的结果表明，在成熟的棱皮龟在世界的这一地区的中位数年龄可能从24.5至29岁。这些年龄估计数比以往研究中提出的年龄估计数大得多，对人口管理和恢复具有重大意义。
Although growth rate and age data are essential for leatherback management, estimates of these demographic parameters remain speculative due to the cryptic life history of this endangered species. Skeletochronological analysis of scleral ossicles obtained from 8 captive, known-age and 33 wild leatherbacks originating from the western North Atlantic was conducted to characterize the ossicles and the growth marks within them. Ages were accurately estimated for the known-age turtles, and their growth mark attributes were used to calibrate growth mark counts for the ossicles from wild specimens. Due to growth mark compaction and resorption, the number of marks visible at ossicle section tips was consistently and significantly greater than the number visible along the lateral edges, demonstrating that growth mark counts should be performed at the tips so that age is not underestimated. A correction factor protocol that incorporated the trajectory of early growth increments was used to estimate the number of missing marks in those ossicles exhibiting resorption, which was then added to the number of observed marks to obtain an age estimate for each turtle. A generalized smoothing spline model, von Bertalanffy growth curve, and size-at-age function were used to obtain estimates of age at maturity for leatherbacks in the western North Atlantic. Results of these analyses suggest that median age at maturation for leatherbacks in this part of the world may range from 24.5 to 29 yr. These age estimates are much greater than those proposed in previous studies and have significant implications for population management and recovery.