1. The Kemp’s ridley (Lepidochelys kempii) is the world’s most endangered sea turtle species. Predominately nesting at only one beach in Mexico, this species declined to an estimated 300 females in the mid-1980s. Conservation efforts in the United States and Mexico, including a head start programme in southern Texas in which hatchlings were reared in captivity for several months before being released into the wild, resulted in the recovery of this species.
2. Although genetic data have previously been used to assess the success of the head start programme and dispersal of individual adults, data on immature turtles sampled at foraging areas and adult females sampled at the main nesting beach in Mexico are lacking. Genetic characterization of immature individuals is important for understanding recruitment, survival, and population demography, while genetic data on individuals from Mexico are essential for understanding dispersal and overall genetic diversity in this species.
3. To address these gaps, mitochondrial DNA data were collected from 106 immature individuals sampled at four different foraging sites in the northern Gulf of Mexico and from 18 nesting females at the primary nesting beach in Mexico.
4. Two previously unknown mitochondrial DNA haplotypes were discovered among the immature individuals.
5. Except for these two new haplotypes, the genetic diversity of immature individuals in the northern Gulf of Mexico closely corresponds to that of adults sampled in Mexico, which suggests that much of the diversity within the nesting population can be found among immature animals dispersing to foraging grounds, including locations in the northern Gulf of Mexico.
6. Continued monitoring of the genetic variation of different life stages of this species across its distribution range will help assess the success of conservation programmes by ensuring the maintenance of genetic diversity and representation of this diversity across the species’ distribution range.

中文翻译：

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来自墨西哥湾北部的未成熟 Kemp'sridley (Lepidochelys kempii) 海龟的遗传多样性

1. 坎普氏龟（Lepidochelys kempii）是世界上最濒危的海龟物种。该物种主要在墨西哥的一个海滩筑巢，在 1980 年代中期减少到大约 300 只雌性。美国和墨西哥的保护工作，包括在德克萨斯州南部的先行计划，其中幼龟在被释放到野外之前被圈养数月，导致该物种的恢复。
2. 尽管以前曾使用遗传数据来评估先行计划的成功和个体成虫的扩散，但缺乏关于在觅食区采样的未成熟海龟和在墨西哥主要筑巢海滩采样的成年雌性海龟的数据。未成熟个体的遗传特征对于了解招募、生存和人口统计很重要，而墨西哥个体的遗传数据对于了解该物种的分散和整体遗传多样性至关重要。
3. 为了解决这些差距，从墨西哥湾北部四个不同觅食地点采样的 106 个未成熟个体和墨西哥主要筑巢海滩的 18 个筑巢雌性收集了线粒体 DNA 数据。
4. 在未成熟个体中发现了两种以前未知的线粒体 DNA 单倍型。
5. 除了这两种新的单倍型外，墨西哥湾北部未成熟个体的遗传多样性与在墨西哥采样的成年个体的遗传多样性密切对应，这表明筑巢种群内的大部分多样性可以在分散到觅食地的未成熟动物中找到，包括墨西哥湾北部的地点。
6. 持续监测该物种在其分布范围内不同生命阶段的遗传变异，将有助于评估保护计划的成功，确保在该物种分布范围内保持遗传多样性和这种多样性的代表性。