Dissertation Research: Population Structure of the Green Sea Turtle Chelonia mydas

本研究的目的是确定濒临灭绝的绿海龟的种群结构。众所周知，绿海龟在浅水觅食的牧场和海浪筑巢的海滩之间广泛迁徙。标记研究表明，雌性海龟在连续的筑巢季节回到同一海滩筑巢。这种非凡的地点保真度让研究人员认为雌性海龟会回到它们出生的海滩上筑巢。如果绿海龟真的回到它们出生的海滩，那么每个鸟巢应该构成一个孤立的繁殖单位。在这项研究中，线粒体DNA(MtDNA)限制性分析将被用来(1)检验出生归巢假说，(2)确定绿海龟的种群结构。每个鸟巢从10-20个鸟巢中取出一个蛋，就可以得到样本。鉴于每个巢的蛋数量很多(约100枚)，而自然界中蛋和孵化的成活率极低，这种抽样策略对种群数量的影响可以忽略不计。初步结果与出生归巢假说一致。这项提案要求提供资金，以完成对绿海龟栖息地的全球调查，以便从基因上确定主要的筑巢组合。这些数据直接关系到绿海龟的繁殖行为和扩散问题。由于种群是物种管理的基本单位，结果对保护和管理机构立即有用。此外，有可能使用这项研究中产生的遗传标记来确定在加勒比海和其他地方的捕食场捕捞的绿海龟的来源。因此，这些调查结果可以大大改进国际管理政策必须基于的数据。

The goal of this research is to define population structure of the endangered green sea turtle, Chelonia mydas. Green sea turtles are known to migrate extensively between shallow feeding pastures and surf-built nesting beaches. Tagging studies have demonstrated that female turtles return to the same beach to nest in successive nesting seasons. This remarkable site fidelity led researchers to suggest that female turtles return to nest on their natal beach. If green sea turtles do return to their natal beach, then each rookery should constitute an isolated breeding unit. In this study mitochondrial DNA (mtDNA) restriction analysis will be used to (1) test the natal homing hypothesis, and (2) define population structure of the green sea turtle. Samples are obtained by removing one egg per nest from 10-20 nests per rookery. Given the large number of eggs (about 100) per nest and the extremely low survival rate of eggs and hatching in nature, this sampling strategy has a negligible impact on population size. Preliminary results are consistent with the natal homing hypothesis. This proposal requests funding to complete a global survey of green sea turtle rookeries in order to genetically define major nesting assemblages. These data bear directly on questions about the reproductive behavior and dispersal of green sea turtles. Since populations are the fundamental units of species management, results are of immediate use to conservation and management agencies. In addition, it may be possible to use genetic markers generated in this study to identify the origin of green sea turtles harvested on feeding grounds in the Caribbean and elsewhere. Thus, the findings can substantially improve the data upon which international management policy must be based.