Estimating population abundance is key for species of conservation concern. This is particularly challenging for marine animals, like sea turtles, with ocean-scale distribution and migratory nature. However, sea turtles lay clutches on land where they can be easily counted; thus, clutch number has always been the most common index of population abundance. A female typically lays >1 clutch per year and does not reproduce every year. Therefore, 2 conversion factors are needed to convert the number of egg clutches to the number of adult females: the number of clutches laid by a female in a nesting season and the fraction of adult females reproducing in a season, which is linked to the breeding periodicity. The effects of breeding periodicity, probability of detection and annual survival probability on the derived adult female abundance were investigated by simulating a virtual population of adult females over a 15 yr beach monitoring period. The results indicate that current methods may greatly overestimate the abundance of sea turtle populations, especially in situations with a low detection probability, including temporary emigration. The factors involved and ways to minimize biases and errors are discussed, including a method which is easy to implement using existing datasets. A careful reassessment of current estimates of sea turtle abundance derived from nest counts and capture-mark-recapture data would be appropriate, and the potential error associated with such estimates should be considered when they are used in conservation status assessments.

中文翻译：

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世界范围内的海龟种群从迁徙间隔被高估：偏差校正

估计种群丰度是保护关注物种的关键。这对具有海洋规模分布和迁徙性质的海洋动物（如海龟）尤其具有挑战性。然而，海龟在陆地上紧紧抓住它们，在那里它们很容易被数到。因此，离合器数量一直是最常见的人口丰度指标。雌性通常每年产下超过 1 个离合器并且不会每年繁殖。因此，将卵窝数量转换为成年雌性数量需要2个转换因子：一个雌性在一个筑巢季节产卵的数量和一个季节中成年雌性繁殖的比例，这与繁殖有关。周期性。繁殖周期的影响，通过在 15 年的海滩监测期内模拟成年女性的虚拟种群，研究了衍生的成年女性丰度的检测概率和年生存概率。结果表明，当前的方法可能大大高估了海龟种群的丰度，尤其是在检测概率较低的情况下，包括临时移民。讨论了所涉及的因素以及最小化偏差和错误的方法，包括使用现有数据集易于实施的方法。仔细重新评估根据巢穴计数和捕获标记重新捕获数据得出的当前海龟丰度估计值是合适的，并且在将它们用于保护状态评估时应考虑与这些估计值相关的潜在误差。