The seasonality of egg-laying in marine turtles is a well-known phenomenon that has been used to determine population trends based on an integration of the number of female emergences or nests during a season. However, in some cases, several peaks in female emergences are detected during single year. In this paper, we explore three such situations, two involving leatherback turtles laying eggs in French Guiana and in Northwest Coast of Papua, Indonesia and another involving green turtles in the Indian Ocean. In the three cases, we demonstrate the existence of a bimodal nesting season using a new statistical model. With this model, we show that estimates that fail to consider this bimodality into account can provide biased results both in terms of describing the phenology and quantifying the number of nests. The origin of these different groups of females is discussed based on the available information. This new model opens the door to a more rigorous analysis of egg-laying seasonality in marine turtles. Such rigor is essential in the current context of climate change, where shifts in seasonality can have a major influence on these species due to their temperature-sensitive sex determination.

中文翻译：

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海龟双峰筑巢季节之谜

海龟产卵的季节性是一个众所周知的现象，它已被用来根据一个季节内雌性出现或筑巢的数量来确定种群趋势。然而，在某些情况下，在一年内发现了几个雌性羽化高峰。在本文中，我们探讨了三种这样的情况，其中两种涉及法属圭亚那和印度尼西亚巴布亚西北海岸产卵的棱皮龟，另一种涉及印度洋的绿海龟。在这三个案例中，我们使用新的统计模型证明了双峰筑巢季节的存在。通过该模型，我们表明，未考虑这种双峰性的估计可能会在描述物候和量化巢数量方面提供有偏差的结果。根据现有信息讨论这些不同女性群体的起源。这个新模型为对海龟产卵季节性进行更严格的分析打开了大门。在当前气候变化的背景下，这种严格的要求至关重要，由于这些物种的性别决定对温度敏感，季节性变化可能对这些物种产生重大影响。