Monitoring threatened species is essential for setting conservation priorities and measures to prevent species extinction. The endemic species is now classified on the IUCN Red List as a critically endangered species, with the only possibility to observe entire populations in very specific coastal areas, and a few resistant individuals in open waters. Thus, monitoring and management of these populations are crucial to avoid global species extinction. The present study aims to monitor Mar Menor's coastal lagoon population and to evaluate its possible resilience to recuperate from several environmental catastrophes and human mediated impacts that drastically decimated the population between 2016 and 2019. To do so, between 2019 and 2022, we assessed its population maintenance and its reproductive success. First, we monitored changes in overall densities and shell growth, and we installed between 23 and 45 larvae collectors to assess reproductive success. We observed stabilization of population densities and positive shell growth of individuals. However, no incorporation of recruits into this ageing population was observed. Our results highlighted the lack of species recovery and the first signs of probable local population extinction. Therefore, urgent management and conservation actions focused on restoring the ecosystem and protecting individuals are needed to avoid this population extinction and loss of one of the last reservoirs of this emblematic species.

中文翻译：

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老龄化人口没有新成员：极危物种羽翼的最后一个储存库之一出现可能种群灭绝的第一个迹象

监测受威胁物种对于制定保护优先事项和防止物种灭绝的措施至关重要。这种特有物种现已被世界自然保护联盟红色名录列为极度濒危物种，只有在非常特定的沿海地区才能观察到整个种群，并在开阔水域观察到一些有抵抗力的个体。因此，对这些种群的监测和管理对于避免全球物种灭绝至关重要。本研究旨在监测马尔梅诺沿海泻湖的种群，并评估其从 2016 年至 2019 年间导致人口大幅减少的几次环境灾难和人类影响中恢复的可能性。为此，我们在 2019 年至 2022 年间评估了其种群数量维持及其繁殖成功。首先，我们监测总体密度和壳生长的变化，并安装了 23 至 45 个幼虫收集器来评估繁殖成功率。我们观察到种群密度的稳定和个体贝壳的积极生长。然而，没有观察到新兵加入到这个老龄化人口中。我们的结果强调了物种恢复的缺乏以及当地种群可能灭绝的最初迹象。因此，需要采取以恢复生态系统和保护个体为重点的紧急管理和保护行动，以避免种群灭绝和这一标志性物种最后一个储存库之一的丧失。