ABSTRACT: Populations of the Mediterranean fan mussel Pinna nobilis have progressively decreased over the last decades as a result of anthropogenic activities. The rate of decline has strongly increased since 2016, when a mass mortality event triggered by the parasite Haplosporidium pinnae occurred, and evidence exists that Mycobacterium species may also have played a major role in the event. Indeed, the epidemic has spread throughout the Mediterranean, although coastal lagoons seem to offer a degree of ‘resistance’ against the parasite. In the early 1980s, P. nobilis appeared in the Mar Menor lagoon and rapidly became an important component of the benthos. However, colonization of the lagoon by the fan mussel was cut short in 2016 when a massive mortality event occurred, possibly as a consequence of the environmental collapse that occurred in the lagoon, parallel to the mortality that the species suffered in the Mediterranean that same year. In this study, we estimated the spatial distribution of P. nobilis in the Mar Menor for 3 periods: 2003-2004, 2013 and 2016. The first 2 periods use published data, and the last period uses data collected in a new campaign. The probability of occurrence for the 3 periods was estimated using random forest and random forest regression-kriging models. The main environmental variables that determined the dispersion and colonization of the bivalve in the lagoon before 2016 are also identified.

中文翻译：

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Mar Menor沿海泻湖中的Pinna nobilis：殖民和不确定性的故事

摘要：由于人类活动，地中海扇贝贻贝（Pinna nobilis）种群在过去几十年中逐渐减少。自2016年以来，下降速度急剧增加，当时发生了由寄生虫羽扇形单胞菌引发的大规模死亡事件，并且有证据表明分枝杆菌物种也可能在该事件中起了主要作用。的确，尽管沿海泻湖似乎对这种寄生虫具有一定程度的“抵抗力”，但这种流行病已遍及整个地中海。在1980年代初期，诺比利斯体育出现在Mar Menor泻湖中，并迅速成为便当的重要组成部分。然而，在2016年发生大规模死亡事件时，扇贝贻贝对泻湖的定居时间缩短了，这可能是泻湖中发生的环境崩溃的结果，与同年该物种在地中海地区遭受的死亡相平行。在这项研究中，我们估计了假单胞菌的空间分布在Mar Menor中分为3个时期：2003-2004、2013和2016。前2个时期使用已发布的数据，最后一个时期使用在新广告系列中收集的数据。使用随机森林和随机森林回归-克里格模型估计3个时期的发生概率。还确定了决定2016年之前双壳类动物在泻湖中的分布和定殖的主要环境变量。