Abstract Spatiotemporal relationships between developmental stages (cydippid, transition and adult) of the comb jelly Mnemiopsis leidyi and environmental parameters were seasonally evaluated using the random forest (RF) model along the Iranian coasts of the Caspian Sea. The mean density of M. leidyi in spring, summer, autumn and winter were 8, 54, 130, and 15 ind m−3, respectively. The density of various stages, particularly cydippid, showed a decreasing trend with increase in depth. Cydippids had the highest abundance with a lower percentage in the deeper layers and colder seasons. Temperature was found to be the most influential parameter on the distribution of M. leidyi’s life stages, particularly cydippids, with a stronger effect in spring and summer. The highest densities for all life stages were observed above 20 °C with an explosive growth at above 25 °C for the cydippids. Moreover, cydippids were strongly influenced by all the three stages of the copepod Acartia tonsa (nauplius, copepodite and adult), especially its later developmental stages. Due to the presence of M. leidyi, the maximum zooplankton abundance has shifted to cold seasons. There was also a relationship between M. leidyi with barnacle larvae and rotifers in the cold seasons. The interrelationships among the life stages of M. leidyi, particularly between the transition and cydippid, was a major factor in its population dynamics. The relationship curves between these environmental parameters and the life stages of M. leidyi were nonlinear and mostly sigmoidal (not absolutely linear). The magnitude of parameter importance and relationships curves varied with season and life stage.

中文翻译：

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南里海侵入性栉水母生命阶段与环境参数之间的时空关系

摘要 使用随机森林 (RF) 模型沿里海伊朗海岸对栉水母 Mnemiopsis leidyi 的发育阶段（cydippid、过渡和成虫）与环境参数之间的时空关系进行季节性评估。春季、夏季、秋季和冬季的平均密度分别为 8、54、130 和 15 ind m−3。各阶段的密度，尤其是cydippid，随着深度的增加呈下降趋势。Cydippids 的丰度最高，在较深的层和较冷的季节中百分比较低。研究发现，温度是影响雷帝属植物生命阶段分布的最重要参数，尤其是在春夏两季影响较大。在 20°C 以上观察到所有生命阶段的最高密度，cydippids 在 25°C 以上出现爆炸性增长。此外，cydippids 受到桡足动物 Acariatonsa 的所有三个阶段（无节幼体、桡足类和成体）的强烈影响，尤其是其后期发育阶段。由于 M. leidyi 的存在，最大浮游动物丰度已转移到寒冷季节。在寒冷季节，M. leidyi 与藤壶幼虫和轮虫也有关系。M. leidyi 生命阶段之间的相互关系，特别是过渡期和 cydippid 之间的相互关系，是其种群动态的主要因素。这些环境参数与M. leidyi 生命阶段之间的关系曲线是非线性的，并且大部分是S形的（不是绝对线性的）。