Jellyfish (JF) swarms impact human wellbeing and marine ecosystems. Their global proliferation is a matter of concern and scientific debate, and the multitude of factors affecting (and affected by) their density and distribution merits long-term monitoring of their populations. Here we present an eight-year time series for Rhopilema nomadica, the most prominent JF species swarming the Eastern Mediterranean Sea. Reports were submitted by the public and within it a group of trained participants via an internet website between June 2011 and June 2019. Data collected included species, size, location, ranked amount and stinging. Swarms of R. nomadica prevailed in July and ended in August but were also prominent in winter from January to March. Both observations deviate from past swarming patterns described in the late 1980s, when summer swarms persevered until October and winter swarms were not documented. Climate change (increasing water temperature) and the westwards up-current spread of R. nomadica are discussed as possible explanations for this phenological shift. We further demonstrate how data obtained by Citizen Science is used to develop a swarming indicator and monitor JF in time and space, and propose a forecast based on these observations.

中文翻译：

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地中海东部游走性高山红景天蜂群分布的物候变化

水母（JF）群影响人类福祉和海洋生态系统。它们的全球扩散是一个值得关注和科学辩论的问题，影响其密度和分布（并受其影响）的众多因素值得对其人口进行长期监测。在这里，我们提出了Rhopilema nomadica的八年时间序列，Rhopilema nomadica是遍布东地中海的最著名的JF物种。在2011年6月至2019年6月之间，公众及其内部的一群受过培训的参与者通过互联网网站提交了报告。收集的数据包括物种，大小，位置，排名数量和刺痛情况。群游牧七月盛行，八月结束，但在一月至三月的冬季也很盛行。两种观察结果都与1980年代后期描述的过去的蜂群模式有所不同，当时夏天的蜂群一直持续到10月，而冬天的蜂群没有记录在案。讨论了气候变化（水温升高）和游牧罗拉向西向上传播，以此解释了这种物候变化。我们进一步演示了如何使用Citizen Science获得的数据来开发蜂拥指标并在时间和空间上监视JF，并根据这些观察结果提出预测。