As suspected at the turn of this century, jellyfish blooms are increasing in frequency. Between 2013 and 2020 the Mediterranean Science Commission monitored on a weekly basis the frequency of such outbreaks in coastal waters from Morocco to the Black Sea, revealing a relatively high frequency of these blooms nearly all year round, with peaks observed from March to July and often again in the autumn. The blooms are caused by different jellyfish species, depending on their localisation within the Basin: one observes a clear dominance of Pelagia noctiluca and Velella velella outbreaks in the western Mediterranean, of Rhizostoma pulmo and Rhopilema nomadica outbreaks in the eastern Mediterranean, and of Aurelia aurita and Mnemiopsis leidyi outbreaks in the Black Sea.
As suspected at the turn of this century jellyfish blooms are increasing in frequency Between 2013 and 2020 the Mediterranean Science Commission monitored on a weekly basis the frequency of such outbreaks in coastal waters from Morocco to the Black Sea revealing a relatively high frequency of these blooms nearly all year round with peaks observed from March to July and often again in the autumn The blooms are caused by different jellyfish species depending on their localisation within the Basin one observes a clear dominance of Pelagia noctiluca and Velella velella outbreaks in the western Mediterranean of Rhizostoma pulmo and Rhopilema nomadica outbreaks in the eastern Mediterranean and of Aurelia aurita and Mnemiopsis leidyi outbreaks in the Black Sea