The occurrence of the jellyfish Aequorea cf. forskalea in the Adriatic Sea

Jellyfish are becoming an increasingly important component of studies the global marine environment, as their frequent mass phenomena affect ecosystem performance and have economic health consequences. Recent research has focused primarily on occurrences scyphozoans ctenophores, while less attention been paid to hydromedusae blooms, which can also significant impacts with Like many members Scyphozoa Ctenophora, Aequorea species be numerous form blooms. Based surveys from 2000 2020 information provided by professionals, we examine (multiannual) variability, seasonality, spatial distribution patterns poorly studied temperate cf. forskalea (Hydrozoa: Leptothecata). We hypothesized that this macrogelatinous jellyfish a bipartite life cycle (benthic polyps planktonic medusae) is sensitive seasonal long-term temperature fluctuations, particularly because shown play critical role in mediating transitions cnidarians. The cold-water affinity A. was confirmed negative correlation most occurrence during winter-spring period. For northern Adriatic (Gulf Trieste), sea data semi-quantitative plankton available for first decade 20th century, allowing comparison historical (1900-1911) our current set. Compared records, differs significantly. With warming Sea since beginning phenology changed, probably related delayed production medusae hydroids autumn, absence season winter.