Jellyfish diversity, trends and patterns in Southwestern Mediterranean Sea: a citizen science and field monitoring alliance

Abstract Jellyfish (Cnidaria and Ctenophora) are an essential component of marine ecosystems represent a potential effect, positive or negative, for several economic activities. blooms non-indigenous species (NIS) introduction can shift ecological community structure energy transfer. Despite their importance in ecosystem function services, knowledge jellyfish fauna diversity phenology largely lacking the southern Mediterranean Sea. Here, we present overview current state biodiversity Tunisia. Based on comprehensive literature survey, historical records unpublished data, 66 species, including 11 have been recorded Tunisia between 1994 2020. Additionally, based field surveys citizen science sighting program 2004 2020, data spatial distribution 13 conspicuous taxa eight most frequently detected (Aurelia solida, Cotylorhiza tuberculata, Pelagia noctiluca, Phyllorhiza punctata, Rhizostoma pulmo, Rhopilema nomadica, Olindias muelleri Velella velella) Tunisian two ecoregions, Western Plateau. The 17 year survey showed R. A. solida P. noctiluca phenology. revealed increase range punctata distinct phenologies populations ecoregions.