First Record of Species <i>Ostreopsis</i> cf. <i>ovata</i> inthe Water Column on the Montenegrin Coastof the Adriatic Sea (Boka Kotorska Bay)

Distribution of the phytoplankton community and presence of potentially toxic and toxic species were studied on mussel farms in the mesotrophic area of Boka Kotorska Bay as part of the national monitoring of aquaculture farms.In this area, the presence of an epiphytic potentially toxic dinoflagellate species, Ostreopsis cf.ovata, was noticed for the first time.Species of the genus Ostreopsis are marine, benthic dinoflagellates.The high abundance of Ostreopsis species can result in a brownish mucilaginous biofilm forming on various substrates.Additionally, an abundance of toxic dinoflagellates from the genus Ostreopsis is known to cause dangerous respiratory symptoms in humans exposed to aerosols.We performed national monitoring on four mussel farms in the area of Boka Kotorska Bay.During this monitoring at the aquaculture position Drain vrt (BK1), the presence of species from the genus Ostreopsis was recorded for the first time.The abundance of the species reached a value of 10 3 cells/l.The presence of the potentially toxic species from the genus Pseudo-nitzschia was also observed and reached an abundance of 10 4 cells/l.Additionally, among the potentially toxic dinoflagellates, Dinophysis acuta and Phalacroma rotundatum were recorded, although their abundance was lower, reaching values up to 10 2 cells/l.The noticed presence of the toxic species Ostreopsis cf.ovata, along with several other potentially toxic and toxic phytoplankton species, highlights the importance of raising awareness about the necessity of continuous monitoring activities and implementing preventive measures.