The Northern Adriatic Sea is the area of the Mediterranean Sea where eutrophication and episodes related to harmful algae have occurred most frequently since the 1970s. In this area, which is highly exploited for mollusk farming, the first occurrence of human intoxication due to shellfish consumption occurred in 1989, nearly 10 years later than other countries in Europe and worldwide that had faced similar problems. Until 1997, Adriatic mollusks had been found to be contaminated mostly by diarrhetic shellfish poisoning toxins (i.e.
, okadaic acid and dinophysistoxins) that, along with paralytic shellfish poisoning toxins (i.e.
, saxitoxins), constitute the most common marine biotoxins. Only once, in 1994, a toxic outbreak was related to the occurrence of paralytic shellfish poisoning toxins in the Adriatic coastal waters. Moreover, in the past 15 years, the Adriatic Sea has been characterized by the presence of toxic or potentially toxic algae, not highly widespread outside Europe, such as species producing yessotoxins (i.e.
, Protoceratium reticulatum
, Gonyaulax spinifera
and Lingulodinium polyedrum
), recurrent blooms of the potentially ichthyotoxic species Fibrocapsa japonica
and, recently, by blooms of palytoxin-like producing species of the Ostreopsis
genus. This review is aimed at integrating monitoring data on toxin spectra and levels in mussels farmed along the coast of the Emilia-Romagna region with laboratory studies performed on the species involved in the production of those toxins; toxicity studies on toxic or potentially toxic species that have recently appeared in this area are also reviewed. Overall, reviewed data are related to: (i) the yessotoxins producing species P. reticulatum
, G. spinifera
and L. polyedrum
, highlighting genetic and toxic characteristics; (ii) Adriatic strains of Alexandrium minutum
, Alexandrium ostenfeldii
and Prorocentrum lima
whose toxic profiles are compared with those of strains of different geographic origins; (iii) F. japonica
toxicity. Moreover, new data concerning domoic acid production by a Pseudo
strain, toxicity investigations on a Prorocentrum
and on presumably ichthyotoxic species, Heterosigma akashiwo
, are also reported.