Occurrence and toxicity of the dinoflagellate Alexandrium catenella in an Ionian bay of Sicily

First data on Alexandrium catenella (Dinophyceae) and its co-occurrence with A. minutum are reported in an Ionian bay of Sicily (Syracuse), hosting shellfish aquaculture activity. The study arises from an Italian national project 2010-2013 on algal toxins contaminating water and fish products, supported by the Italian Ministry of Health. Evidence of the occurrence of A. catenella in surface waters of the Syracuse harbour is provided, as a new record for the Mediterranean area, through both microscopy and molecular data. A recent introduction of Alexandrium catenella in this Ionian site is hypothesized and toxin profile is traced from cultured clones.