ON THE BLOOM OF TOXIC DINOFLAGELLATE-CONY AULAX TAMARENSIS IN THE LAGOONS OF CA-PISANI, VENETO, ITALY

An exclusively dense ''bloom'' of potentially toxic dinoflagellate Con yaulax tamarensis Lebour was observed in the lagoons of Ca Pisani (Ven eto, Italy) in summer 1993. The lagoons were influenced by eutrophic w aste waters from intensive culture fish ponds. The density of algae du ring the ''bloom'' attained 2-4x10(6) per litre and biomass - over 100 mg/l. The ''bloom'' was associated with drastic mortality of macrophy tes and fauna, development of nocturnal anoxia, accumulation of organi c matter in water and sulphides in sediments. The probable role of was te waters from coastal ponds in the development of toxic dinoflagellat e ''bloom'' is discussed.