Suivi des microalgues planctoniques toxiques dans les zones de production, d'élevage des mollusques bivalves et d'exploitation des oursins du nord de la Tunisie

Abstract

Within the monitoring program in the shellfish and urchin harvesting areas of the North of Tunisia, the harmful microalge detected during the period from September 1996 to September 2003, were: <Dinophysis> spp and <Prorocentrum lima> which are associated to the production of diarreheic toxins or DSP (Diarrheic Shellfish Poison). These microalgae were occurred particularly in semi-enclosed areas like the North lake of Tunis and the lake of Bizerte while toxic phytoplanktonic species were in general absent along the coasts of the Bizerte zone and western coasts of the gulf of Tunis, from Kalaât El Andalous to Raoued. Bioassay tests recorded positively on clams were attributed mostly to the presence of these microalgae in the plankton, particularly from september to december and march.