Eventualite d'un transfert du phytoplancton toxique des milieux portuaires du golfe de Gabes vers les zones de production de coquillage

Abstract

There is a strong evidence that harbours submitted to an intense maritime traffic receive ballast waters of ship possibly coming from various oceanic regions and parts of the world. The transfer and the invasion of several harmful species via ballast waters tipping and ship fouling have been amply summoned these last times. These introductions can cause many damages to the neighbouring sectors and particularly in zones of shellfish production mainly if the introduced species are constituted of harmful phytoplankton. At the end of a 4 years survey for phytoplankton quality of harbours surrounding the Gabes gulf, some toxic species were inventoried, some of them being new ones in the context of the Gulf phytoplankton flora such as Alexandrium margalefi, A. fundyense, A. insuetum, A. ostenfeldii, Gymnodinium catenaum and Karenia papilionacea. In this survey we tried to follow the evolution of these species, from the harbours areas toward bordering shellfish production areas. There is an urgent need to set up a monitoring program for these transfers .