Weekly Occurrence of Gymnodinium catenatum and Paralytic Shellfish Poisoning in the Mediterranean Shore of Morocco

Weekly monitoring for the presence of Gymnodinium catenatum and PSP toxins in mussels (Mytilus galloprovinciallis) harvested on the growing site in Fnideq on the Mediterranean Moroccan coast was carried out from 2010 until 2012. The enumeration of G. catenatum cells in water was conducted using the light inverted microscope. Monitoring of PSP toxins levels in mussels was achieved using the mouse bioassay (MBA) method and toxin's profile was performed by HPLC/FD in a selected sample.

The results showed a correlation between the evolution of G. catenatum cells concentration and the PSP toxin level accumulated in mussels. The appearances of G. catenatum and PSP toxin concentration increases were observed at different periods, between January and February 2010, in September 2010 and between November 2011 and January 2012.

Liquid chromatographic analysis revealed a composition reflecting G. catenatum profile composed mainly of toxins from the N-sulfocarbamoyls family, as well as the presence for the first time in Morocco of the hydroxybenzoates analogues of saxitoxin, so called GC-toxins, which have been recently detected in Australia strains of G. catenatum.