TOXIN PROFILES OF NATURAL-POPULATIONS AND CULTURES OF ALEXANDRIUM-MINUTUM HALIM FROM GALICIAN (SPAIN) COASTAL WATERS

The toxin profiles of three isolates and natural populations of the PS P agent Alexandrium minutum from several Galician rias (NW Spain) was obtained by HPLC. The toxin content of cultures of A. minutum is domin ated by GTX4 (80-90%) and GTX4 (10-15%) with small amounts of GTX3 and GTX2 (less than 3% of each); similar results were obtained for natura l populations of Alexandrium from three different Galician rias, where a mixture of A. lusitanicum Balech and A. minutum can occur. Importan t quantitative differences were found between the three isolates, one being highly and two weakly toxic. The results obtained from these iso lates and natural populations of Alexandrium were very similar to thos e obtained from HPLC analyses of mussels intoxicated during a PSP outb reak in Ria de Ares (Rias Altas) in 1984, confirming that A. minutum ( previously identified as Gonyaulax tamarensis Lebour and Alexandrium l usitanicum) was the PSP agent during the toxic outbreak in May 1984. T oxin profiles obtained from natural populations during different PSP o utbreaks in different rfas and from cultures are fairly consistent and suggest that at least from the toxin point of view, A. lusitanicum an d A. minutum are identical, and that the toxin profile of A. minutum f rom Galicia can be used as a biochemical marker.