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 PSP agent Alexandrium minutum from several Galician rias (NW Spain) was obtained by HPLC. The toxin content of cultures of A. minutum is dominated 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 natural populations of Alexandrium from three different Galician rias, where a mixture of A. lusitanicum Balech and A. minutum can occur. Important quantitative differences were found between the three isolates, one being highly and two weakly toxic. The results obtained from these isolates and natural populations of Alexandrium were very similar to those obtained from HPLC analyses of mussels intoxicated during a PSP outbreak in Ria de Ares (Rias Altas) in 1984, confirming that A. minutum (previously identified as Gonyaulax tamarensis Lebour and Alexandrium lusitanicum) was the PSP agent during the toxic outbreak in May 1984. Toxin profiles obtained from natural populations during different PSP outbreaks in different rfas and from cultures are fairly consistent and suggest that at least from the toxin point of view, A. lusitanicum and A. minutum are identical, and that the toxin profile of A. minutum from Galicia can be used as a biochemical marker.