After our message to Phycotoxins on May 28, a series samples from Mauritania, arrived at the laboratory of Instituto Espanol de Oceanografia in Vigo. HPLC analysis for PSP toxins were run in this laboratory and AOAC mice bioassays were carried out in the European Communities Reference Laboratory on Marine Toxins also in Vigo.
Samples of different tissues of monk-seals (liver, muscles, spinal cord) were analysed by HPLC for the detection of PSP toxins, and only very small peaks, coincident with the retention time of GTX1, neoSTX and dcSTX were observed, while mice bioassays were negative or, in same cases, they died near the detection limit.
Samples of other marine organisms like bivalves, goose barnacles and some fishes were also analysed giving negative values, except the viscera of some fishes that showed similar HPLC profiles and bioassay results than seals tissues.
HPLC analysis on samples from a non clonal culture of Alexandrium minutum isolated from a water sample off Cabo Blanco shown the typical toxin profile for this species having, in decreasing importance GTX4, GTX1, GTX3, GTX2, and perhaps traces of Cx. The presence of this toxic dinoflagellate is not reflected in the toxin analysis of tissue samples.
As a conclusion, with the data obtained from these analyses we cannot prove that the monk seals kill was due to PSP.
Jose M. Franco CSIC, at Instituto Espanol de Oceanografia. Vigo