Identification and Mapping of Harmful Algal Cysts in the Puget Sound

Paralytic shellfish poisoning (PSP) has become a significant problem in Puget Sound causing repeated closures of shellfish beds, which affect both commercial and recreational harvests.  In addition, the increased frequency of such events may have both ecological and human health implications.  Alexandrium sp .is one of the primary dinoflagellate algae responsible for producing toxins that cause PSP in this region.  When environmental conditions become favorable, resting cysts of Alexandrium sp. bloom, releasing the toxins (Coxetal, 2008).  These cysts have been found in various regions  of the Puget Sound and identified morphologically  as Alexandrium catanella.  There has, however, been very little definitive confirmation of their identity, as this requires molecular techniques.  We have isolated individual cysts from four sites in Puget Sound and used  the polymerase chain reaction (PCR)   to confirm their identity as Alexandrium tamarense.    Resolving this taxonomic uncertainty will allow us to both accurately map the spatial distribution of the cysts, as well as better understand the timing and mode of their introduction to the Puget Sound Basin.