Of the toxins produced by P. parvum, prymnesin-1 and
prymnesin-2 were initially characterized and thus have historically been held responsible for toxicity
to aquatic organisms. However, toxicity may not solely result from
exposure to prymnesins, but from other products such as fatty
acids, fatty acid amides, or toxins yet to be characterized (Schug et al., 2010).
Whereas the adaptive functions of these toxins remain unclear, the
resultant fish kills, thought to be caused by the disruption of ion
regulation in gills, are severe