Blooms of harmful algal species occur along the Washington coast, usually as a fraction of the total phytoplankton population. Although more than 20 potentially harmful species have been identified along that coast,the most deleterious effects on public health and the economy are from Pseudo-nitzschia spp. and Alexandrium catenella. During three surveys conducted in early summer 1996, 1997 and 1998, high concentrations ofPseudo-nitzschia spp. (values of up to 106 cells.l-1, but generall
