Fifteen years of Pseudo-nitzschia in an Australian estuary, including the first potentially toxic P. delicatissima bloom in the southern hemisphere

In March 2018, an unprecedented bloom of a species of Pseudo-nitzschia occurred in Berowra Creek, a major tributary of the Hawkesbury River estuary, New South Wales, Australia (max cell abundance 5.7 × 106 cells L−1). Morphological and phylogenetic analysis showed the bloom was dominated by the species P. delicatissima, with toxin characterization by LC-MS confirming one of the seven strains isolated produced domoic acid (DA), at a concentration of 0.34 pg DA per cell.