The release of different organic compounds is dependent on the species forming the harmful algal bloom (HAB) and bacterial species vary in their heterotrophic utilization of these various substrates, the structure of the bacterial community is strongly influenced by the composition of the associated HAB. To this end, this study focused on the temporal shifts in bacterial community profiles in relation to specific phases of a H. akashiwo bloom event. Whilst some research into the morphology, toxicity and physiology of H. akashiwo has been conducted, no research has been conducted to date using high throughput sequencing technologies to ascertain shifts in bacterial assemblages in response to H. akashiwo algal blooms.