The 15th International Conference on Harmful Algae HAB2012 aims to address all issues related to the causes and effects of marine and freshwater harmful micro- and macro-algae and to serve as a forum for exchanging research outcomes and relevant ideas between researchers, industries, governments and interested parties. The Conference will address the following topics of interest: Population dynamics of Harmful Algal Blooms Time series of HAB events: Climatic and anthropogenic induced impacts Impact of HABs on marine food webs and ecosystem structure and function Biological interactions: allelopathy, mixotrophy, parasitism, symbiosis, bacteria and viruses New regional HAB events Inland Seas and HABs Introduction of allien species and HABs Cyanobacterial ecology, physiology and bioactive compounds Genomics and genetic diversity of HABs Toxins: chemical structure and synthesis, detection and analytical methods Novel sensor technologies for bio-sensing applications in HAB research and monitoring. Harmful Algae culture collections Management, mitigation and public outreach for HABs