Project in brief Blooms of Ostreopsis in coastal areas are a topic of increasing interest, mainly in the Mediterranean Sea, due to the potential hazards that this species of algae might cause to human health and the consequent negative effects on tourism, fishery and aquaculture businesses. In the last 15 years, blooms of toxic dinoflagellates (harmful water microorganisms) belonging to the genus Ostreopsis were observed in temperate and tropical coastal waters in both the northern and southern hemispheres. In the Mediterranean region, blooms of Ostreopsis have taken place withincreasing frequency, intensity and distribution: human mass intoxications have been recorded for the first time in Catalonia (Spain) in 2004, in Genoa (Italy) at the end of July 2005 and more recently along the Tunisian coasts. The M3-HABs project answers to the need of understanding and predicting toxic microalgae blooms occurrence through the performance of common monitoring procedures and protocols making the process cost and time effective and increasing at the same time the knowledge on environmental drivers affecting harmful algal blooms. Specific objective To provide and test a common pan-Mediterranean strategy for monitoring benthic toxic microalgae, through technological improvements in sampling design, data analysis and modelling in order to prevent and reduce risk factors for the environment, human health and economic activities related to the coastal environment Expected Results: • Appropriate caution measures diffused • Common monitoring protocols of toxic algal blooms established • New technologies for species-specific identification and counting developed • Common and effective prediction models of algae blooms produced • Increased awareness of the risks associated to algal blooms