In this presentation, we will discuss how tourism development affects the coral reefs and in continuation of this, we will examine the Crown-of-Thorn Starfish invasion around Zanzibar. Reefs sustain human society, such as fishermen's livelihood and they are also a key asset for the tourist industry. However, the reefs are also under pressure from a range of human induced stresses, including the expanding tourism. Would you like to learn more about Sustainable Tourism? Sign up for our online course: Sustainable Tourism - promoting Environmental Public Health? (indsæt hyperlink over titel, hvis muligt https://www.coursera.org/learn/sustainable-tourism You are also welcome to join other MOOCs from University of Copenhagen. (indsæt hyperlink, hvis muligt https://coursera.org/ucph). Flemming Konradsen Professor, Director, School of Global Health, University of Copenhagen