The Don Sahong Dam, which is being built by Malaysian project developer Mega First Corporation Berhad, is the second of eleven hydropower dams planned on the lower Mekong mainstream. Scientists and Mekong experts believe the dam will block the main channel passable year-round by fish migrating between Cambodia, Laos and Thailand, threatening vital subsistence and commercial fisheries in the Lower Mekong Basin. In essence, the livelihoods and food security of hundreds of thousands of people are at risk. We find out more from Maureen Harris, the Southeast Asia Program Director of International Rivers, a global NGO working to protect rivers and the rights of communities that depend on them.