Between 2002 and 2005, WCS partnered with captains of nature tourism vessels (engaged as citizen scientists) to conduct over 2,750 km of scientific surveys. This new knowledge informed us that the Sundarbans is a hot spot for both Ganges River and Irrawaddy dolphins. Today WCS is working with the protected area management agency and local communities to conduct educational outreach and to implement SMART patrols to ensure that fishers comply with regulations prohibiting destructive fishing techniques. WCS’s next surveys, which studied the coastal waters near the vast submarine canyon called the Swatch-of-No-Ground (SoNG), discovered as many as 5,400 Irrawaddy dolphins. Given the 450 Irrawaddy dolphins resident in the Sunderbans, we realized that this area supports the world’s largest population of Irrawaddy dolphins by an order of magnitude. Closer to the head of the SoNG, WCS discovered over 1,200 Indo- Pacific finless porpoises, 600 humpback, 2,200 bottlenose, and large numbers of pantropical spotted and spinner dolphins, as well as a genetically distinct population of Bryde’s whale. By spreading the word that Bangladesh is a global hot spot for dolphins, porpoises, and whales, and linking the survival of these threatened wildlife species to sustainable fisheries and climate change adaptation, WCS created a local constituency for conservation that inspired the government to ask WCS to prepare a proposal for establishing the nation’s first marine protected area.