The Government of Bangladesh recently declared three new wildlife sanctuaries for endangered freshwater dolphins in the world\'s largest mangrove ecosystem — the Sundarbans, according to the Wildlife Conservation Society (WCS) whose conservation work helped pinpoint the locations of the protected areas. The sanctuaries, which were officially declared on January 29, will protect the last two remaining species of freshwater dolphins in Asia: the Ganges River dolphin and the Irrawaddy dolphin. Although there is no global population estimate for either species, both have disappeared from major portions of their range. However, both species occur in the Sundarbans in sufficient numbers, which may serve as a global safety net for preventing their extinction. The three wildlife sanctuaries safeguard 19.4 mi (31.4 km) of channels with a total area of 4.1 sq mi (10.7 sq km). The locations and sizes of the sanctuaries in the Sundarbans were determined according to a study conducted by WCS and Bangladesh Forest Department and published in the journal Oryx in 2010. The study found that the habitat of Ganges River and Irrawaddy dolphins were clumped in waterways where human activities are most intense. \"Declaration of these Wildlife Sanctuaries is an essential first step in protecting Ganges River and Irrawaddy dolphins in Bangladesh,\" said Brian D. Smith, Director of the WCS’s Asian Freshwater and Coastal Cetacean Program, and first author of the study. \"As biological indicators of ecosystem-level impacts, freshwater dolphins can inform adaptive human-wildlife management to cope with climate change suggesting a broader potential for conservation and sustainable development.\"