Agua Dulce. 02/02/08; Sonora; 39 ha; 31°55'N 113°01'W. Located within the Biosphere Reserve Del Picante y Desierto de Altar, which highlights the only riparian ecosystem of the region, Sonoyta river, considered of binational interest and shared between the USA and Mexico. At present, there is a mutual interest in establishing indicators for its management and conservation. Agua Dulce is a 3km stretch of the Sonoyta where water comes to the surface, creating conditions of an oasis in a desert. Among the main species found in the site is the Pupfish (Cyprinodon macularius), listed as endangered by the US and as endemic and endangered in Mexico's legal system. There is a considerable presence of the turtle species Kinonsternon sonoriense longifemorale. The resident and migratory bird species that use the Pacific Flyway find in Agua Dulce a habitat of importance for food, shelter, resting and reproduction. Agua Dulce is characteristic for retaining water throughout the year, acting as the main source of water for wildlife in the area, and supporting an excellent biological diversity. Ramsar site no. 1813. Most recent RIS information: 2008.