on Isla del Carmen, between the lagoon and the Bay of Campeche. The Zacatal Bridge spans the Boca del Carmen, connecting Isla del Carmen to the mainland Atasta Peninsula, which encloses the lagoon on the northwest. The bridge is part of Mexican Federal Highway 180, which runs along Mexico's Gulf coast including down the length of Isla del Carmen. The highway also spans the Boca de Puerto Real as it continues east. Flora and fauna Twenty-nine percent of the lagoon is covered with seagrass. The lagoon was designated as a federally protected area for flora and fauna in 1994 by the Mexican government because of the importance of the biological ecosystems provided by its estuaries. There have been 1,468 identified fauna species found within the protected area of Laguna de Términos; 30 species are endemic to Mexico and 89 are threatened; 132 species are considered to be commercially important. There are 279 bird, 74 insect (considered an incomplete listing), and 34 mammal species identified. At least 367 species of fish are listed. The Usumacinta mangroves extend around the edges of the lagoon where freshwater meets salt, and westward into the lower Usumacinta-Grijalva basin. The Usumacinta distributaries bring higher freshwater and nutrient inflows to the western part of the lagoon, and the mangroves near the outlet of the Palizada are the largest and best developed, with some trees reaching over 30 meters in height. The Pantanos de Centla, a vast seasonally- or permanently flooded freshwater swamp forest, lies east and south of the mangroves. The seasonally-dry Yucatán moist forests lie east of the lagoon. It is a known breeding and nursery area for the yellow stingray (Urobatis jamaicensis); seagrass is reported to be important for its parturition. Campeche and Tabasco hold wetlands consisting of mangrove zones, swamps, and lagoons serving as important habitats for aquatic reptiles such as crocodiles (American, Morelet's, brown caiman). Nationally endangered hawksbill, green sea, and Kemp's ridley sea turtles come on sandy shores to lay eggs especially setting a special protection on Kemp's ridley turtles. Mangroves around the Lagoon of Términos provides a migratory collider for at least 33% of the Mississippi - migratory birds. Of about 134 mammalian species from 27 families present in the area, rare and endangered species include felines (jaguar, ocelot, margay), primates (Geoffroy's spider monkey), and marine mammals including cetaceans and the West Indian manatee. Bottlenose dolphins Bottlenose dolphins (Tursiops truncatus'') are