Laguna de Catemaco

Lake Catemaco fills a basin in the centre of the Sierra de Los Tuxtlas in southern Veracruz, with the town of Catemaco on its western shore. Despite the name laguna it is a freshwater lake: it formed when lava from the San Martín Tuxtla volcano blocked its northern end, and it now lies about 340 m above sea level. It covers about 72.5 km², measures roughly 10 by 12 km, and has an irregular shoreline of about 50 km marked by old volcanic cones. It is shallow, averaging 7.6 m, with a maximum depth of 22 m in the channel between Agaltepec island and the town. Roads run almost all the way round it.

The lake drains through the Río Grande de Catemaco, which drops over the Salto de Eyipantla 11 km downstream. That waterfall has cut the lake off from the rest of the Papaloapan basin for a long time, and five of its fish species are found nowhere else. It is one of the most productive lakes in Mexico, and more than a thousand registered fishermen work it; the usual catch is the small topote, introduced tilapia and the tegogolo snail sold on the malecón. The forest that once covered its watershed has been heavily cut, and sediment now clouds the water. Sean Connery's Medicine Man and Mel Gibson's Apocalypto were both filmed around its shores.

Most visitors see it from one of the many launches that leave the Catemaco docks. The usual trip goes past Isla de las Garzas, where herons, cormorants and kingfishers roost, to Tanaxpillo, the Isla de los Changos. Stump-tailed macaques from Thailand were introduced to the lake in 1974 by the Universidad Veracruzana for conservation and behaviour studies, first on Totogochillo island; a second colony released on Tanaxpillo in the 1980s now has more than 60 animals. The larger island of Agaltepec, with native howler monkeys, is managed by the university for research. Many trips also take in the shrine of El Tegal, where the Virgin is said to have appeared, and the Nanciyaga reserve on the eastern shore.