Arrecife Alacranes

Arrecife Alacranes, Scorpion Reef in English, is a coral reef far out in the Gulf of Mexico, roughly 120 to 140 km north of Progreso, on the Campeche Bank. It is the largest coral structure in the southern Gulf, and the protected area around it covers about 333,768 hectares. Within the reef lie five low sandy islands: Isla Pérez, Isla Desterrada, Isla Pájaros, Isla Chica and Isla Muertos, also called Desertora. Isla Pérez is the only one with permanent residents and the only one where visitors may land and camp.

The reef has long been a hazard to shipping. In 1847 the British mail steamer Tweed, sailing from Havana to Veracruz, was wrecked here with the loss of 72 lives. The lighthouse on Isla Pérez, often said to have been a gift from Queen Victoria, was in fact ordered by Mexico's communications ministry in 1899 and finished in 1901; the confusion probably comes from its British maker, Chance Brothers of Birmingham. A small navy detachment and lighthouse keepers rotate on the island, and CONANP, the federal protected areas agency, runs a field station. The reef was declared a national park on 6 June 1994, joined UNESCO's network of biosphere reserves in 2006 and became a Ramsar wetland in 2008.

CONABIO has recorded more than 1,100 species here, including 34 corals, among them elkhorn and staghorn coral, and the sandy islands are used by at least 116 bird species, among them masked boobies and a colony of magnificent frigatebirds that makes the reef an Important Bird Area. Four of the world's seven sea turtle species have been recorded, and turtles nest on the beaches from June to October. Lobster and grouper fishing here supports hundreds of fishing families. Getting here is an expedition: there are no ferries, only private or chartered boats from Progreso that take three to five hours each way, so trips usually last two or three days, sleeping on board or camping on Isla Pérez.