The Mesoamerican Barrier Reef System (MBRS or MAR: Mesoamerican Reef) is the world’s largest transboundary barrier reef, encompassing 1000 km of coastline, from the northeast end of the Yucatán Peninsula, Mexico, to the Bay Islands in Honduras. The MAR ecoregion includes oceanic habitats, coastal zones, tropical forests and the Caribbean draining watersheds from four countries: Belize, Guatemala, Honduras and Mexico. The area is extremely important biologically and economically, with coral reefs, seagrasses and mangroves that provide livelihood to many people and also critical protection against damage from hurricanes and tropical storms. Almost two million people live in the ecoregion and some one million depend directly on the integrity and resilience of the reef in order to maintain their lifestyles. The national economies of the four countries substantially bene t from the reef’s appeal as an international tourist destination. Members of different indigenous groups inhabit the region, including Garifuna, Kekchi, Maya, and Creole (Arrivillaga and Windevoxhel 2008).