Islas Marietas. 02/02/04; Nayarit; 1,357 ha; 20°42'N 105°34'W. Reserva de Biosfera. Lying off the coast of Nayarit, in Bahía de Banderas, the archipelago consists of two small islands and two islets of volcanic origin. The wind, sun, rain and waves have transformed the substrate, creating various settings that produce an enormous biodiversity. The Islas Marietas are home to a large variety of resident and migratory seabirds, including brown boobies (Sula leucogaster) commonly known as motmots, seagulls and pelicans. The archipelago is also important for the breeding of some marine species like the Humpback whales (Megaptera novaengliae) and the Olive Ridley Sea Turtle (Lepidochelys olivacea). The main threat to the site is the "Escalera Náutica del Golfo de California" project which would imply the building of marinas and other associated infrastructures (hotels, airports, etc.), as well as the increase of the number of boats and visitors sailing around or coming to the islands. The archipelago was recently declared a Special Biosphere Reserve and a National Park. Ramsar site no. 1345. Most recent RIS information: 2004.