This large Wetland of International Importance on Brazil’s north-eastern coast features bays, inlets and estuaries, low and flat areas, as well as extensive mangroves. It covers almost 2.7 million hectares and is connected to four other wetlands of international importance (Cabo Orange National Park; Baixada Maranhense Environmental Protection Area; Amazon Estuary and its Mangroves; and Par.Est.Mar. do Parcel Manoel Luís incl. the Baixios do Mestre Álvaro and Tarol) forming the largest continuous area of ​​mangroves worldwide. The Site is an ecosystem rich in biodiversity: it is the second-most important area in South America in terms of migratory bird numbers. It hosts 50% of all the coastal bird population in Brazil and 7% of all those in South America, including the Hudsonian godwit (Limosa haemastica) and the whimbrel (Numenius phaeopus). In addition, it provides shelter to critically endangered species such as the Hawksbill turtle (Eretmochelys imbricate) and vulnerable ones such as the Caribbean manatee (Trichechus manatus), the leatherback turtle (Dermochelys coriacea) and the Atlantic goliath grouper (Epinephelus itajara). Reentrancias Maranhenses faces natural threats such as strong ocean currents and the advance of sand on the mangrove. However, the main threats are predatory fishing, incidental fishing of threatened species, and the collection of turtle eggs.