The Rio Doce (Doce River) is one of the most significant waterways in southeastern Brazil, stretching more than 835 kilometers through the states of Minas Gerais and Espírito Santo. The river and its watershed encompass approximately 84,000 km² and support a population of roughly 3.5 million people across 226 municipalities. The basin is recognized as a conservation hotspot with exceptional biological and sociocultural diversity, including four indigenous territories and communities of artisanal fishermen whose traditions are deeply tied to the river. The lower course of the basin alone supports an estimated 199 fish species, making it one of the most ichthyologically diverse river systems in Brazil. The watershed drains through the Vale do Aço region and is bordered in part by the Rio Doce State Park, a protected Atlantic Forest remnant that includes a remarkable system of lagoons. The river's ecology has been profoundly shaped by both its natural richness and, more recently, by significant environmental pressures.