A marine protected area (área marinha protegida) is a designated sea zone where human activity is limited to conserve ecosystems, species and habitats, and rules can range from restrictions on certain fishing methods to full no-take zones. In the Azores and other Portuguese waters, these protections can restrict commercial and recreational fishing and are often controversial because they balance biodiversity goals with local fishing livelihoods, which is why disputes over tuna fishing arise. Enforcement and specific rules vary by region and are managed by national and regional maritime and environmental authorities.