摘要：Coastal and estuarine margins are considered natural resources with various functions and are covered by different management and protection tools. In Portugal, the Maritime Public Domain (MPD) aims to regulate property in maritime and coastal areas, assuming that these are public resources of the nation. Little is known, however, about how the MPD considers estuarine margins, which are also valuable, and vulnerable, environmental areas. This article analyses how the concept of MPD applies to the estuarine margins in Portugal. Moreover, as this concept has been subsequently adopted by other countries with close roots such as Angola, Brazil, and Mozambique, this paper also explores if estuaries are further considered in their legislation. For this purpose, it undertakes an analysis of legal documents establishing the MPD, focusing on the definition, types of areas where it applies, the width of the margins, ownership, and use restriction. The findings show that estuaries are considered by the MPD in Portugal and in the similar instruments of the other three countries. Nevertheless, their approaches differ, especially on the width of margins and the flexibility of the ownership regime, suggesting that the potential to protect margins has not been globally reinforced by the countries adopting MPD after Portugal. This study offers new insights on the MPD and brings to the fore a gap in the literature that deserves to be further explored in other countries with different legal traditions and deepening the analysis on the added value for the protection of estuarine margins.
