This text aims to study the marine fauna (fish, crustaceans, corals, among other animals) in Portugal from the Middle Age to the Early Modern Age (13th -16th centuries). To achieve our purpose, we will use legal documentation (municipal and regia) and literature (travel and knowledge books). We aim, on the one hand to make know the marine fauna and, on the other hand, to analyze the diverse forms of exploitation and management of these resources (fishing, transport, commerce and supply). At the same time, we emphasize conflicts, as well as solutions and policies adopted by communities to manage, preserve and conservation marine fauna.