Fishing is based on the exploitation of renewable biological resources (economically important organisms) which inhabit inland waters and the seas. Besides fishing, fish farming (or aquaculture) also offers good prospects, in Croatia and across the European Union (EU), as well as globally, so it is a very important factor for the survival of mankind. Excessive exploitation of fish stocks leads to environmental problems, therefore, sustainable fishing is the only solution for future generations to avoid social and economic crises. At present, sustainable fishing is faced with a number of challenges as a result of the climate change. It is impossible to separate fishing from the nature and the environment in which economic activities take place because the management of fishing activities has a strong impact on sustainability and the environment itself. The EU Common Fisheries Policy (CFP) provides the basis for rational and fair fishing activities and an integrated approach to the marine ecosystem. It also aims to overcome numerous challenges facing Europe and the world nowadays, from pollution to excessive fishing, from urbanisation to coastal erosion and climate change. The priority objective of the EU Common Fisheries Policy is to establish a balance between the competitive fishing industry, on the one hand, and sustainable fish stocks and aquatic ecosystems, on the other hand. To this end, the European Commission facilitates intersectoral and cross-border cooperation among all participants in the maritime industry so as to ensure that the development of the European maritime economy is not detrimental to the environment. This is achieved by adapting economic activities to each particular sea basin and, where necessary, by providing common instruments which can help the Member States in the implementation of modern and suitable national strategies. The present paper focuses on the priority axes used to prevent unsustainable exploitation and disruption of the fragile balance prevailing in the marine ecosystems, as well as the competition for the use of marine areas.