The European Union has agreed that, by 2020 at the latest, all fish stocks should be exploited at sustainable levels. In practice this means taking the highest possible amount of catches from the sea without affecting the long-term productivity of the stocks. This is known as the maximum sustainable yield (MSY).
In the North-East Atlantic and adjacent waters (North Sea, Baltic Sea, Skagerrak, Kattegat, West of Scotland Sea, Irish Sea and Celtic Sea), EU fisheries ministers set overall catch limits based on scientific advice. These total allowable catches (TACs) are then divided into national quotas, which set limits on the amount of fish that can be caught.