Ecosystem-scale (D1.1) : Discarding of aquatic organisms is a global problem in the world’s fisheries. The present document attempts to understand why discarding occurs, how discarding can be reduced, the economic and ecological effects of discarding, as well as how these data are used in stock assessments and ecosystem models. The document pays particular attention to European fisheries and the gradual elimination of discards in these fisheries through the introduction of the reformed Common Fisheries Policy.