Discarding is considered by many as an important problem in world fisheries. In many regions, data collection onboard commercial vessels has intensified, and the understanding of both human and ecological drivers of discards is improving quickly. Discarding patterns vary widely across regions, fisheries, gears, and species. Fishers' responses to regulations and markets explain these complex patterns, on top of resource availability partly driven by environmental fluctuations. This expanded knowledge base provides an appropriate basis for discussing the discard mitigation measures proposed in various settings. In September 2012, a theme session was convened at the ICES Annual Science Conference in Bergen, Norway, to discuss these issues. This themed set of articles includes several of the studies presented at the theme session. Owing to the wide diversity of drivers and reasons for discarding, no single management measure or even framework is expected to address the issue. Rather, discard mitigation measures need to be tailored to each particular fishery, or even species within a fishery, and the effectiveness of solutions is greatest when they are used in combination with other approaches. Bottom-up approaches to bycatch and discard management, which involve incentive-based solutions to bycatch problems, were agreed to be the most promising.