This report presents the results of laboratory developments, field experiments and data analyses carried out in the contract MARE/2011/07 - "Studies on the Common Fisheries Policy" - Lot 1 "Reduction of gear impact and discards in deep sea fisheries". The contractual objectives were "(I) to identify and study trawl modification and alternative gear that aim at reducing the impact of the gear on the sea bottom when engaged in deep-sea fisheries, and (II) to identify and study a measure for discard reduction in deep-sea fisheries or fisheries having deep-sea species as a by-catch, pursued with trawls or nets. The measure could consist in gear modifications or catch purification based on the skipper’s strategy to avoid unwanted fish."