Bycatch is the unwanted or non-target part of the catch taken by fishermen. It is either discarded at sea or used for human or animal consumption. The capture of bycatch may pose a threat to species diversity and ecosystem health because this part of the catch is usually unregulated. In tropical shrimp-trawl fisheries, bycatch often consists of juvenile food-fish species and is therefore a threat to food security and sustainable fisheries production. Bycatch is a global problem that must be addressed. This Guide to Bycatch Reduction in Tropical Shrimp-Trawl Fisheries is designed for fishermen, net makers, fishing technologists and others interested in a practical guide to the design, use and operation of effective bycatch reduction devices. Fishery managers, policy-makers and legislators will find this guide useful to help develop specifications governing the design and application of these devices in a shrimptrawl fishery. The issue of bycatch is not going away and scrutiny of fishing activity is increasing. All fishermen are strongly urged to use appropriate bycatch reduction measures to help maintain the productivity of the fishery and the long term prosperity of the fishing industry. By responding appropriately, fishermen can help to protect the marine environment and assist global food security both now and in the future. Also published in French and Spanish.