Declines in world prawn prices and rising fuel costs are contributing to a shift in fishing practices in the NPF and an increase in targetting of valuable byprduct groups such as bugs and squid. Little research has been done on byproduct in the NPF or in other tropical prawn trawl fisheries. The 2002 catch of byproduct was almost 250 t (AFMA) and comprised of four main groups (squid, cuttlefish, bugs and scallops) of at least eight species. However, the catch of squid alone has been over 400 t in some years (AFMA). The impacts of trawl catch on these groups have never been assessed. This situation is common among many Australian fisheries, where despite the value of byproduct being substantial, they lack sufficient data to undertake specific assessments or even to evaluate options for their management. Thus, there is a need for methods to help identify management options for groups that are data poor like byproduct species in the NPF. New approaches developed in this project will be of value to other Australian trawl fisheries especially the Torres Strait Trawl, East Coast Trawl and Western Australian prawn trawl fisheries. Operational advice from this project would contribute to at least two possible management strategies: the first would be to control fishing on byproduct through species-specific stock assessments. The second would be to control effort on byproduct through spatial and temporal closures, by identifying the key areas and seasons when these byproduct groups are most vulnerable. The most efficient approach to assess the relative merits of alternative management options is to adapt existing trawl impact assessment scenario models to account for non-target catch in their strategy evaluations.