The northern prawn fishery has been subject to management since the early 1970s in an attempt to control the expansion of effort and prevent the overexploitation of the resource. Many of the management policies developed over this period have proved to be ineffective in controlling effort. Moreover, the increasing cost of management and the need to avoid costly and ineffective measures will lead to increasing demands for analysis of the cost effectiveness of such policies. In order to assess the effects of current and alternative management policies on both effort and profitability in the fishery, a mathematical programming model of the fishery was developed in the Bureau's Fisheries Economics Research Section. This report outlines the model and assesses the short and long term effects of the current and alternative management policies on the fishery.