Marine species are reproducible resource. Maintaining the stock level of marine species and the sustainability of fisheries development become critical issues in current scientific research areas due to the explosion of human population and exacerbation of natural environment. The traditional method that protects the marine species is the single species approach which set maximum sustainable yield (MSY) to prevent over-harvest. However, with the development of technology and comprehension of marine science, the single species approach has been found obsolete and incapable of dealing with problems of severe depletion of fish stocks and escalation of fisheries confliction. Studies show that when regulations are species specific and species are part of a multi-species fisheries, the catch levels of different species are correlated which result in correlation of net return from each species. This paper employ financial portfolio into fisheries, treat fish stocks as assets, model the fishers’ behaviour who face multiple targeting options to predict the optimal targeting strategies. This methodology is applied to New Zealand fisheries that are managed in Quota Management System (QMS) introduced in 1986. Species considered in this research are selected carefully based on two criteria. Efficient risk-return frontier will be generated that provides a combination of optimal strategies. Comparison between results and actual data will be presented. Potential explanations will be given so that further suggestions to fisheries can be made.