Commonwealth fisheries have been required to implement harvest strategies in accordance with the recently released Commonwealth Harvest Strategy Policy. The policy specifically requires that a MSE be conducted to demonstrate that each harvest strategy is robust to the uncertainty inherent in the assessment and management of the respective fishery.
In June 2008, the AFMA Board approved a harvest strategy for the SPF, which will be reviewed during 2008/09. In 2007, the SPFRAG and SPFMAC engaged a consultant to review the draft harvest strategy that had been developed for the fishery. Based on the outcomes of that review, which included a quantitative evaluation, SPFRAG and SPFMAC agreed to a harvest strategy. During 2008/09, further testing of the harvest strategy will be undertaken and various scenarios investigated. There is an urgent need to investigate the robustness of the harvest strategy under a range of harvest scenarios and to determine the implications of these harvest scenarios on the wider trophodynamic relationships (through linkages with the CSIRO project). The proposed project will develop an interactive tool that SPFRAG and SPFMAC can use to explore the robustness of the harvest strategy now and in the future.
In 2008, the Australian Fisheries Management Authority (AFMA) developed a harvest strategy for the Commonwealth’s Small Pelagic Fishery (SPF) (AFMA 2008) in accordance with the Commonwealth Fisheries Harvest Strategy Policy (DAFF 2007). Before its completion, an independent review was conducted (Knuckey et al. 2008), which included a management strategy evaluation (MSE). The equations developed for the MSE were used in this report to establish a new MSE. The new MSE was used to further test the SPF Harvest Strategy and to investigate a range of alternative harvest strategies for consideration by the Small Pelagic Fisheries Resource Assessment Group (SPFRAG).
In this report, the sensitivities of the MSE were tested to determine how the various input parameters influenced the outcomes over a 30 year simulation period. A number of management/harvest scenarios were run through the MSE to explore options addressed in the SPF Harvest Strategy for each stock — redbait (east), redbait (west), blue mackerel (east), blue mackerel (west), jack mackerel (east and west treated the same) and Australian sardine (east). Themodel was found to be most sensitive to the steepness value in the stock recruitment relationship and to the value of the instantaneous natural mortality.