Ecosystem Models with a Range of Complexities to Simulation Test Alternative Management Strategies: Current Research in Australia

The continual methodology development of ecosystem models as decision support tools for marine resources has diversified in Australia. The application of ‘whole of system/end-to-end models’ (the Atlantis framework) and models of intermediate complexity for ecosystem (MICE) assessments differ in terms of emphasis. While the former tends to be all inclusive (currents, biogeochemical process, 3D resolved, ecosystem and human dynamics) and strategic in terms of focus, the latter (the MICE models) are more data driven, rely on advanced statistical model fitting procedures and are tactical in terms of the research focus and applications. Yet, both are complimentary and when used in combination can reduce uncertainty due to similarities and synergies of the model specification process. We present case studies that illuminate the key assumptions, components, and basic underlying numerical specification of these different forms of models. Example applications include end-to-end models for offshore fisheries management (trawl fisheries; tuna and billfish stocks in the Coral Sea) and an example of MICE being applied to evaluate the impacts of water extraction on river catchments and the resultant potential predicted impact on the productivity of a nationally important prawn fishery. We compare and contrast these ecosystem models and their utility as decision support tools.