The change in focus of fisheries management towards ecosystem-based management (Pitcher 2001) is a worldwide trend. Within Australia it is particularly evident in the requirements of the Environmental Protection and Biodiversity Conservation (EPBC) Act, and in the development of regional marine plans (RMPs) under Australia’s Oceans Policy. The former requires strategic assessment of the ecological impacts of fishing, including assessing trophic impacts. The latter seeks to integrate management of entire regions through an ecosystem approach that considers impacts from all uses of the marine environment (including impacts of other users on fishery ecosystems). The southeast region is the first to be evaluated under Oceans Policy.

Even without the “stick” of EPBC and RMP, there are good reasons to attempt to synthesize current data and understanding of the SEF ecosystem, and to model the impacts of and on the fishery. Specific questions that need addressing include:
·What changes in the fish community have taken place in the past, and what are the consequences for current fishery production and value?
·What further changes might be expected under planned reduction or elimination of discarding in the SET?
·What are the implications for the fishery of current rapid recovery in seal populations?
·What are the reasons for and impacts of year-to-year variability in the SEF ecosystem (including regional circulation and primary productivity) on distribution and catches of quota species?

This study will provide a set of tools to explore answers to these questions.

Through the research being undertaken in FRDC Project 2000/311, “Development of research methodology and quantitative skills for integrated fisheries management in WA”, it has been recognised that the dietary data available for Western Australian fish are limited and may result in an imprecise specification of the food web. An urgent need to collate the existing dietary data in order to assess their adequacy in developing information on the extent to which fish species predate upon fish and invertebrates, or ingest plant material, has been identified. Ecosystem modelling and monitoring of the “health” of the non-landed prey species will require the development and maintenance of a database containing consistent and comprehensive details of the relative proportions of the prey species in the diets of their predators. Gaps within the resulting database need to be determined and the research methods, that are required to fill these gaps, need to be identified. Without such data on dietary compositions, it will be impossible to ascertain accurately the relationships between species, thereby hampering the development of accurate ecosystem models. The utility of the existing data sets will be considerably enhanced by their collation and synthesis, and the resulting data are considered to be essential for the development of ecosystem models capable of providing the information required to manage fisheries in accordance with the principles of ESD.