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.