Implementation of ecosystem-based fishery management requires sound knowledge of food webs if the indirect effects of fishing on trophic structure are to be understood. There is an urgent need to construct a quantitative food web so that we can understand the ways in which the marked declines in the abundances of important fish species off the lower west coast of Australia, which led to the recent closure of the metropolitan commercial fishery, are likely to have impacted on the ecosystem. While there are sound dietary data for most of the more abundant and important species in this region, no such data are available for Snapper (Pagrus auratus) and Silver Trevally (Pseudocaranx dentex). Snapper was a primary target species for commercial fishers, and Snapper and Silver Trevally both continue to be of great importance to recreational fishers. Sound dietary data for these species, which take into account the ways in which their diets change with body size and season, are essential for the construction of a reliable food web. There is a need to combine the new dietary data for these species with those that were collated in the database developed in FRDC 2002/016 and with the results from more recent studies, converting them into common dietary categories, size categories and a common format before they can be used to construct a reliable food web. The opportunity exists, while Ian Potter remains actively involved in research, to apply the experience and knowledge that he and Margaret Platell possess (noting that these two biologists have been involved in collecting much of the available dietary data for the demersal fish species of south-western Australia) to bring together the results of approximately 15 years of research to create a food web for this region that will be invaluable for future research and management.

The two current FRDC supported projects investigating the WA dhufish conducted at the Fremantle Maritime Center and the School of Biological Sciences at Murdoch University have identified various fish health issues for the species. In some cases these fish health issues will have implications for wild stocks of the WA dhufish and in others they may compromise the ability to commercialise the culture of the species.

Whilst health problems identified so far have been controlled to some extent in the hatchery, the ability to control these in a commercial grow-out operation will be very difficult unless a thorough understanding of the life history of the infesting organisms and the relationship to their host is known. Similarly, improved knowledge of the causal mechanisms of exophthalmia syndrome are required to permit prevention and treatment measures.

Staff at the Fremantle Maritime Centre, the Fisheries Department of WA, or the School of Biological Sciences at Murdoch University do not have the resources to quantify disease causal agents and preventative measures for the WA dhufish.

A recent report of the National Task Force on Imported Fish and Fish products (the Fish Task Force report) noted that there is a serious shortage of aquatic animal health specialists in Australia. The report identified a need to provide a continuum of expertise in this field to support developing aquaculture industries. A recent response to this issue from the Office of the Australian Chief Veterinary Officer (OCVO) emphasises that there is a considerable need for more veterinary training in fish health. This includes the development of standard diagnostic techniques for diseases of aquatic animals and the development of contingency plans for the management of aquatic disease and pest outbreaks. The proposed project addresses these issues.