Over the past decade there has been a major decline in the commercial and receational snapper fishery in Port Phillip Bay, the commercial catch declining from 200 t to 40 t. At present, the status of the Port Phillip Bay snapper fishery is in doubt because the relationship between the Port Phillip fishery and the western stock as a whole is unknown. Whether catch declines in Port Phillip Bay are a result of local factors such as overfishing or local recruitment variability, or whether they are the result of change in the migratory dynamics of snapper between Port Phillip and offshore waters, will not be known without new research that is novel in its approach. At present we cannot be certain whether the apparent decline snapper in Port Phillip Bay mirrors a decline in the entire western stock. Imposing management controls is difficult in the face of such uncertainty, and therefore the snapper fishery in Port Phillip is under threat. This project, endorsed by the recent workshop on snapper research in Victoria, aims to clarify some aspects of the relationship between snapper in Port Phillip Bay and the rest of the western stock. Otolith microchemistry is a novel technique that may prove very powerful in answering questions about the origin and migration patterns of snapper in the Port Phillip. In addition, pre-recruit sampling across the Victorian coast will indicate whether high recruitment variability observed in Port Phillip is reflected by the entire stock.

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.

In order to provide sound advice on the merits of alternative measures for recreational fisheries management, it is necessary to determine the effectiveness of each management option availible. In particular there is a need to analyse the available recreational data to quantify and model the relative impact of seasonal and area closures, size limits and bag limits for major target species.

While recreational fishery surveys have been conducted in Victorian bays and inlets throughout the 1980's and 1990s, the data collected have mostly been used to estimate catch and effort. Further analysis of the available data would provide more information to address fundamental management issues such as the appropriateness of size limits, bag limits and seasonal or area closures in different scalefish fisheries managed by Victoria (bays and inlets and coastal waters). Modeling the impacts of these management tools under various fishery and management scenarios will allow Victorian and other state management agencies to make more informed decisions regarding appropiate tools for managing key recreational scalefish fisheries under their jurisdiction.

Reduction of by-catch has been an active area for research in Australia and around the world. The initial focus for research and management has been demersal trawl fishing, where the perception of waste and potential impact has been the greatest. However, the reasons for seeking to reduce unwanted catch apply to all fisheries, including those using demersal traps.

Demersal fish traps in NSW must be covered with mesh no smaller than 50 mm, and a galvanised hexagonal fencing wire is the most common material. However, many fishers use larger mesh and both 50 X 75 mm and 75 mm hexagonal mesh are in use. Those using and advocating larger mesh have done so to reduce the catch of undersize snapper and other small fish and to decrease sorting times. Other trappers are concerned about the effect of larger mesh dimensions on the catch of valuable species such as wrasses, sweep or bream which all have no minimum legal length (MLL) or have an MLL smaller than snapper.

An understanding of the differences in selectivity of different sizes of mesh on the species caught in fish traps will have a number of uses. This information is essential to determine the cost and benefit to fishers of changing mesh sizes. The selection probabilities for existing meshes can also be used to improve the assessments using age and length composition collected for snapper and bream in NSW. This is particularly important for snapper, where a very large proportion of the fishery is caught close to the MLL. Finally, because wire mesh can be made in a diversity of shapes and sizes, it may be possible to achieve desirable changes in selectivity for some species while not changing selectivity patterns for others.

The overseas speakers have agreed to come, speak at the Congress and speak to at least one other group while in Australia providing there is some assistance with their travel expenses. This is a great opportunity for members of the fishing and aquaculture industry to hear about latest developments in disease research. The proposed presence of these speakers at the Congress has already attracted other experts in marine disease to come to Australia for the Congress and these also will be meeting with special interest groups while here.