Increased formalisation of harvest strategies for snapper across Australia’s four main jurisdictions (East Coast, Western Victoria, South Australia and Western Australia) was identified as a national priority (at the National Strategic Planning Workshop for Snapper Research – 1st March 2013). Two key processes were recognised as being fundamental to achieving this: 1. development of a snapper-specific integrated fishery model; and 2. integration of a fishery-independent estimate of abundance. Each jurisdiction is currently at a different level of advancement in their assessment and management capability, with WA leading the way. A snapper model is currently used to underpin the assessment of South Australia’s snapper resource, whereas Western Victoria is in the process of developing their own and the East Coast is yet to develop one. South Australia and Western Victoria are at a level where the development and integration of a DEPM, that would provide a fishery-independent estimate of biomass, would considerably enhance their respective stock assessment programs.

The need for a DEPM is more urgent for South Australia, as recent structural changes in the snapper fishery have compromised the integrity of the time series of fishery-dependent statistics that have been relied on to assess the resource in the past. Fishery-independent estimates of snapper biomass are required to feed into the existing stock assessment model to ensure that future assessments and harvest strategies are developed from unbiased information. This research direction has been unanimously supported by the relevant stakeholders in South Australia’s Snapper Fishery. The Western Victorian fishery is likely to encounter similar issues to South Australia, particularly as their fishery is dominated by the recreational sector where the routine collection of catch and effort data to integrate into the assessment process is often challenging.

Developing a comprehensive understanding of the movement patterns and stock structure of a fish species is crucial for identifying the appropriate scale and strategy for management.

In south eastern Australia, there are several adjacent Snapper fisheries operating in South Australian (SA), Victorian and Commonwealth waters that are managed using different strategies. The SA fishery, currently Australia’s largest Snapper fishery, is divided into contiguous regions whose relative contributions to total catch have changed dramatically in recent years. The extent to which these different regional or jurisdictional populations represent a single or multiple stocks is poorly understood because of the limited understanding of the patterns of fish movement. For example, have the recent high catches of Snapper from Northern Gulf St. Vincent and South East resulted from high levels of biomass built up through local demographic processes or have fish moved in from adjacent regions or possibly even from Victorian or Commonwealth waters? If large-scale movement is involved, it must be temporally complex as it appears to not conform to a regular, annual pattern. The need here is to elucidate the regions of origin and movement patterns of fish that currently contribute to high regional catches in SA to inform about the demographic processes that drive the spatial and temporal variation in fishery productivity. This will point to the appropriate spatial scale for management. It would also provide insight for resource allocation amongst the different fisheries, which is currently being considered by AFMF to improve resource sharing arrangements for Snapper.

Management of the snapper fishery of South Australia has recently attained a level of heightened political sensitivity, reflecting the need to optimise the strategic approach. Nevertheless, from relevant discussions it is apparent that our understanding of the life-history is too poor to predict likely outcomes from suggested regional management strategies.

For this snapper fishery there is a need to optimise management based on a better understanding of the life-history and population biology, particularly with regard movement patterns of adult fish. It is currently unknown the extent to which fish move between different geographic regions, and thus the extent to which such behaviour contributes to the natural processes of sustaining the different regional populations. Such adult movement will determine the extent to which regional populations are independent, discrete, and separate sub-populations. Adult movement and stock structure are fundamental to identifying the appropriate spatial scale at which the population dynamics work, and thus the appropriate spatial scale at which fishery management should be applied.

Industry, in consultation with PIRSA, FRDC and the SA FRAB, specified five-year research priority needs in, “South Australian Fisheries and Aquaculture Five Year Research and Development Strategy”. For Marine Scalefish, priority item 2 (after allocation issues of User Access) was “Stocks Assessment (A): There is an urgent requirement to identify further biological information relating to key species which will lead to better total management of the fishery”, with the first Key Requirement being to “more accurately assess stocks levels of key species”.

Data for optimal and sustainable management, to be used under the restructured management regime, are now available. Needed are cost-effective analysis tools for converting these data to a form that managers and the MSF FMC can apply directly to management decision making.

Requested are yearly estimates of stock performance indicators, recruitment, exploitation rate, and stock biomass, for the key species. This need is being addressed for King George whiting in an FRDC project. Models for performance indicators of other species, notably snapper and garfish are now required.

Cost effective delivery of indicators to fishery managers and the Marine Scalefish Fishery Management Committee (MSF FMC) will be attained by providing the research biologists with a stock assessment model estimation software for analysis of fisheries data. This software should meet three criteria: (1) Use the best available methods of estimating stock management indices, (2) provide confidence bounds for all indicators estimated, and (3) be presented in a user-friendly interface, allowing its use, in conjunction with modellers, by the research biologists who gather the data and write yearly stock assessment documents.