Two factories that process pilchards for bait and human consumption have recently been established in Port Lincoln, however a large proportion of the current harvest is still used to feed caged tuna (Ward et al. 2000; Davidson et al. 2000).

Over the last two years, considerable progress has been made towards the development of a manufactured feed for tuna mariculture. Skretting Australia has obtained successful outcomes from a pilot scale commercial trial. Research is increasingly focussing on matters relating to refinement (improved acceptance, better conversion rates) rather than on the identification of suitable feeds (S. Clarke, SARDI, pers. comm.). Over the next 2-3 years it is expected that the commercial use of artificial diets will increase, with a concomitant decrease in the use of fresh/frozen pilchards. The Tuna Industry has recently discussed bringing a pelleting plant on line in Port Lincoln in 2004/05. Such developments will result in a contraction of the market for South Australian pilchards and may impede further development of the industry.

Future development of the South Australian pilchard industry must involve increased utilisation of inter-state and inter-national markets for recreational bait and human consumption (Ward et al. 2000; Davidson et al. 2000).

As South Australian pilchard fishing grounds are often located 12-24 hours steaming away from local ports (cf 2- 3 hours in WA), the quantity and quality of product supplied to processing factories and markets for bait and human consumption will be largely determined by nature and quality of the at-sea post-harvest handling procedures (Ward et al. 2000; Davidson et al. 2000).

This project will occur in three phases:

Phase 1 (a) An audit of the SA pilchard fleet to assess current practices, quantify on-board processing gear, determine the capacity for improving the latter and assess onshore facilities capacity to process pilchards.
(b) An assessment of the marketing issues as they relate to the capacity of the Industry to develop new processes/products.

Phase 2 Once these are completed, the following will be carried out to optimise the handling procedures used in the South Australian pilchard fishery:
(a) An investigation of the biological and ecological factors that affect the rates of deterioration in pilchard quality in the immediate post-harvest period (i.e. net to processing factory); and
(b) Development of options for alternative handling procedures that optimise pilchard quality and economic return.

To achieve these objectives, information is needed on spatial and temporal variation in the biochemical composition of South Australian pilchards, especially with regard to the lipid:protein ratio and the free fatty acid content. These components are useful indicators of fish condition and the deterioration rate in fish quality during post-harvest handling (Fitz-Gerald and Bremner, 1994, NSC project 6). Knowledge of the taxonomic composition and biochemical characteristics of the gut contents of the South Australian pilchard is needed as these factors have been shown to affect the rates of deterioration of planktivorous pelagic fishes in the immediate post-harvest period (Stenstrom, 1965, Goldberg and Raa, 1980, Dr Bjordal Asmund, Norwegian Institute of Marine Research, pers. comm..; Mr Ian Wells, Seafood Services Australia, unpub. data).

Phase 3
A Cost-Benefit Analysis of the various processing options will have to be undertaken to assess the potential benefit of any changes in gear/practices. In order to do this a financial survey of licence holders, including measures of financial performance for the “average licence holder” will have to be carried out, and measures of economic performance of the fishery derived (i.e. gross value of production (GVP), economic rent, etc). This will be used to develop a model of the fishery linking biological and management parameters (CPUE, days fished, etc.) with the economic characteristics of the fishery. The model will be used to derive a baseline scenario, reflecting existing operator and fisheries management practices which will then be compared with scenarios reflecting the various processing options developed during the study.

The FRDC Review of Fisheries Habitats stated that “we must know where and what must be conserved for sustainability of fisheries and mariculture, before we determine why and how to do it”. At present key uncertainties exist concerning both the relative values of fisheries habitats and the effects of human disturbances at both regional and local scales. As a result, the FRDC Review found that strategic R&D is needed to overcome the poor ability to predict and manage such disturbances. Specifically, the collection, interrogation and extension of new and existing fisheries and habitat data at scales useful to management are required.

While it is generally known which habitats fish are found in association with, the critical factors which govern fish-habitat usage are poorly understood. In the absence of knowledge about why fish are utilising specific habitats, techniques are required to provide managers with information about the relative importance of different habitats and an ability to predict the impact of different pressures on these habitats. A Habitat Suitability Modelling approach is an effective means that can be employed to enable fisheries managers to identify the spatial component of fish-habitat links and make informed decisions on the management of habitats.

1. Implement an age-structured stock assessment model. Stock assessment models that incorporate catch-at-age data and annual fishery-independent estimates of spawning biomass are powerful tools for optimising management strategies for fisheries resources that undergo large inter-annual fluctuations in abundance (Cochrane 1999). The need to implement the WA age-structured stock assessment model in SA is pressing (Fletcher 2000) as there is considerable pressure to further expand the rapidly growing fishery and a clear responsibility to ensure the resource is managed sustainably.

2. Develop a reliable and accurate age-determination method. Knowledge of patterns of age and growth is central to the development of strategies for the sustainable management of clupeoid populations (Cochrane 1999). The major factor limiting current understanding of the age and growth of SA pilchards is the absence of a reliable and accurate age-determination method (Fletcher 2000). The development of a valid ageing protocol has been impeded by lack of data from juveniles (Ward et al 1998). A reliable and accurate method for determining the age of SA pilchards is needed to implement the WA model.

3. Estimate the age structure of the commercial catch. Age-structured stock assessment models require reliable estimates of the age structure of the commercial catch and/or population (Cochrane 1999). Otoliths collected from the SA fishery since 1995 and by the fishery-independent means since 1998 provide an opportunity to assess (1) the validity of the age-determination method developed in objective 2 and (2) the degree to which catch-at-age data reflects the age structure of the population. Reliable estimates of the age structure of the commercial catch and/or the population are needed to implement the WA model.

The mass mortality events are very economically and ecologically damaging. Economic damage occurs acutely in the short-term due to the need to close the fishery during events and damage also occurs in the longer term owing to the removal of large numbers of fish during the event.

No model exists of the spatial propogation of a viral epidemic in an exploited fish population, we will derive such a model. This model will be aimed less at predicting the spread of a particular mass mortality event and more at the understanding of the dynamics of the event. Using the model we will be able to assess hypothesises concerning the factors which control the mass mortality and hence focus future study on the most sensitive processes. The model will also show the conditions under which these events may recur. We will also be able to assess the potential for management intervation to halt an ongoing epidemic or prevent further outbreaks. The model will also integrate all the aspects of the spread of the mass mortality events, showing linkages within the existing data and showing those areas for which adaquate data is lacking.

It should also be noted that damaging epidemics among wild caught and farmed marine fisheries are not infrequent and that modified versions of the model may have future applications to other fisheries.

Understanding the influence of environmental effects on recruitment is an important aspect of fisheries stock assessment (and hence sustainable management) to help interpret whether fluctuations in recruitment are due to environmental effects or to the impact of fishing on the spawning stock. In many cases, the effect of breeding stock cannot be detected unless environmental effects have been taken into account. At present the measure of variation in the strength of the Leeuwin Current along the WA coast from Shark Bay to Esperance is based on monthly and annual mean sea levels at Fremantle, which are highly correlated with sea levels at other locations and have few missing values. The impacts of this and other environmental factors such as westerly winds are presently being examined in isolation rather than obtaining an overall measure of the impact on the circulation. This project will integrate these separate oceanic and atmospheric processes into circulation models and thus result in improved estimates of ocean currents, water temperature and salinity for regions adjacent to important fisheries, providing a better understanding of the effects of environmental variability on recruitment as well as better prediction of recruitment levels.

The current assessment of the impact of the breeding stock on the level of recruitment in the western rock lobster assumes that larvae hatched from all areas contribute to the settlement at each location. Although extensive mixing of larvae during the larval phase occurs, it is possible that larvae hatched from certain areas may contribute proportionally more to the puerulus settlement in different regions. This project will provide an improved understanding of the relative importance of the breeding stocks from different regions, enabling better assessment of the impact of the breeding stock and an improved stock-recruitment relationship which is fundamental for the proper management of the fishery.

There is therefore a need for a physical oceanographic analysis tool that can be used to test theories on the influence of favourable/unfavourable larval advection, or temperature, or larval mortality. A well understood physical/biological interaction would enable efficient ocean and fisheries observation and monitoring programs to be established to maximize the skill of larval survival predictions.