Significant process is being made with existing projects focusing on the Eastern Tuna and Billfish fisheries (ETBF), but the need to develop and test suites of stock indicators with associated reference points and decision rules for use by the FAGs for each fishery remains, particularly for the Southern and Western region (SWTBF). The need is also urgent, given the imminent introduction of TAE/TAC based management plans and the need to formally evaluate them on an annual basis.

Given the potential difficulties and limitations of using only CPUE as an indicator of stock status there is a need to also consider other indicators, e.g. ones which might reflect local depletion, an issue which is of real concern. Standardisation of such indicators also needs to be considered. Different indicators (e.g. CPUE or mean length in the catch) reflect different aspects of the population dynamics, and there is increasing recognition of the value of considering a suite of indicators rather than relying on a single one. There are currently only limited and relatively unsophisticated frameworks for combining information from several indicators. There is a need to develop this further, and to design defensible and robust frameworks to use in management decision-making. There is also a need to test the robustness of suites of indicators within the context of a feed-back management loop rather than simply in a non-feedback sense.

Although this work is needed for, and will focus on the management of the domestic fisheries, there is an international need for this research. Tunas and billfish harvested in the SWTBF form part of the Indian Ocean stocks which fall under the remit of the Indian Ocean Tuna Commission (IOTC). The research proposed here was identified as a high priority task at recent IOTC Working party meetings.

Stock assessment is a set of tools and methods generally used to assess the status of wild capture fisheries stocks. They range from complex statistical and mathematical models, to simple, almost back of the envelope, methods. They are used to predict population size, quantify the impact of fisheries on the population and in some jurisdictions, provide key outputs needed in harvest strategies. There is a diverse range of methods in a field where practitioners have tended to produce home-grown tools in their favourite code languages (R, Fortran, C++, Visual Basic, ADMB etc.). The use of a specific model or method is often historical rather based on an objective evaluation of options e.g. the risk-cost-catch framework (see Method references). In recent years changes have occurred allowing some shift away from previous approaches:
• More off-the-shelf methods, with a diverse range of flexible features, have become available and some uptake has occurred e.g. Stock Synthesis (SS) (http://nft.nefsc.noaa.gov/SS3.html)
• There has been some convergence of language tools using the open source model (e.g. ADMB, Gnu and R)
• Stock assessment tool kits have become freely available e.g. the NOAA fisheries toolbox (http://nft.nefsc.noaa.gov/index.html)

However, in many cases it is still standard practice in Australia to develop home-grown models. Although this is not in itself an issue, it does not always allow for synergies and more cost effective practices. For example, it has become standard practice in the USA to have a model developed and maintained by a team, have it independently tested and then made available as an off-the-shelf GUI driven tool. Many stock assessment scientists now use these tools. In Europe, ICES also tends to use standard approaches.

There is a real need for a more strategic view of which framework Australia should adopt in the present climate of:
• Fewer finance and capability resources
• Data rich to data poor fisheries
• Small and large fisheries.

This review does not preclude the use of specific modelling.