Abundance estimates are used both directly and indirectly in stock assessment processes to support fishery management. Australia’s fisheries research agencies all estimate fish population abundance in some way. These include genetic and conventional tagging, acoustics (active and passive), trawl and egg surveys, as well as using proxies of abundance such as catch. Each of these methods have benefits, biases and caveats linked to the method and to the fish species being assessed. For example, differences between life history and habitat can make an abundance estimation method that has worked for one species unsuitable for another. As the application of each method of estimating abundance is potentially species/scenario specific, potential use by researchers and managers can be fraught.

In developing or proposing an abundance estimate for use in fisheries assessment, researchers must have a clear understanding of the assessment framework in order to make sure that an abundance estimate can be used. Claims such as “this time series can then be used in stock assessment” must be verified by funding agencies (particularly beyond FRDC) and defensible. Proliferation of abundance estimation methods without links to the assessment process will not yield an expected benefit beyond knowledge accumulation.

A project is needed to capture the range of methods of estimating abundance for management purposes, and specify the conditions of use, limitations and readiness level for operational use. A decision tree and methods ‘toolbox’ that describes the techniques, their relative strengths and weaknesses will help researchers and managers identify the best suited abundance estimate approach, and guide research effort to overcome known weaknesses.

The development of a ‘toolbox’ of techniques would be used to inform:
1. techniques available to estimate abundance
2. suitability of them to different conditions such as life history, and data availability
3. requirements of the technique such as methods used, prerequisite expertise, data and cost; and
4. circumstances under which the technique can be used.
This project would also identify potential new approaches and technologies that might complement or replace current ones.