Stock assessment

Research focus

Assessment of the status of fish stocks is fundamental to ensuring the sustainability of fish stocks and the commercial, recreational and aboriginal fisheries that depend on these resources. Stock assessment is therefore critical in supporting the Department of Primary Industries Strategic Outcome – Sustainable Resources and Productive Landscapes. Stock status is assessed relative to management objectives specified in the Fisheries Management Act, Share Management Plans, Fisheries Management Strategies and increasingly, within Harvest Strategies. A variety of assessment methods and tools are used to estimate the current stock biomass relative to limit and target reference points specified in management plans and harvest strategies. Limit reference points represent the level of stock abundance below which recruitment to the stock is severely compromised and a fundamental objective of fisheries management is to maintain stocks above this level. Target reference points represent stock levels that are associated with management objectives concerning desirable economic and social outcomes for stakeholders.

Assessment methods range from relatively simple analyses of catch and fishing effort through to complex models that include data about fish biology (e.g. growth rate, size and age at maturity, fecundity), fishing practices and fishing gears (e.g. gear selectivity, spatial extent of fishing, estimates of discards) and observations of fish populations over time (catch, effort, catch-per-unit-effort, size-composition and age-composition of catches). Data may come from fishery-dependent sources (e.g. commercial fishery logbooks, observer surveys, market sampling, surveys of recreational catch) or fishery-independent sources (e.g. surveys of abundance by research vessels). Consequently, effective stock assessment is reliant on the Fisheries Monitoring program, Recreational Fisheries program and Fisheries Technology program for the information and data that underpins our assessment models. Stock assessment draws on these data and evaluates the performance of fisheries and status of stocks against management objectives and, in particular, limit and target reference points developed by the Harvest Strategies program.

Current projects

The research and assessment program involves the scientists and draws on the results from the projects across each of the programs within the Fisheries Resource Assessment Unit. The overarching stock assessment project, lead by Dr Geoff Liggins, coordinates the preparation of stock assessments by FRA scientists, review process, briefings and consultation with stakeholders and submission of the assessments to inform:

1. determinations of annual Total Allowable Catches (TACs) for NSW commercial fisheries;
2. the biennial Status of Australian Fish Stocks (SAFS); and
3. reviews of recreational bag and size limits for the recreational fishery in NSW.

Key publications

NSW stock status summaries: Stock Status Summary Reports

National stock status classification: Status of Australian Fish Stocks Reports

Status of Australian Fish Stocks NSW Stock Status Summaries: Stock Status Summary Reports