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Diving into sustainability

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Coffin Bay South Australia
Oyster beds at Coffin Bay, South Australia

Fisheries Research and Development Corporation (FRDC), Media Release, 17 January 2022

Consumers are increasingly demanding proof of their seafood’s sustainability and they are turning to a range of seafood certifications, rating programs and indexes to inform their purchases.

Globally, there is a growing number of initiatives to guide consumers. But they are not all created equal, nor do they measure and report on the same parameters.

Reporting on stock sustainability is often cooperatively implemented by governments, either internationally (e.g. the United Nations Food and Agriculture Organisation’s Fishery Status Reporting Process), or nationally (e.g. the Status of Australian Fish Stocks). These programs typically focus on stock sustainability—the capacity of the fished stock to maintain itself at a given level of abundance—rather than on sustainability in a broader sense that might include considerations such as bycatch, carbon footprint or plastic use.

Some schemes provide endorsement for specific fisheries and species, such as the Marine Stewardship Council (MSC) certification, which is highly regarded internationally but comes with costs that not every fishery can afford.

Some programs attempt to provide a broader picture of sustainability, combining assessments of fish stocks with social and economic indicators, ecosystems assessments and management measures.

The scope, scientific rigor and transparency behind the many initiatives can be highly variable, although they all generally involve assessment against pre-set requirements, using fish biomass as a starting point.

To help users evaluate the quality of different programs, the Global Sustainable Seafood Initiative (GSSI) has a Global Benchmark Tool that effectively assesses the assessors. GSSI is a public–private partnership focused on seafood sustainability with over 90 stakeholders industry-wide. GSSI aligns global efforts and resources to address seafood sustainability challenges.

To date, the GSSI has recognised nine sustainability certification schemes relating to aquaculture operations and fisheries, including the Marine Stewardship Council program, which relates to fisheries internationally.

Sustainability indices for management

While gaining community support is essential, sustainability indexes are also important management tools, because they shed light on the factors that influence stock levels. This understanding, in turn, is crucial to ensure these levels are kept within (or returned to) the sustainable range.

The importance and effectiveness of fisheries management based on sound science was, once again, demonstrated recently when Southern Bluefin Tuna, a formerly overfished and depleted stock, was rated as sustainable. This result comes after decades of careful management to re-build numbers while allowing controlled fishing to support jobs and communities.

Sustainability indices use reference points to determine what stock levels are sustainable in each case. These points are ‘the operational or measurable benchmarks that identify targets to be achieved on average, limits to be avoided and triggers to initiate management responses’ (Sainsbury 2008). Reference points are usually set in relation to fish abundance (biomass), fishing mortality (removals from the population due to fishing) or both.

Best-practice management generally involves setting reference points for both biomass (the total number or weight of fish in the ocean) and fishing mortality (removals by fishing). Estimating stock biomass as well as fishing mortality is important, because biomass varies in response to non-fishing variables (e.g. environmental effects) as well as fishing pressure.

The three main reference points that are commonly used are:

  • Target reference point: the point around which biomass and fishing mortality would ideally fluctuate.
  • Limit reference point: the lowest biomass or highest fishing mortality a stock can withstand without becoming depleted. Management should be such that there is a very low likelihood of breaching a limit reference point. Immediate management intervention is required if a limit reference point is breached.
  • Trigger reference point: typically intermediate between target and limit points, this provides the cue to initiate management responses to declining biomass and/or rising fishing mortality to bring the stock back towards the target reference point.

Reference points should be set according to clearly defined management objectives for a stock (Hilborn 2020). Common management objectives include maximising sustainable food production, maximising economic returns from fishing, or maintaining a stock that is important for broader ecosystem function, such as an important prey species, at a precautionary biomass level (Haddon et al. 2013, Hilborn et al. 2020). While pursuing these objectives, there is the ongoing need to avoid breaching limit reference points.

Limit reference points tend to be set where irreversible (or slowly reversible) recruitment impairment would occur.

Within the Food and Agriculture Organization of the United Nations (FAO) for status reporting framework, a stock is considered to be:

  • ‘overexploited’ if present biomass is found to be <40 percent of unfished biomass  
  • ‘fully exploited’ if present biomass is between 40 and 60 percent of unfished biomass, and  
  • ‘underexploited’ if present biomass is >60 percent of unfished biomass.

Customising reference points

When fisheries managers set reference points, where possible they use species-specific information to account for a stock’s population parameters. These may include characteristics such as how long it lives, how quickly it grows and how quickly it starts to reproduce. There’s a delicate balancing act in management to account for the natural variability of a species over time, fishing activity and responses to other environmental factors.

A species that is short-lived, fast growing and reproduces rapidly might have lower reference points for biomass, allowing greater fishing effort, than a slow growing species that matures later in life and produces fewer offspring.

However, fast-growing, short-lived species typically have large natural variations in their abundance, and excessive fisher pressure that coincides with a period of naturally low abundance or poor recruitment can cause a fishery to collapse (Haddon et al. 2013). So, in some cases, dynamic reference points may work to better reflect current circumstances and adapt to changing ones.

In other cases, a stock’s reproductive potential (e.g. egg production) may be estimated. Some fisheries scientists have argued that measuring egg production would capture changes in fecundity, egg viability, and sex ratio within a stock (Kell et al. 2015). In a different context, the Daily Egg Production Method (DEPM) is generally the most practical method for estimating biomass for small pelagic species (e.g. sardines) (Ward et al. 2018).

The role of a stock within its ecosystem is also an important consideration when setting reference points. Key prey or forage species, for example, may require conservative reference points to maintain ecosystem integrity.


Every two years, the FRDC funds and manages the collation of the Status of Australian Fish Stocks Reports (SAFS). These bring together available biological, catch and effort information to determine the status of Australia’s key wild-catch fish stocks from state, territory and Commonwealth fishery jurisdictions.

SAFS reports are used by a range of stakeholders, including fisheries managers and scientists, consumers, and the seafood industry (including retailers). The reports are available on the SAFS website (, and via a user-friendly app, so consumers can use the findings to inform their purchases.

SAFS statuses represent a composite consideration of biomass and fishing mortality; for example, a ‘sustainable’ status requires evidence that both biomass and fishing mortality are above the limit reference point.

The SAFS framework does not define particular ‘one size fits all’ levels of biomass or fishing mortality as limit reference points. Rather, the limit reference point for biomass is defined as the point at which recruitment (the process by which new generations of young fish join the population) is likely to be impaired. Similarly, the limit reference point for fishing mortality in SAFS is the level of fishing pressure likely to either drive the stock towards the point of recruitment impairment, or prevent its recovery if impairment has already occurred. Teams of authors from each jurisdiction work together to define these points for each stock.

Since July 2018, SAFS summary information has also been used to inform Australia’s progress against UN Sustainable Development Goal 14.4.1 (the proportion of fish stocks within biologically sustainable levels).

The SAFS stock status framework is portrayed diagrammatically below: 

Overview SAFS stock status

More details about SAFS are accessible online at


Kell, L.T., Nash, R.D.M., Dickey-Collas, M., Mosqueira, I., Szuwalski, C. (2015). Is spawning stock biomass a robust proxy for reproductive potential? Fish and Fisheries

Ward, T.M., Carroll, J., Grammer, G.L., James, C., McGarvey, R., Smart, J. & Ivey, A.R. Improving the precision of estimates of egg production and spawning biomass obtained using the Daily Egg Production Method, Fisheries Research and Development Corporation Report 2014-026.



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