About one-third of assessed marine fish stocks were overfished in 2021: the United Nations’ presentation of FAO’s indicator puts the share at 35.5%. FAO’s 2024 report gives a closely related estimate of 37.7%. These figures describe assessed marine stocks—not every fish population worldwide—and they count stocks rather than the amount of fish caught.
What does “overfished” mean?
FAO defines an overfished stock as one whose abundance has fallen below the level capable of producing maximum sustainable yield (MSY). In other words, the measure concerns the condition of a fish stock, not simply whether fishing is taking place or how many fish are caught in a particular year. FAO describes it as “stock abundance fished to below the level that can produce maximum sustainable yield (MSY)” in its State of World Fisheries and Aquaculture 2024.
“Biologically unsustainable” is the corresponding category in the global statistics. It does not mean that every fish in a stock has disappeared; it means abundance is below the MSY-based threshold.
Why are there two global percentages?
The two prominent figures refer to closely related FAO reporting series, but their stock coverage and methodology differ. They both use 2021 data, so the difference is not evidence of a sudden change between years.
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| Measure | Share classified as sustainable | Share classified as unsustainable | What it covers |
|---|---|---|---|
| UN presentation of FAO SDG indicator 14.4.1, reported in 2025 | 64.5% | 35.5% | Assessed marine fish stocks; indicator value for 2021 |
| FAO SOFIA 2024 monitored-stock series | 62.3% | 37.7% | 445 aggregated stocks representing approximately 72% of global marine fisheries production; 2021 status |
For a concise answer, “roughly one-third of assessed marine stocks” is more robust than presenting either percentage as a census of all fish populations. The denominator is assessed marine stocks, and the two series do not have identical coverage.
Does that mean one-third of the fish caught come from overfished stocks?
No. The headline percentages count stocks, giving each assessed stock equal weight. A separate FAO production-weighted estimate says approximately 77.2% of 2021 fishery landings came from biologically sustainable stocks. The remaining landings therefore came from stocks classified as biologically unsustainable under that measure.
The catch-weighted result can look more favorable because a large, productive fishery counts more in the landings calculation than a small stock, while both count as one stock in the stock-based percentage. The two measures answer different questions: how many assessed stocks are unsustainable, and what share of landings comes from sustainable stocks.
Is overfishing getting worse?
The long-term global indicator shows a decline in the sustainable share: it was 90% in 1974 and 64.5% in 2021. That trend indicates that a smaller proportion of assessed stocks met the biological sustainability standard by 2021. It does not, by itself, describe every fish population or show that every fishery followed the same path.
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How do national figures compare?
National statistics can illustrate stock status in one country, but they should not be substituted for the global FAO estimate. For example, NOAA’s U.S. Status of Stocks 2024 lists 23 stocks subject to overfishing and 42 stocks that were overfished at the end of 2024. These are distinct categories: “subject to overfishing” concerns the rate of fishing, while “overfished” describes depleted stock abundance. The U.S. figures cover NOAA’s stock lists, not all global marine stocks.
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What to keep in mind when comparing figures
- Stock status: Check whether the statistic means abundance below the MSY threshold or fishing pressure that is currently too high.
- Counting method: A stock-count share and a catch- or production-weighted share are not interchangeable.
- Time period: Confirm the year represented by the data, which may differ from the report’s publication year.
- Coverage: Global estimates draw on assessed and aggregated stocks, not a complete census of every fish population.
- Management and assessments: Regional results vary with both management effectiveness and which stocks are assessed, so a comparison needs to consider both.
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