About one third of the world's assessed marine fish stocks are fished at biologically unsustainable levels.

Is it true that about one third of the world's assessed marine fish stocks are fished at biologically unsustainable levels?

Yes. Our World in Data reports that one-third (34%) of assessed global fish stocks were overfished in 2017, and the FAO's 2025 review classifies 35.5 percent of stocks as overfished, both matching the claim's figure of about one third. A European regional indicator and a Northwest Mexico study give local unsustainability rates that are consistent in direction but narrower in scope.

Verdict: SUPPORTED · 4 sources for, 0 against · Last checked 3 Oct 2026

The private library was unavailable for some searches in this check. Missing library results are not evidence against the claim.

Status of marine fish and shellfish stocks in Europe's seas | Indicators | European Environment Agency (EEA). (n.d.). eea.europa.eu. https://www.eea.europa.eu/en/analysis/indicators/status-of-marine-fish-and

Fish and Overfishing | Our World in Data. (n.d.). ourworldindata.org. https://ourworldindata.org/fish-and-overfishing

FAO releases the most detailed global assessment of marine fish stocks to date. (n.d.). fao.org. https://www.fao.org/newsroom/detail/fao-releases-the-most-detailed-global-assessment-of-marine-fish-stocks-to-date/en

V, J., G, R., F, A., & F, A. (2026). Assessing the sustainability of reef and demersal fish stocks in Northwest México under a data-limited approach.. doi.org. https://doi.org/10.7717/peerj.21404