Maximum Sustainable Yield: a ClientEarth guide

The document defines Maximum Sustainable Yield (MSY) as the highest amount of fish that can be harvested from a stock indefinitely without causing depletion. It details the biological reference points used to estimate MSY—BMSY, SSBMSY, and FMSY—and emphasizes the necessity of a 'precautionary approach' to account for environmental uncertainties and data gaps. The guide notes that 57% of Europe's fish stocks are currently overfished and highlights legal and international commitments to reach MSY by 2015 (where possible) and 2020 for all stocks under the Marine Strategy Framework Directive.

• Maximum Sustainable Yield (MSY) is defined as the peak growth rate of a fish stock, representing the maximum amount of fish that can be harvested indefinitely provided the harvest does not exceed the surplus generated by reproduction.
• Fisheries managers use three primary biological reference points to estimate MSY: BMSY (the biomass level where a stock is capable of producing MSY), SSBMSY (the biomass of mature, reproducing fish at MSY), and FMSY (the fishing mortality level that maintains a stock at MSY).
• A 'precautionary approach' is required to manage uncertainties in stock assessments and environmental changes, meaning stocks should be kept above MSY levels and fishing should remain below the maximal MSY level. This approach is legally mandated by UNCLOS and the Treaty on the Functioning of the European Union.
• As of 2012, 57% of Europe's fish stocks are classified as overfished (below MSY). While there are international commitments to reach MSY by 2015, 54% of stocks—including most in the Mediterranean—lack the data necessary for immediate assessment.
• The Marine Strategy Framework Directive is a European law that mandates the achievement of MSY for all fish stocks by 2020.

APA

ClientEarth (2012). Maximum Sustainable Yield: a ClientEarth guide. https://www.clientearth.org/latest/news/maximum-sustainable-yield-a-clientearth-guide/

Chicago

ClientEarth. Maximum Sustainable Yield: a ClientEarth guide. 2012. https://www.clientearth.org/latest/news/maximum-sustainable-yield-a-clientearth-guide/.

Wikipedia

{{cite report |author=ClientEarth |title=Maximum Sustainable Yield: a ClientEarth guide |date=28 September 2012 |url=https://www.clientearth.org/latest/news/maximum-sustainable-yield-a-clientearth-guide/ |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{clientearth2012maximum, author = {{ClientEarth}}, title = {{Maximum Sustainable Yield: a ClientEarth guide}}, institution = {ClientEarth}, year = {2012}, month = sep, url = {https://www.clientearth.org/latest/news/maximum-sustainable-yield-a-clientearth-guide/}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }