Rationale and definition:
MSY is the largest average yield (catch) that can theoretically be taken from a species’ stock over an indefinite period under constant environmental conditions. It is usually measured in tons.1 This indicator provides information on the degree of exploitation of fishery resources and the progress towards sustainable management of fisheries. The UN Conference on the Law of the Sea, the UN Fish Stocks Agreement, the Plan of Implementation of the 2001 World Summit on Sustainable Development, and the CBD, among others, all refer to MSY-based reference points and targets.2
In the final declaration from Rio+20, states committed to take urgent measures to “maintain or restore all stocks at least to levels that can produce the maximum sustainable yield (MSY).”
All UN Member states are asked to report their annual landings by fish species or species group to the FAO. Data quality varies from country to country with fishery landings data often reported by national governments in aggregated form rather than by fish species.
Comments and limitations:
One problematic aspect of the MSY is that it is calculated for a single species, ignoring the effects on or from other species. An alternative concept to the MSY is the Optimum Sustainable Yield (OSY) that also takes into account economic, social, and ecological factors such as job creation. The OSY can be either equal to or below the MSY. However, there is no agreement on a common definition of OSY.
Preliminary assessment of current data availability by Friends of the Chair:
Primary data source:
Administrative data from national production and international trade statistics.
Potential lead agency or agencies: