Country Data | National Oceanic and Atmospheric Administration/National Marine Fisheries Service/Species Information System. 2017. Time series values (2005-2016) produced according to methodology described in Metadata document at https://sdg.data.gov/14-4-1/ | The Fish Stock Sustainability Index (FSSI) measures the performance of the most important federally-managed stocks that represent 85% of total U.S. catch.