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Introducing the Fish Stock Sustainability Index 3.0

February 03, 2020

NOAA Fisheries has made updates to the Fish Stock Sustainability Index (FSSI) used to measure fishery performance.

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The Fish Stock Sustainability Index is a quarterly index that measures the performance of certain fish stocks. To make sure the index continues to focus on the most important commercial and recreational stocks, we’ve revised the list of included stocks.

The index allows for a quick, clear snapshot of the performance of U.S. fishery management. When the status of a commercially or recreationally important stock improves (e.g., no longer subject to overfishing, not overfished, or rebuilt), the total index score increases.

FSSI Graphic of fish stock sustainability
2021 FSSI Graphic of fish stock sustainability

The index tracks a total of 175 fish stocks, down from 199 stocks in the previous version. The stocks in the index—selected for their importance to domestic fisheries—represent more than 80 percent of total U.S. fishing catch.

NOAA Fisheries tracks the status of all international and domestic stocks contained in federal fishery management plans whether or not they meet criteria for inclusion in the index.

When we developed the index in 2005, it included 230 fish stocks and the maximum index score was 920 points. In 2015, we trimmed it to 199 stocks and a maximum score of 1,000.

Determining the Score

Step 1: Assign weighted criteria points for each stock based on the following:

Criteria Criteria Points
1. "Overfished" status is known. 0.5
2. "Overfishing" status is known. 0.5
3. Overfishing is not occurring (for stocks with known "overfishing" status). 1.0
4. Stock biomass is above the "overfished" level defined for the stock. 1.0
5. Stock biomass is at or above 80% of the biomass that produces maximum sustainable yield (BMSY)* 1.0

* Stocks rebuilding from a previously overfished condition are not awarded the fourth point until they reach Biomass Maximum Sustainable Yield, as mandated by the Magnuson-Stevens Act. After they have been fully rebuilt, they may fluctuate within the 80 percent parameter and retain the score of 4 like the other non-rebuilding stocks. This point is in addition to the point awarded for being above the “overfished” level.

Step 2: Calculate the sum of criteria points for all FSSI stocks.

Step 3: Calculate maximum criteria points possible: multiply number of FSSI stocks (175) x maximum criteria points per stock (4 points).

Step 4: Calculate a raw total point score: divide sum of criteria points / maximum criteria points possible.

Step 5: Convert raw total point score to a 1,000 point scale: total raw point score* 1,000.

Read the history of the index and the stocks included in the index since 2005.


Last updated by Office of Sustainable Fisheries on October 20, 2021

Status of Stocks