NOAA Fisheries measures the sustainability of the Nation’s fisheries through the Fish Stock Sustainability Index (FSSI). The FSSI tracks the status of rebuilding and maintaining 230 commercially and recreationally important stocks and complexes. The index incorporates critical components of managing fisheries - controlling harvest rates, maintaining population size, and increasing knowledge about the status of fish stocks and complexes.
The FSSI is calculated by assigning a score for each fish stock or complex based on the five criteria below. A fish stock or complex “earns” points when we know its status and when that status is at or above a certain level deemed optimal for the stock. The score increases as additional assessments are conducted, overfishing is ended, and stocks rebuild to the level that provides maximum sustainable yield for the fishery (BMSY, the largest amount of catch the resource can sustain). The FSSI has improved by over 60% since 2000 and quarterly updates are provided. More information on the FSSI is available online.
Overfishing & Overfished OVERFISHINGRefers to the rate of fishing. Overfishing occurs when the rate of removal from a stock is too high, i.e. more fish are being taken from the stock such that the remaining stock can't self-replenish. A priority for the U.S. is ending overfishing so that all stocks have continuous self-sustaining populations.
OVERFISHEDRefers to a population stock that is too low to replenish itself and requires a change in management practices to rebuild. In the U.S., overfished stocks are required to be managed under rebuidling plans that, over time, will return the stock to a prescribed threshold.
FSSI scoring table| SCORING RULES | SCORE |
|---|---|
| 1. Stock has known status determinations: | - |
| -Overfishing status known | 0.5 |
| -Overfished status known | 0.5 |
| 2. Fishing rate is below the overfishing level determined for the stock (i.e. no overfishing) | 1.0 |
| 3. Stock abundance (biomass) is above the minimum stock size threshold defined for the stock (i.e. not overfished) | 1.0 |
| 4. Biomass is at or above 80% of maximum sustainable yield (BMSY) -this point is in addition to the point awarded for being above the overfished level | 1.0 |
| Total Possible | 4.0 |
FSSI Scores on FishChoice
|
Symbol |
Seafood Score |
Overfished |
Overfishing |
Score Summary |
 |
0 OUT OF 4 | Unknown |
Unknown | Neither overfishing nor overfished status is known |
 |
0.5 OUT OF 4 | Known and occuring, and overfishing is unknown* |
Known and occuring, and overfished is unknown* |
*Only one status is known and occurring; either stock is overfished or overfishing is occuring |
 |
1 OUT OF 4 | Known and occuring | Known and occuring | Stock is overfished and overfishing is occurring |
 |
1.5 OUT OF 4 | Known and not occuring, and overfishing is unknown* | Known and not occuring, and overfished is unknown* | *Only one status is known and not occurring; stock is either not overfished or no overfishing is occurring |
 |
2 OUT OF 4 | Known and not occuring if overfishing is occuring | Known and not occuring if overfished is occuring | Both statuses are known and either stock is not overfished or overfishing is not occuring |
 |
2.5 OUT OF 4 | Known and not occuring | Unknown | Stock is not overfished, biomass is at or above 80% BMSY but overfishing status is not known |
 |
3 OUT OF 4 | Known and may or may not be occuring* | Known and may or may not be occuring* | *Both statuses are known; either overfishing is occurring and stock is not overfished and biomass is above 80% BMSY or overfishing is not occurring and stock is not overfished but biomass is not above 80% BMSY |
 |
4 OUT OF 4 | Known and not occuring | Known and not occuring | Stock is not overfished, overfishing is not occurring and biomass is at or above 80% BMSY |