NOAA Fisheries’ scientific stock assessments are critical to effective fisheries management. Using data gathered from commercial and recreational fishermen and our own on-the-water scientific observations, a stock assessment describes the past and current status of a fish population or stock, answers questions about the size of the stock, and helps predict how a fishery will respond to current and future management measures.

Based on the results of stock assessments, NOAA Fisheries routinely updates the status of fish stocks managed under federal fishery management plans. Stock status determinations include:

• Subject to overfishing—a stock with a fishing mortality (harvest) rate that is higher than the rate that produces maximum sustainable yield (MSY)—the largest long-term average catch that can be taken from a stock under prevailing environmental and fishery conditions.
• Overfished—a stock with a biomass level depleted to a degree that the stock’s capacity to produce MSY is jeopardized.
• Rebuilt—a previously overfished stock that has increased in abundance to the target level that supports MSY.

These stock status determinations, in conjunction with results of the stock assessments, are used by the regional fishery management councils to recommend annual catch limits and other management measures for individual fish stocks.

NOAA Fisheries releases an annual Status of U.S. Fisheries report that outlines the progress we’re making to end and prevent overfishing and to rebuild fish stocks.

Stock status determinations also help NOAA Fisheries calculate the Fish Stock Sustainability Index (FSSI), which measures the performance of important U.S. fish stocks. First implemented in 2005, the FSSI is a quarterly index that includes 199 fish stocks selected because of their importance to commercial and recreational fisheries. The FSSI measures the performance of these fish stocks, which represent 85 percent of total U.S. catch. Since 2000, increases in the FSSI show significant progress in sustainably managing U.S. fisheries.

To continue the sustainable management of U.S. fisheries, NOAA Fisheries consistently works to ensure science-based determinations of stock status and better linkages to biological, socioeconomic, and ecosystem conditions. We strive to conduct research to reduce bycatch and better understand ecosystem and habitat factors and the effects of climate change on fisheries.