The Magnuson-Stevens Fishery Conservation and Management Act requires that a fishery management plan specify objective and measurable criteria, or reference points, for determining when a stock is subject to overfishing or overfished. A scientific analysis of the abundance and composition of a fish stock (stock assessment) evaluates the stock against its reference points.
Stock assessments use the best information available, which may include data from fishery landings, scientific surveys, and biological and ecological studies. A stock assessment typically undergoes peer review by independent scientists before it is accepted as the best scientific information available.
Generally, NOAA Fisheries uses the stock assessment and the reference points to determine whether the stock is subject to overfishing or overfished. Information from the stock assessment is used by the regional fishery management council to recommend the annual catch limit for the stock.
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.
Approaching an overfished condition – Expected to be overfished within two years.
Rebuilt – A previously overfished stock has increased in abundance to the target level that supports MSY.
NOAA Fisheries’ stock assessments are key to sustainable fisheries management. A number of NOAA Fisheries resources can help you learn more.
- Learn more about the science behind stock assessments.
- Explore NOAA Fisheries' Office of Science and Technology stock assessment information and resources.
- Methodology for how stocks go from assessment results to a status determination.