NOAA Fisheries' Stock Assessments: The Science of Fisheries

The NOAA Fisheries Service (NMFS) provides high-quality science information on marine fish population abundance and fishery exploitation rates to enable conservation and sustainable management. Stock assessments produce the information necessary to determine a stock’s status relative to pre-determined limits and goals for abundance and exploitation rates. Stock assessments are a data-intensive endeavor and require a range of input data at sufficient levels (including information on catch, abundance trends, and biology) in order to be completed at an adequate level. In the 10 years since NMFS published the Marine Fisheries Stock Assessment Improvement Plan, many improvements to the NMFS stock assessment program and to the stock assessments themselves have been made. Today, 58% of the 230 most important managed fisheries stocks are adequately assessed, an increase over the 43% of major stocks that were adequately assessed in 2001. Additional improvements have been made to commercial and recreational catch monitoring programs, fishery-independent surveys, data collection through development and incorporation of advanced survey sampling technologies, and advancements in population modeling capability. Each of these improvements to the stock assessment enterprise has contributed to improvements in NMFS’ ability to determine stock status and manage stocks sustainably. The demand for additional improvements to stock assessments continues to increase, especially to meet the expectations of the revised National Standard 1 guidelines and annual catch limit implementation. To meet these increasing demands, stock assessments will need to characterize uncertainty more thoroughly in model outputs and move towards supporting risk or tradeoff analyses to determine the probability that a proposed catch limit will prevent overfishing. Additional next steps for improving stock assessments include: improving data quality and assessments for data-poor stocks; developing modeling techniques to support “next generation” assessments that incorporate spatial structure, ecosystem/habitat/environmental process, and multispecies information; and continued improvement of fisheries-independent data collection through the use of advanced technology.