Scientists observe Cape Morgan

Population Assessments

Fish Stocks

Stock assessments are the scientific foundation of successful and sustainable fishery harvest management. Stock assessments measure the impact of fishing on fish and shellfish stocks. They project harvest levels that maximize the number of fish that can be caught every year while preventing overfishing (removing too many fish), protecting the marine ecosystem, and—where necessary—rebuilding overfished (depleted) stocks.

Each stock assessment produces a report that provides fishery managers with a scientific basis for setting sustainable harvest policies under the authority of the Magnuson-Stevens Fishery Conservation and Management Act. Under the Act, we partner with eight regional fishery management councils to manage nearly 500 fishery stocks. NOAA Fisheries provides scientific guidance to resource managers by addressing fundamental questions including:

  • What target harvest rate (percent removal per year) best balances resource conservation and use?
  • Has a stock declined into an overfished condition?
  • Does a stock’s recent harvest rate exceed sustainable levels (i.e., is overfishing occurring)?

Stock assessments also support ecosystem-based fisheries management via integrated ecosystem assessments

Stock Assessments 101

To learn more about the basics of the fisheries stock assessment process, read our Stock Assessments 101 series:


    Collecting Data 

    In addition to commercial and recreational fishery-dependent data sources, many stock assessments use fishery-independent data from surveys. We conduct sample surveys for fishes, invertebrates, and environmental conditions (e.g., temperature, salinity, dissolved oxygen) across the eight regions of the United States exclusive economic zone. We analyze abundance and biological data (e.g., species, length, stomach content) collected by these surveys in stock assessments. x

    Fisheries-Independent Survey System

    Fishery-independent surveys are managed by our regional fisheries science centers and tracked nationally via the Fisheries-Independent Survey System. This national system characterizes our ocean observation activities and data collection during fishery-independent surveys and provides up-to-date information to fishery scientists, managers, and the public through flexible digital mapping and tabular reporting applications.

    Learn more about the Fisheries-Independent Survey System 

    Conducting Stock Assessments

    Along with our regional, state, and international partners, we conduct an average of 200 stock assessments annually. This includes more than 85 assessments of stocks included in the Fish Stock Sustainability Index, which is used to measure the performance of the most commercially and recreationally important fisheries.

    We collect and store fish stock assessment results and related information in the Species Information System. This public portal allows users to view and download stock assessment summaries and results. We also produce National Fish Assessment reports on a quarterly basis with up-to-date summaries on the status of NOAA Fisheries assessment activities for federally-managed fish stocks. 

    Stock Assessment Prioritization

    We provide the scientific information that supports the management of approximately 500 fish stocks. However, we only have data and resources to assess about 200 stocks each year. Stock assessment prioritization allows us to work with regional partners to decide which stocks are assessed each year.

    Stock assessment prioritization considers stocks managed under federal fishery management plans as well as non-federal stocks that might also be assessed by our regional fisheries science centers. This process considers:

    • First-time assessments for previously unassessed stocks.

    • Updating existing assessments using established methods and data types.

    • Upgrading assessments to use new types of data and methods.

    We developed the prioritization process during several years of collaboration with partners. The result is a national framework for prioritizing stocks. Each region uses this framework to help determine assessment targets and priorities to best meet those targets.

    Species Information System

    The Species Information System database is the central repository for regional and national fish stock information across NOAA Fisheries and includes stock assessment results and related information used to determine stock status. The database includes a species information public portal that provides easy access for anyone to view and download summaries and results of the most recent stock assessments.

      Regional Stock Assessments

      Interested in specific regional stock assessments?

      Or take a deeper dive and learn more about our stock assessment programs at our science centers:

      Improving Stock Assessments

      We are working to advance our stock assessment program to provide fishery managers and the public with more timely, accurate, and complete information on sustainable catch levels and fish stock status. We are updating our Stock Assessment Improvement Plan, first published in 2001, which provides a framework for moving toward a next generation stock assessment enterprise.

      The vision of this “next generation” enterprise is to improve timeliness and efficiency of assessments while maintaining their utility to fishery management, prioritizing work relative to available resources, expanding the scope of stock assessments to be more holistic and ecosystem-linked, and using innovative modeling and data collection techniques. When finalized, the updated Stock Assessment Improvement Plan will better guide us toward our vision of resilient ecosystems, communities, and economies for future generations.
      View our Stock Assessment Improvement Plan

      Stock Assessment Training 

      We also support the development of future and current stock assessment scientists. Programs focused on training the next generation of scientists in stock assessment and other relevant career fields include the QUEST Program and NOAA Fisheries-Sea Grant Fellowship Program. We also provide current stock assessment scientists with opportunities for continued education and training in the evolving skills necessary for next generation stock assessments through in-person and online workshops.