Population Assessments | NOAA Fisheries
Source: https://www.fisheries.noaa.gov/topic/population-assessments
Archived: 2026-04-23 17:19
Population Assessments | NOAA Fisheries
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Population Assessments
Population Assessments
Population assessments are critical for measuring the health and abundance of fish, marine mammals, and endangered and threatened species.
Population assessments are a key component of marine resource management. These assessments allow us to evaluate and report the status of managed fisheries, marine mammals, and endangered/threatened species under the authorities of the
Magnuson-Stevens Act
, the
Marine Mammal Protection Act
, and the
Endangered Species Act
.
To conduct population assessments, our scientists:
Collect data and information
Analyze results through quantitative methods
Hold peer review
Communicate results to our
partners
and stakeholders
The assessment process uses current data and advanced analytical techniques in an effort to provide the best scientific information available for conservation and management decisions.
Featured News
Leadership Message
50 Years of Innovation and Leadership: Celebrating the Magnuson-Stevens Act
Alaska
New England/Mid-Atlantic
Pacific Islands
Southeast
West Coast
National
International
Feature Story
Genetics Shines New Light on Cod Populations and Distributions in Alaska
Alaska
Feature Story
Record 30,000 Endangered Central California Coast Coho Salmon Return to Mendocino Coast Rivers
West Coast
Feature Story
NOAA Conducts First Comprehensive Aerial Survey of Ice Seals in the Arctic
Alaska
View More News
More Information
Research Surveys
Sustainable Seafood
Marine Mammal Protection
Endangered Species Conservation
Laws & Policies
Stock Assessment Improvement Plan
FACT
3 types of data are commonly used in fish stock assessments
Fish stock assessments often use catch, abundance, and biology data. These data feed into mathematical models that produce estimates of the fishery management factors needed for managers to make decisions about how to best regulate a fishery.
FACT
3 scientific review groups advise on marine mammal assessments
Scientific review groups advise NOAA Fisheries and U.S. Fish and Wildlife Service on the status of marine mammal stocks within three areas: Alaska, the Atlantic (including the Gulf of America), and the Pacific.
Show me another fact
Fish Stock Assessments
Stock assessments measure the impact of fishing on fish and shellfish stocks. Assessments also project harvest levels to maximize the number of fish that can be caught every year while preventing overfishing, protecting the marine ecosystem, and—where necessary—rebuilding depleted stocks.
Learn more about fish stock assessments
Marine Mammal Assessments
These reports provide resource managers with information needed to manage marine mammal stocks protected under Marine Mammal Protection Act. These reports contain valuable information about geographic range, population size and trends, productivity rates, and estimates of mortality to design and implement appropriate conservation measures.
Learn more about marine mammal assessments
Endangered Species Assessments
These assessments provide the foundation for evaluating the status of—and threats to—endangered marine mammals, fish, and sea turtles managed by NOAA Fisheries under the Endangered Species Act. Endangered species assessments include synthesis and analysis of scientific information on a species’ or stock’s population structure, life history characteristics, abundance, and threats—particularly those caused by human activities.
Learn more about endangered species assessments
Understanding Population Assessments
Population assessments—also known as stock assessments—provide important information for marine resource management.
Read More
Multimedia
NOAA Fisheries Video Gallery
Podcast
Oceanic Whitetip Sharks: A Plan for Recovery
New England/Mid-Atlantic
Pacific Islands
Southeast
West Coast
National
International
Podcast
A Look at the Vast Waters and Rich Diversity of Marine Life in the U.S. Pacific Islands
Pacific Islands
Video
Sea Turtles: Is the Future Female?
National
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 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 stocks 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:
Data Required to Assess Fish Stocks
Stock Assessment Models
More About Models
Ecosystem Factors
Future of Stock Assessments
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.
Learn more about research surveys
Conducting Stock Assessments
Along with our regional, state, and international partners, we conduct an average of 175 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. A new
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 also has a public version, the
Stock Status, Management, Assessment, and Resource Trends (Stock SMART)
web portal that provides easy access for anyone to view and download summaries and results from stock assessments since 2005.
Regional Stock Assessments
Interested in specific regional stock assessments?
Alaskan/North Pacific Stocks
Pacific Islands Stocks
Pacific Highly Migratory Species
Other Pacific Stocks
Atlantic Highly Migratory Species
Northeast Stocks
Southeast Stocks
Or take a deeper dive and learn more about our stock assessment programs at our science centers:
Alaska Fisheries Science Center | Status of Stocks and Multispecies Assessment Program |
Marine Ecology and Stock Assessment Program
Pacific Islands Fisheries Science Center |
Fisheries Research and Monitoring Division
Northwest Fisheries Science Center |
Population Ecology
|
Mathematical Biology and Systems Monitoring
Southwest Fisheries Science Center |
Stock Assessment Programs
Northeast Fisheries Science Center |
Population Dynamics Branch
Southeast Fisheries Science Center |
Sustainable Fisheries Division
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
resources
and opportunities for continued education and training in the evolving skills necessary for next generation stock assessments through in-person and online workshops.
Population Assessments and Fish Stocks
Fish stock assessments measure demographic information to evaluate the impact of fishing on shellfish and fish populations.
More Information
Fish Assessment Reports
NOAA Fisheries Integrated Toolbox
Research Surveys
Stock SMART
Marine Mammals
We publish
marine mammal stock assessment reports
, which contain information about geographic range, population size and trends, productivity rates, and estimates of mortality. Marine mammals under our jurisdiction include
whales
,
dolphins/porpoises
, and
seals/sea lions
. The reports are prepared in consultation with one or more of three regional
scientific review groups
, and drafts are available for public review and comment.
Each year, we review reports for
strategic stocks
of marine mammals. For non-strategic stocks, we review reports every three years, or when new information becomes available. If the reviews show that the status of the stock has changed or can be assessed more accurately, we revise the report in consultation with the scientific review groups and after public review and comment.
The
U.S. Fish and Wildlife Service
also prepares stock assessment reports for marine mammals under their jurisdiction including manatees, polar bears, sea otters, and walruses. Some reports include information on multiple stocks.
NOAA Fisheries and U.S. Fish and Wildlife Service prepare reports only for marine mammal stocks that occur in waters under U.S. jurisdiction, as stated in the
Marine Mammal Protection Act
. We do not prepare reports for marine mammal stocks worldwide.
Conducting Assessments
Data collection, analysis, and interpretation are conducted through marine mammal research programs at each of our regional fisheries science centers and by other researchers. Data are collected in a variety of methods, including
aerial and ship-based surveys, acoustic monitoring, photo identification studies, biopsy sampling for genetic studies, and tagging
.
The Marine Mammal Protection Act provides only general descriptions of the kinds of information that must be included in stock assessment reports. For example, the reports require a "minimum population estimate," which means we have "reasonable" assurance there are at least the estimated number in the population.
Each marine mammal stock assessment report includes:
A description of the stock's geographic range.
A minimum population estimate
Current population trends.
Current and maximum net productivity rates.
"
Potential biological removal
" levels.
Status of the stock.
Estimates of annual human-caused mortality and serious injury by source.
Descriptions of other factors that may be causing a decline or impeding the recovery of strategic stocks.
How Many Marine Mammal Stock Assessment Reports Are Reviewed or Prepared Annually?
The first stock assessment reports prepared in 1995 included about 165 reports on marine mammal stocks in U.S. waters:
Approximately 60 reports in the Atlantic Ocean and Gulf of America.
Approximately 60 reports along the Pacific Coast of the continental United States and Hawaii.
Roughly 35 reports in Alaska and the North Pacific.
Roughly 10 reports for manatees, polar bears, sea otters, and walrus in U.S. waters (prepared by U.S. Fish and Wildlife Service).
The number of reports may vary from year to year because stock identification is subject to change. Marine mammal stocks may be added or removed from the regional list of compiled reports due to changes in distribution.
Using Assessments for Management and Conservation
We use marine mammal stock assessment reports to:
Identify and evaluate the status of marine mammal populations and the effects of human activities upon them.
Evaluate the population level effects when authorizing the "take" of marine mammals
incidental to human activities
.
Design and conduct appropriate conservation measures.
Classify fisheries on the Marine Mammal Protection Act
List of Fisheries
.
Evaluate the progress of each fishery in reducing its incidental mortality and serious injury to insignificant levels approaching a zero mortality and serious injury rate.
Improving Assessments
For marine mammal stock assessments, the Marine Mammal Protection Act provides only general guidance on assessment methods and on the content of the reports. To include values for the required elements in the reports, NOAA Fisheries and U.S. Fish and Wildlife Service translated qualitative concepts into quantitative terms. After building a scientific foundation through simulation modeling, we proposed guidelines for selecting specific values to include in the reports. The guidelines received review and comments by the public and scientific review groups.
View the
Guidelines for Assessing Marine Mammal Stocks
for information on the background, decisions, and default values that go into developing the stock assessment reports.
Additionally, we work with partners to develop and evaluate analytical products and applications to improve population assessments.
To disseminate results and increase national coordination and collaboration in conducting assessments, we support and organize protected species assessment workshops biennially. Other workshops address specific technical topics and advance various protected species science initiatives with direct relevance to management actions. Similarly, various dedicated working groups encourage dissemination of best practices and latest advances in the field.
Marine Mammals Population Assessments
We publish marine mammal population and stock assessments information—geographic range, population sizes, and more—of species occurring in U.S. waters.
More Information
Draft Stock Assessment Reports
Stock Assessment Reports by Region
Stock Assessment Reports by Species/Stock
Guidelines for Assessing Marine Mammal Stocks
More About Stock Assessments for Marine Mammals
Endangered Species
Population assessments provide the foundation for evaluating the status of and threats to marine mammals, sea turtles, and fish protected under the Endangered Species Act and to plan and implement species recovery and conservation actions.
Marine resource managers require accurate and precise information on a species or stock’s population structure, life history characteristics and vital rates, abundance, and threats (particularly those caused by human activities). This information informs agency decisions related to:
A species’ listing status under the
Endangered Species Act
.
Federal or federally-funded activities that might
impact a species
or its
habitat
.
Acceptable
bycatch
levels.
Scientific research and
incidental take permits
issued to agencies, scientific and academic institutions, and industry.
Information included in endangered species population assessments is vital to how we support and advise state and tribal-managed coastal areas. It also allows us to provide scientific and policy leadership to regional and international bodies such as multi-state marine fishery commissions, U.S. fishery management councils, international fishery management organizations, and the
Convention on International Trade in Endangered Species of Wild Fauna and Flora
.
Improving Assessments
We provide funding support to our agency scientists as well as university, federal, and state partners to improve sea turtle population assessments through a competitive, peer-reviewed process. Funds are awarded based on relevance to management concerns and scientific research priorities.
For assessing acoustic impacts on endangered species, we also provide funding through a competitive, peer-reviewed process to support research conducted by NOAA scientists and partners.
We have established the
National Protected Species Toolbox Initiative
to support the development of analytical products and applications that aim to investigate impacts and consequences of human and environmental disturbance on endangered and threatened marine life and other protected species.
Population Assessments for Endangered Marine Species
Population assessments of endangered species are crucial for evaluating statuses and threats and for implementing recovery and conservation actions.
More Information
Endangered Species Act Status Reviews
Improving the Understanding of the Status of U.S. Protected Marine Species
Endangered Species Conservation
Population Assessments Resources
Find documents, data and maps, research, outreach and education materials, and other resources about population assessments.
Documents
Document
Management Track Assessment Plans
These documents briefly summarize our plans before we implement a scheduled Management Track…
New England/Mid-Atlantic
Document
Accounting for Sampling Bias Reveals a Decline in Abundance of Endangered False Killer Whales in the Main Hawaiian Islands
Peer-reviewed journal article in Endangered Species Research about false killer whale population…
Pacific Islands
Document
Stock Assessment Update of the Bottomfish Management Unit Species of the Commonwealth of the Northern Mariana Islands, 2025
Bottomfish management unit species in CNMI show stable exploitable biomass since the previous 2017…
Pacific Islands
Document
Black Cod Almanac 2025
A yearly brief summarizing research and population assessments for the Alaska region on Black Cod /…
Alaska
More Documents
Population Assessments Resources
Find documents, data and maps, research, outreach and education materials, and other resources about population assessments.
Data & Maps
Data
2025 Economic Status of the Groundfish Fisheries Off Alaska
2025 Stock Assessment and Fishery Evaluation report for groundfish fisheries of Alaska.
Alaska
Data
Ecosystem Status Report 2025 Gulf of Alaska
This assessment summarizes and synthesizes climate, biological, and fishing effects on the shelf…
Alaska
Map
StoryMap: Gulf Fishery-Independent Survey of Habitat and Ecosystem Resources
The G-FISHER program is optimizing our Gulf-wide video survey efforts to better monitor reef fish…
Southeast
Data
2025 Results Of Steller Sea Lion Surveys In Alaska
The Alaska Fisheries Science Center’s Marine Mammal Laboratory conducts annual crewed aircraft and…
Alaska
More Data
More Maps
Population Assessments Resources
Find documents, data and maps, research, outreach and education materials, and other resources about population assessments.
Research
Surveys in the Northeast and Mid-Atlantic
We conduct research and monitoring surveys to better understand the physical, biological, economic, and social components of marine ecosystems found in the Northwest Atlantic Ocean from the Canadian Scotian Shelf to Cape Hatteras, North Carolina.
New England/Mid-Atlantic
Peer-Reviewed Research
Population Size Estimate for North Atlantic Right Whales
Population size estimation of North Atlantic right whales from 1990-2024.
New England/Mid-Atlantic
2025 Alaska Fisheries Science Center Groundfish Seminar Series
2025 Groundfish Seminars held virtually using Webex - Recordings Available.
Alaska
Gulf of Maine Bottom Longline Survey
Our Gulf of Maine Bottom Longline Survey collects data on species that prefer rocky habitats—a habitat not efficiently sampled with trawl gear used in bottom trawl surveys
New England/Mid-Atlantic
More Research
Population Assessments Resources
Find documents, data and maps, research, outreach and education materials, and other resources about population assessments.
Outreach & Education
Outreach Materials
2025 Northern Bering Sea Groundfish and Crab Trawl Survey Highlights
In 2025, NOAA Fisheries’ Alaska Fisheries Science Center conducted two surveys within U.S…
Alaska
Outreach Materials
Cook Inlet Beluga UAS Photogrammetry and Photo-Identification Survey Brief - 2025
Boat-based photo-identification and aerial UAS photogrammetry survey of Cook Inlet beluga whales.
Alaska
Outreach Materials
Cook Inlet Beluga Whale Aerial Abundance Survey Research Brief 2025
Aerial survey of Cook Inlet beluga whales
Alaska
Outreach Materials
Maia Kapur and Grant Adams Seminar Flyer
A flyer for presentation by Maia Kapur and Grant Adams during the 2025 Alaska Fisheries Science…
Alaska
More Outreach Materials
More Educational Materials
Skip to main content
Population Assessments
Population Assessments
Population assessments are critical for measuring the health and abundance of fish, marine mammals, and endangered and threatened species.
Population assessments are a key component of marine resource management. These assessments allow us to evaluate and report the status of managed fisheries, marine mammals, and endangered/threatened species under the authorities of the
Magnuson-Stevens Act
, the
Marine Mammal Protection Act
, and the
Endangered Species Act
.
To conduct population assessments, our scientists:
Collect data and information
Analyze results through quantitative methods
Hold peer review
Communicate results to our
partners
and stakeholders
The assessment process uses current data and advanced analytical techniques in an effort to provide the best scientific information available for conservation and management decisions.
Featured News
Leadership Message
50 Years of Innovation and Leadership: Celebrating the Magnuson-Stevens Act
Alaska
New England/Mid-Atlantic
Pacific Islands
Southeast
West Coast
National
International
Feature Story
Genetics Shines New Light on Cod Populations and Distributions in Alaska
Alaska
Feature Story
Record 30,000 Endangered Central California Coast Coho Salmon Return to Mendocino Coast Rivers
West Coast
Feature Story
NOAA Conducts First Comprehensive Aerial Survey of Ice Seals in the Arctic
Alaska
View More News
More Information
Research Surveys
Sustainable Seafood
Marine Mammal Protection
Endangered Species Conservation
Laws & Policies
Stock Assessment Improvement Plan
FACT
3 types of data are commonly used in fish stock assessments
Fish stock assessments often use catch, abundance, and biology data. These data feed into mathematical models that produce estimates of the fishery management factors needed for managers to make decisions about how to best regulate a fishery.
FACT
3 scientific review groups advise on marine mammal assessments
Scientific review groups advise NOAA Fisheries and U.S. Fish and Wildlife Service on the status of marine mammal stocks within three areas: Alaska, the Atlantic (including the Gulf of America), and the Pacific.
Show me another fact
Fish Stock Assessments
Stock assessments measure the impact of fishing on fish and shellfish stocks. Assessments also project harvest levels to maximize the number of fish that can be caught every year while preventing overfishing, protecting the marine ecosystem, and—where necessary—rebuilding depleted stocks.
Learn more about fish stock assessments
Marine Mammal Assessments
These reports provide resource managers with information needed to manage marine mammal stocks protected under Marine Mammal Protection Act. These reports contain valuable information about geographic range, population size and trends, productivity rates, and estimates of mortality to design and implement appropriate conservation measures.
Learn more about marine mammal assessments
Endangered Species Assessments
These assessments provide the foundation for evaluating the status of—and threats to—endangered marine mammals, fish, and sea turtles managed by NOAA Fisheries under the Endangered Species Act. Endangered species assessments include synthesis and analysis of scientific information on a species’ or stock’s population structure, life history characteristics, abundance, and threats—particularly those caused by human activities.
Learn more about endangered species assessments
Understanding Population Assessments
Population assessments—also known as stock assessments—provide important information for marine resource management.
Read More
Multimedia
NOAA Fisheries Video Gallery
Podcast
Oceanic Whitetip Sharks: A Plan for Recovery
New England/Mid-Atlantic
Pacific Islands
Southeast
West Coast
National
International
Podcast
A Look at the Vast Waters and Rich Diversity of Marine Life in the U.S. Pacific Islands
Pacific Islands
Video
Sea Turtles: Is the Future Female?
National
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 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 stocks 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:
Data Required to Assess Fish Stocks
Stock Assessment Models
More About Models
Ecosystem Factors
Future of Stock Assessments
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.
Learn more about research surveys
Conducting Stock Assessments
Along with our regional, state, and international partners, we conduct an average of 175 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. A new
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 also has a public version, the
Stock Status, Management, Assessment, and Resource Trends (Stock SMART)
web portal that provides easy access for anyone to view and download summaries and results from stock assessments since 2005.
Regional Stock Assessments
Interested in specific regional stock assessments?
Alaskan/North Pacific Stocks
Pacific Islands Stocks
Pacific Highly Migratory Species
Other Pacific Stocks
Atlantic Highly Migratory Species
Northeast Stocks
Southeast Stocks
Or take a deeper dive and learn more about our stock assessment programs at our science centers:
Alaska Fisheries Science Center | Status of Stocks and Multispecies Assessment Program |
Marine Ecology and Stock Assessment Program
Pacific Islands Fisheries Science Center |
Fisheries Research and Monitoring Division
Northwest Fisheries Science Center |
Population Ecology
|
Mathematical Biology and Systems Monitoring
Southwest Fisheries Science Center |
Stock Assessment Programs
Northeast Fisheries Science Center |
Population Dynamics Branch
Southeast Fisheries Science Center |
Sustainable Fisheries Division
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
resources
and opportunities for continued education and training in the evolving skills necessary for next generation stock assessments through in-person and online workshops.
Population Assessments and Fish Stocks
Fish stock assessments measure demographic information to evaluate the impact of fishing on shellfish and fish populations.
More Information
Fish Assessment Reports
NOAA Fisheries Integrated Toolbox
Research Surveys
Stock SMART
Marine Mammals
We publish
marine mammal stock assessment reports
, which contain information about geographic range, population size and trends, productivity rates, and estimates of mortality. Marine mammals under our jurisdiction include
whales
,
dolphins/porpoises
, and
seals/sea lions
. The reports are prepared in consultation with one or more of three regional
scientific review groups
, and drafts are available for public review and comment.
Each year, we review reports for
strategic stocks
of marine mammals. For non-strategic stocks, we review reports every three years, or when new information becomes available. If the reviews show that the status of the stock has changed or can be assessed more accurately, we revise the report in consultation with the scientific review groups and after public review and comment.
The
U.S. Fish and Wildlife Service
also prepares stock assessment reports for marine mammals under their jurisdiction including manatees, polar bears, sea otters, and walruses. Some reports include information on multiple stocks.
NOAA Fisheries and U.S. Fish and Wildlife Service prepare reports only for marine mammal stocks that occur in waters under U.S. jurisdiction, as stated in the
Marine Mammal Protection Act
. We do not prepare reports for marine mammal stocks worldwide.
Conducting Assessments
Data collection, analysis, and interpretation are conducted through marine mammal research programs at each of our regional fisheries science centers and by other researchers. Data are collected in a variety of methods, including
aerial and ship-based surveys, acoustic monitoring, photo identification studies, biopsy sampling for genetic studies, and tagging
.
The Marine Mammal Protection Act provides only general descriptions of the kinds of information that must be included in stock assessment reports. For example, the reports require a "minimum population estimate," which means we have "reasonable" assurance there are at least the estimated number in the population.
Each marine mammal stock assessment report includes:
A description of the stock's geographic range.
A minimum population estimate
Current population trends.
Current and maximum net productivity rates.
"
Potential biological removal
" levels.
Status of the stock.
Estimates of annual human-caused mortality and serious injury by source.
Descriptions of other factors that may be causing a decline or impeding the recovery of strategic stocks.
How Many Marine Mammal Stock Assessment Reports Are Reviewed or Prepared Annually?
The first stock assessment reports prepared in 1995 included about 165 reports on marine mammal stocks in U.S. waters:
Approximately 60 reports in the Atlantic Ocean and Gulf of America.
Approximately 60 reports along the Pacific Coast of the continental United States and Hawaii.
Roughly 35 reports in Alaska and the North Pacific.
Roughly 10 reports for manatees, polar bears, sea otters, and walrus in U.S. waters (prepared by U.S. Fish and Wildlife Service).
The number of reports may vary from year to year because stock identification is subject to change. Marine mammal stocks may be added or removed from the regional list of compiled reports due to changes in distribution.
Using Assessments for Management and Conservation
We use marine mammal stock assessment reports to:
Identify and evaluate the status of marine mammal populations and the effects of human activities upon them.
Evaluate the population level effects when authorizing the "take" of marine mammals
incidental to human activities
.
Design and conduct appropriate conservation measures.
Classify fisheries on the Marine Mammal Protection Act
List of Fisheries
.
Evaluate the progress of each fishery in reducing its incidental mortality and serious injury to insignificant levels approaching a zero mortality and serious injury rate.
Improving Assessments
For marine mammal stock assessments, the Marine Mammal Protection Act provides only general guidance on assessment methods and on the content of the reports. To include values for the required elements in the reports, NOAA Fisheries and U.S. Fish and Wildlife Service translated qualitative concepts into quantitative terms. After building a scientific foundation through simulation modeling, we proposed guidelines for selecting specific values to include in the reports. The guidelines received review and comments by the public and scientific review groups.
View the
Guidelines for Assessing Marine Mammal Stocks
for information on the background, decisions, and default values that go into developing the stock assessment reports.
Additionally, we work with partners to develop and evaluate analytical products and applications to improve population assessments.
To disseminate results and increase national coordination and collaboration in conducting assessments, we support and organize protected species assessment workshops biennially. Other workshops address specific technical topics and advance various protected species science initiatives with direct relevance to management actions. Similarly, various dedicated working groups encourage dissemination of best practices and latest advances in the field.
Marine Mammals Population Assessments
We publish marine mammal population and stock assessments information—geographic range, population sizes, and more—of species occurring in U.S. waters.
More Information
Draft Stock Assessment Reports
Stock Assessment Reports by Region
Stock Assessment Reports by Species/Stock
Guidelines for Assessing Marine Mammal Stocks
More About Stock Assessments for Marine Mammals
Endangered Species
Population assessments provide the foundation for evaluating the status of and threats to marine mammals, sea turtles, and fish protected under the Endangered Species Act and to plan and implement species recovery and conservation actions.
Marine resource managers require accurate and precise information on a species or stock’s population structure, life history characteristics and vital rates, abundance, and threats (particularly those caused by human activities). This information informs agency decisions related to:
A species’ listing status under the
Endangered Species Act
.
Federal or federally-funded activities that might
impact a species
or its
habitat
.
Acceptable
bycatch
levels.
Scientific research and
incidental take permits
issued to agencies, scientific and academic institutions, and industry.
Information included in endangered species population assessments is vital to how we support and advise state and tribal-managed coastal areas. It also allows us to provide scientific and policy leadership to regional and international bodies such as multi-state marine fishery commissions, U.S. fishery management councils, international fishery management organizations, and the
Convention on International Trade in Endangered Species of Wild Fauna and Flora
.
Improving Assessments
We provide funding support to our agency scientists as well as university, federal, and state partners to improve sea turtle population assessments through a competitive, peer-reviewed process. Funds are awarded based on relevance to management concerns and scientific research priorities.
For assessing acoustic impacts on endangered species, we also provide funding through a competitive, peer-reviewed process to support research conducted by NOAA scientists and partners.
We have established the
National Protected Species Toolbox Initiative
to support the development of analytical products and applications that aim to investigate impacts and consequences of human and environmental disturbance on endangered and threatened marine life and other protected species.
Population Assessments for Endangered Marine Species
Population assessments of endangered species are crucial for evaluating statuses and threats and for implementing recovery and conservation actions.
More Information
Endangered Species Act Status Reviews
Improving the Understanding of the Status of U.S. Protected Marine Species
Endangered Species Conservation
Population Assessments Resources
Find documents, data and maps, research, outreach and education materials, and other resources about population assessments.
Documents
Document
Management Track Assessment Plans
These documents briefly summarize our plans before we implement a scheduled Management Track…
New England/Mid-Atlantic
Document
Accounting for Sampling Bias Reveals a Decline in Abundance of Endangered False Killer Whales in the Main Hawaiian Islands
Peer-reviewed journal article in Endangered Species Research about false killer whale population…
Pacific Islands
Document
Stock Assessment Update of the Bottomfish Management Unit Species of the Commonwealth of the Northern Mariana Islands, 2025
Bottomfish management unit species in CNMI show stable exploitable biomass since the previous 2017…
Pacific Islands
Document
Black Cod Almanac 2025
A yearly brief summarizing research and population assessments for the Alaska region on Black Cod /…
Alaska
More Documents
Population Assessments Resources
Find documents, data and maps, research, outreach and education materials, and other resources about population assessments.
Data & Maps
Data
2025 Economic Status of the Groundfish Fisheries Off Alaska
2025 Stock Assessment and Fishery Evaluation report for groundfish fisheries of Alaska.
Alaska
Data
Ecosystem Status Report 2025 Gulf of Alaska
This assessment summarizes and synthesizes climate, biological, and fishing effects on the shelf…
Alaska
Map
StoryMap: Gulf Fishery-Independent Survey of Habitat and Ecosystem Resources
The G-FISHER program is optimizing our Gulf-wide video survey efforts to better monitor reef fish…
Southeast
Data
2025 Results Of Steller Sea Lion Surveys In Alaska
The Alaska Fisheries Science Center’s Marine Mammal Laboratory conducts annual crewed aircraft and…
Alaska
More Data
More Maps
Population Assessments Resources
Find documents, data and maps, research, outreach and education materials, and other resources about population assessments.
Research
Surveys in the Northeast and Mid-Atlantic
We conduct research and monitoring surveys to better understand the physical, biological, economic, and social components of marine ecosystems found in the Northwest Atlantic Ocean from the Canadian Scotian Shelf to Cape Hatteras, North Carolina.
New England/Mid-Atlantic
Peer-Reviewed Research
Population Size Estimate for North Atlantic Right Whales
Population size estimation of North Atlantic right whales from 1990-2024.
New England/Mid-Atlantic
2025 Alaska Fisheries Science Center Groundfish Seminar Series
2025 Groundfish Seminars held virtually using Webex - Recordings Available.
Alaska
Gulf of Maine Bottom Longline Survey
Our Gulf of Maine Bottom Longline Survey collects data on species that prefer rocky habitats—a habitat not efficiently sampled with trawl gear used in bottom trawl surveys
New England/Mid-Atlantic
More Research
Population Assessments Resources
Find documents, data and maps, research, outreach and education materials, and other resources about population assessments.
Outreach & Education
Outreach Materials
2025 Northern Bering Sea Groundfish and Crab Trawl Survey Highlights
In 2025, NOAA Fisheries’ Alaska Fisheries Science Center conducted two surveys within U.S…
Alaska
Outreach Materials
Cook Inlet Beluga UAS Photogrammetry and Photo-Identification Survey Brief - 2025
Boat-based photo-identification and aerial UAS photogrammetry survey of Cook Inlet beluga whales.
Alaska
Outreach Materials
Cook Inlet Beluga Whale Aerial Abundance Survey Research Brief 2025
Aerial survey of Cook Inlet beluga whales
Alaska
Outreach Materials
Maia Kapur and Grant Adams Seminar Flyer
A flyer for presentation by Maia Kapur and Grant Adams during the 2025 Alaska Fisheries Science…
Alaska
More Outreach Materials
More Educational Materials