The collapse of cod, flounder, and haddock fish stocks in the Northeast United States has caused widespread concern among managers and fishers in the United States and Canada. The diminishing stocks have forced managers to take strict regulatory measures. Numerous questions have been raised about the adequacy of stock assessment science used to evaluate the status of these stocks and the appropriateness of the management measures taken. Based on these concerns, Congress mandated that a scientific review of the methodology and data used to evaluate these stocks be conducted. In this volume, the committee concludes that although there are improvements to be made in data collection, modeling uncertainty, and communicating between fishers, managers, and scientists, the scientific methods used in the Northeast stock assessments are sound. Recommendations are made on how the stock assessment process can be improved.
- Review of Northeast Fishery Stock Assessments
- Copyright
- Contents
- EXECUTIVE SUMMARY
- ADEQUACY OF SCIENTIFIC INFORMATION FOR MANAGEMENT
- JUSTIFICATION FOR MANAGEMENT ACTIONS
- EFFECTS OF MANAGEMENT REGULATIONS
- SUFFICIENCY OF SURVEY AND LANDINGS DATA
- USEFULNESS OF STOCK ASSESSMENTS AS PREDICTIVE TOOLS
- ALTERNATIVE METHODS TO REGULATE CATCH
- FACTORS AFFECTING ABUNDANCE OF STOCKS
- OTHER CAUSES OF STOCK FLUCTUATIONS
- RECOMMENDED ACTIONS
- 1 INTRODUCTION
- GROUNDFISH RESOURCES OF THE NORTHWESTERN ATLANTIC
- HISTORICAL EXPLOITATION AND ASSESSMENT
- MODERN EXPLOITATION AND ASSESSMENT
- DESCRIPTION OF 1997 U.S. STOCK ASSESSMENT FOR COD, HADDOCK, AND YELLOWTAIL FLOUNDER
- Terms of Reference
- United States and Canadian Stock Assessment Process
- Stock Assessment Procedure and Timing in 1997
- Dealer and Vessel Data
- Trawl Surveys
- Age Sampling
- Models Used
- Results
- HISTORY AND PURPOSE OF THIS STUDY
- 2 GENERAL REVIEW OF NORTHEAST GROUNDFISH STOCK ASSESSMENTS
- INVESTIGATION OF NORTHEAST FISHERY STOCK ASSESSMENTS
- Replication of Assessment Results
- Evaluating Consequences of Alternative Management Actions
- COMPARISON WITH ASSESSMENTS AROUND THE WORLD
- Input Data
- Method and Calibration
- Analyses Included in the Assessment
- Provision of Advice
- Methods for Regional Stock Assessment
- U.S. Northeast Coast
- Canadian Maritimes
- U.S. West Coast
- Assessments and Management of Fish Stocks by International Council for the Exploration of the Sea (ICES)
- Assessments and Management of Whale Stocks by the International Whaling Commission (IWC)
- Precautionary Management Advice
- Summary
- GENERAL EVALUATION OF NORTHEAST GROUNDFISH STOCK ASSESSMENTS BASED ON RECOMMENDATIONS FROM IMPROVING FISH STOCK ASSESSMENTS
- STATUS OF THE FIVE STOCKS
- Gulf of Maine Cod (NEFSC, 1997a; pp. 51-107)
- Stock Size and Condition
- Recent Exploitation Rates
- Have Current Regulations Reduced Fishing Mortality (F)?
- Will Yield-Per-Recruit Change with Lower Fishing Mortality (F)?
- Will Recruitment Increase with Increasing Spawning Biomass or Decline with Recent High Fishing Mortality (F)s?
- Alternative Projections for Gulf of Maine Cod
- Georges Bank Cod (NEFSC, 1997a; pp. 108-170)
- Stock Size and Condition
- Recent Exploitation Rates
- Have Current Regulations Reduced Fishing Mortality (F)?
- Will Yield-Per-Recruit Change with Lower Fishing Mortality?
- Will Recruitment Increase with Increasing Spawning Biomass or Decline with Current Fishing Mortality (F)?
- Georges Bank Haddock (NEFSC, 1997a; pp. 171-223)
- Stock Size and Condition
- Recent Exploitation Rates
- Have Current Regulations Reduced Fishing Mortality (F)?
- Will Yield-Per-Recruit Improve with Lower Fishing Mortality (F)?
- Will Recruitment Increase with Increasing Spawning Biomass or Decline with Recent High Fishing Mortality (F)?
- Georges Bank Yellowtail Flounder (NEFSC, 1997a; pp. 224-259)
- Stock Size and Condition
- Recent Exploitation Rates
- Have Current Regulations Reduced Fishing Mortality (F)?
- Will Yield-Per-Recruit Improve with Lower Fishing Mortality (F)?
- Will Recruitment Increase with Increasing Spawning Biomass or Decline with Current Fishing Mortality ...
- Southern New England Yellowtail Flounder (NEFSC, 1997a; pp. 260-290)
- Stock Size and Condition
- Mid-1990s Exploitation Rates
- Have Current Regulations Reduced Fishing Mortality (F)?
- Will Yield-Per-Recruit Improve with Lower Fishing Mortality (F)?
- Will Recruitment Increase with Increasing Spawning Biomass or Decline with Current Fishing Mortality ...
- 3 REVIEW OF DETAILS OF NORTHEAST GROUNDFISH STOCK ASSESSMENTS
- DATA
- Dealer and Vessel Data
- Observer Program
- Disaggregated Catch Per Unit Effort
- Handling Zeros When Estimating Door Conversion Factors and Other Data
- Survey Coverage
- Age Sampling
- Recreational Sampling
- Environmental/Ecosystem Data
- ASSESSMENT MODELS
- Initial Evaluation of Input Data
- Approaches to Assessment Modeling
- Current Model Assumptions
- Alternative Model Assumptions
- Further Extensions in Time
- Natural Mortality
- Model Verification
- 4 SCIENCE AND MANAGEMENT
- ROLE OF STOCK ASSESSMENT IN THE FISHERY MANAGEMENT PROCESS
- Uncertainty in Stock Assessments
- Timely Use of Stock Assessment Information
- STRATEGIC THINKING AND PROCESS
- PUBLIC HEARING
- Committee Comments on the Public Hearing
- 5 CONCLUSIONS
- RECOMMENDED ACTIONS
- CENTRAL ISSUES
- Adequacy of Scientific Information for Management
- Justification For Management Actions
- Effects of Management Regulations
- Sufficiency of Survey and Landings Data
- Usefulness of Stock Assessments as Predictive Tools
- Alternative Methods To Regulate Catch
- Factors Affecting Abundance of Stocks
- Other Causes of Stock Fluctuations
- STOCK ASSESSMENT AND FISHERY MANAGEMENT
- REFERENCES
- APPENDIXES
- Appendix A Mandate from Magnuson-Stevens Fishery Conservation and Management Act
- Appendix B Committee Biographies
- Appendix C Materials Received from National Marine Fisheries Service (NMFS)
- Appendix D Presentation to the Committee by NMFS Scientists (9 July, 1997, Bedford, Massachusetts)
- Agenda
- Information Presented
- Georges Bank Haddock Research Recommendations
- Georges Bank Yellowtail Flounder Research Recommendations
- Stock Status Summary
- Sarc 24 Advisory Overview
- Probability SSB = Threshold by 2004 Based on Two Sets of Projections
- Appendix E Glossary
- Appendix F Extending Data Series and Alternative Projection Results for Gulf of Maine Cod
- Extending Data Series Back In Time
- Alternative Projections
- Other input data for the projections
- Output and Initial Projections
- Gulf of Maine Cod
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