2026 Chesapeake Bay Blue Crab Stock Assessment

This report describes the results of the 2026 Chesapeake Bay Blue Crab Stock Assessment and is organized by the Terms of Reference that were developed by the management agencies and approved by the Chesapeake Bay Stock Assessment Committee.

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Description

Since 2011, blue crabs in the Chesapeake Bay have been monitored annually using estimated abundance and exploitation rates from the Winter Dredge Survey and target and threshold female abundance and exploitation rate reference points from updated runs of the 2011 assessment model. After a new management regime was implemented in 2008 to reduce fishing mortality rates on females, the population showed a strong recovery. However, the post-2008 increase in abundance was short-lived, with abundance and catches declining through the 2010s and 2020s.  Additionally, updates to the 2011 assessment model indicated declining stock productivity with associated changes to biological reference points. Further, additional work with the 2011 assessment model found instability in the estimation of the stock-recruitment parameters that are important components of reference point calculations. The decline in abundance and fishery catch were the primary impetus for conducting this new stock assessment.

This report describes the results of the 2026 Chesapeake Bay Blue Crab Stock Assessment and is organized by the Terms of Reference (TORs) developed by management agencies and approved by the Chesapeake Bay Stock Assessment Committee.

Terms of Reference

  1. Critically review and estimate life history parameters and vital rates of blue crab in the Chesapeake Bay that are relevant to the stock assessment. In particular, the assessment should evaluate the extent and scale of interannual variation in life history parameters and vital rates of blue crab in the Chesapeake Bay.
  2. Describe and quantify patterns in fishery-independent surveys to develop indices of abundance and characterize the size composition of the population. Analyses should include: (1) A comprehensive evaluation of the utility of fishery-independent surveys to inform the stock assessment; (2) Consideration of index standardization which may iv 2026 Chesapeake Bay blue crab stock assessment include effects of environmental and abiotic factors on survey catches; and (3) Characterization of uncertainty in indices of abundance.
  3. Describe and quantify patterns in catch, effort, and CPUE. Analyses should include: (1) Estimation of catch and effort for each jurisdiction; (2) Evaluation of the utility of a commercial CPUE index in the assessment; (3) Examination of the impacts of reporting changes and trends in CPUE; (4) Evaluation and quantification of bycatch and/or discard mortality, and recreational harvest using available data from the jurisdictions; and (5) Characterization of uncertainty in the data.
  4. Evaluate the feasibility of, and if possible, implement blue crab stock assessment models that operate on sub-annual time steps and/or at spatial resolutions lower than that of the entire Chesapeake Bay to better represent population dynamics.
  5. Characterize uncertainty in assessment estimates (mortality and abundance).  
  6. Update the sex-specific catch survey models used in the 2011 benchmark stock assessment with relevant new data. Characterize major changes in assumptions between the 2011 assessment model and the 2023 model.
  7. Based on assessment model results recommend appropriate biological reference points for management. To extent possible, evaluate the appropriateness and utility of (1) Aggregate bay-wide reference points; (2) Sex specific reference points; and (3) Recruitment reference points.
  8. Evaluate stock status relative to recommended reference points.
  9. Identify relevant ecosystem and climate influences (such as habitat, environmental drivers, prey availability, and predation/cannibalism) on the population dynamics and fisheries and, to the extent possible, explore other analyses that support the assessment.
  10. Identify existing data sources and gaps, and, to the extent possible, characterize the uncertainty in the relevant sources of data.
  11. Report on the status of research recommendations from the most recent benchmark assessment. Identify and prioritize research recommendations for future work.

Conclusions 

We addressed all of the TORs for the Chesapeake Bay blue crab stock assessment and developed new approaches for estimating catch and survey indices and a new model for estimating blue crab abundance and fishing mortality rates. Estimates from the new stock assessment indicate that female abundance remained above the levels of concern observed in the early 2000s, but it has been declining since 2010. Male abundance has been relatively low relative to the recommended reference points during the last five years. Fishing mortality rates were above the new reference points in many years before 2010, but after 2010, fishing mortality rates were below the target for females and below the limit for males. The most concerning pattern is the long-term decline in recruitment. While we explored several potential causes of declining recruitment, we did not identify a likely cause. The new reference points and stock assessment approach have improved our understanding of blue crab dynamics in Chesapeake Bay and provide useful information for guiding sustainable management.

Peer Review Reports

These Center for Independent Expert Peer Review reports were produced as part of the Independent Peer Review of the Benchmark Quantitative Fishery Stock Assessment for Blue Crab in the Chesapeake Bay (2023-2025).

Category: Report

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