Blue Crab Population Drivers and Stock Assessment in Chesapeake Bay

Description

The Chesapeake Bay blue crab population has experienced significant recent declines in abundance and recruitment. The total abundance of blue crabs estimated in the Bay, based on the 2022 Winter Dredge Survey (WDS), was 227 million—the lowest estimate since the survey began in 1990. Although the blue crab population tends to exhibit natural fluctuations from year to year, the recent continued declines have caused concerns about the effects of changing environmental conditions on blue crab population dynamics and the suitability of the current stock assessment model. The Chesapeake Bay Stock Assessment Committee (CBSAC), the blue crab technical workgroup within the Chesapeake Bay Program, hosted a workshop that brought together blue crab and other scientific experts to discuss Chesapeake Bay blue crab population dynamics and stock assessment to inform an upcoming benchmark stock assessment and analysis of population drivers. The workshop objectives were to: 

1. Identify and discuss potential mechanisms, data needs and available sources, and analytical methods to better understand drivers of blue crab population dynamics in the Bay; and
2. Discuss the assumptions for the current blue crab stock assessment model and evaluate other options that could be incorporated into a benchmark stock assessment.

Workshop discussions identified priority research needs and data gaps that are essential for improving our understanding of blue crab population drivers and stock assessment modeling. Based on the workshop discussions, CBSAC has advised that the focus of the new benchmark stock assessment should be the incorporation of a shorter time-step rather than an annual time-step. Other important parameters could also be reevaluated in the benchmark stock assessment using existing data. To address potentially important factors that influence blue crab population dynamics, CBSAC is interested in developing a Chesapeake Bay ecosystem status report or ecological risk assessment (ERA) in addition to the benchmark stock assessment.