Testing Blue Crab Management: Simulating the Present to Sustain the Future

Description

The first scientific assessment of management goals for the Chesapeake Bay blue crab fishery was completed in 1997. Subsequent benchmark assessments occurred in 2005 and 2011, and this final benchmark assessment has been regularly updated with new data. However, the performance of these assessments has never been evaluated.

Evaluating the performance of assessments is an essential element of modern fisheries management. Most often, this is achieved by using an operating model approach. This approach involves developing a population model of blue crab. The population model, also called the operating model, projects the patterns within a blue crab population when its dynamics are specified. Simply stated, we know the “true” values all of the key parameters in this model, including abundance, catch, as well as the rates of fishing and natural mortality. We then take statistical samples from this model, in much the same way as we take samples from the real blue crab population in the Bay. Next, we input the samples into the assessment model to estimate the population parameters. Comparing the population parameters estimated from the assessment model to the “true” values from the operating model allows us to assess the accuracy and precision of population parameters derived from the assessment model.

This document summarizes a study that used the operating model approach to test the performance of blue crab benchmark assessments and management.