Winter Dredge Survey
The Bay-wide Blue Crab Winter Dredge Survey (WSD) is an annual cooperative effort between the Virginia Institute of Marine Science (VIMS) and the Fisheries Service of the Maryland Department of Natural Resources (DNR).
The survey, in operation since 1990, allows researchers to
- Accurately gauge the total population of blue crabs in Chesapeake Bay
- Identify year-to-year trends in blue crab abundance
- Characterize the size and sex of individual crabs
- Estimate over-wintering mortality,
- Understand seasonal migration patterns, and
- Assess the effects of the crab harvest
The winter dredge survey is the most comprehensive and statistically sound of the blue-crab surveys conducted in the Bay. Resource managers rely on its findings, along with data on annual fishery removals, to guide their on-going management of Chesapeake Bay’s blue crab stock.
Survey results show that there has been a persistent and substantial decline in the spawning stock, recruitment, larval abundance, and female size of blue crabs in Chesapeake Bay between 1992 and present.
Management actions, including a blue crab spawning sanctuary and harvest restrictions, are now in place to help the Bay’s blue crab population rebound to a healthy, sustainable level.
Results from the most recent (2008-2009) Winter Blue Crab Dredge Survey show that the Chesapeake Bay’s adult population of blue crabs has increased substantially compared to the previous year, indicating that management measures put into place in 2008 to address population declines are beginning to work.
