Each winter since 1988, Chesapeake Biological Laboratory has worked with the Maryland Department of Natural Resources and the Virginia Institute of Marine Sciences to conduct a dredge survey that estimates the total number of blue crabs in the Chesapeake Bay.
From December to March each year, the team drags a 6-foot-wide net — a crab dredge — along the bottom of the Bay at 1,500 locations to collect blue crabs. Scientists record each crab’s size, age, and gender. The team uses the average number of crabs they find in each area to estimate the Bay’s total blue crab population, and from this number they can calculate the number of crabs that watermen can safely harvest in the coming year.
In 2008, laws were passed in Maryland and Virginia to protect the crab population by restricting the number of female crabs watermen could harvest. It worked — the female population nearly tripled from 2008-2010. But in 2011, crab numbers began to fall. The 2014 survey found that the Bay’s blue crab population continues to be low overall, with very few females. Researchers are still trying to understand why, as well as what can be done.
A low blue crab harvest, whether due to a low population or strict regulations, can cause watermen to lose money and consumer prices to increase. Some watermen make up for lost income by overfishing other populations, such as oysters and striped bass.
Dr. Tom Miller, Chesapeake Biological Laboratory director and professor, believes the solution must go beyond fishing limitations and will require examining the Bay’s ecosystem and its ability to support a healthier and higher blue crab population.
Continued blue crab monitoring and management will be critical to sustaining the populations of these iconic Chesapeake species.
