There is nothing more “Chesapeake” than the blue crab. The Bay’s signature crustacean is one of the most recognizable critters in the watershed, and supports commercial and recreational fisheries. But blue crabs are vulnerable to pollution, habitat loss and harvest pressure, and their abundance has fluctuated over time. Water quality improvements, underwater grass restoration and proper harvest management will help maintain this valuable resource into the future.
As both predator and prey, blue crabs are a keystone species in the Chesapeake Bay food web. Blue crabs also support the most productive commercial and recreational fisheries in the Bay.
Blue crabs are both predators and prey in the Bay’s food web.
Over the past 60 years, blue crabs have dominated Chesapeake Bay fisheries.
Each year, scientists use the winter dredge survey to measure the Chesapeake Bay’s blue crab population. Maryland and Virginia scientists visit 1,500 sites over the course of three and a half months, using metal dredges to pull up and count crabs over-wintering in the mud. According to the results of the 2014 survey, 297 million blue crabs are estimated to be living in the Bay.
The Chesapeake Bay Program tracks the abundance of adult female blue crabs as an indicator of Bay health. In 2014, 68.5 million adult female crabs were estimated to be living in the Bay, compared with 147 million in 2013. According to a 2014 report from the Chesapeake Bay Stock Assessment Committee (CBSAC), the stock is depleted but overfishing is not occurring.
Blue crabs use underwater grass beds as nurseries and feeding grounds. A drop in underwater grass abundance—due to warming waters, irregular weather patterns and pollution—has been linked to the decline of blue crabs. Research has shown that grass beds protect crabs from predators and boost their growth rates. Research has also shown that denser grass beds hold more crabs, indicating both the quantity and quality of grass habitat can affect blue crab populations.
It is estimated that more than one-third of the nation’s blue crab catch comes from the Chesapeake Bay. Blue crabs—harvested as hard shell crabs, peeler crabs and soft shell crabs—are the highest-valued commercial fishery in the Bay, and bring in millions of dollars each year. Blue crabs also support a recreational fishery in the region.
Since the 1990s, there has been a dramatic decline in blue crab landings, as watermen expend the same amount of effort to catch fewer crabs. This could be linked to “recruitment overfishing,” which occurs when large removals of adults result in fewer juveniles being produced.
According to a 2014 report from the Chesapeake Bay Stock Assessment Committee (CBSAC), 40.7 million pounds of blue crabs were harvested from the Bay and its tributaries during the 2013 crabbing season. Recreational harvest was estimated to be 3.9 million pounds, while commercial harvests from Maryland, Virginia and those waters managed by the Potomac River Fisheries Commission (PRFC) were estimated to be 36.8 million pounds. The total harvest was the lowest seen this century and well below the maximum number of blue crabs that can be taken from the Bay.
Because recreational and commercial harvests affect the blue crab population, CBSAC has named improving the harvest data a top research need.
Debate has grown over the effect of predation on blue crab abundance. Striped bass, Atlantic croaker, red drum and other fish feed on juvenile blue crabs, and a change in these fish species’ populations could affect the abundance of blue crab “recruits,” or those crabs that are less than one year old.
Water quality improvements, underwater grass restoration and proper harvest management will help protect blue crab populations and maintain the resource into the future.
Blue crabs are managed as a single species, using minimum catch size and seasonal harvest limits to meet target levels of fishing pressure. The annual winter dredge survey helps scientists determine whether the target blue crab harvest level has been met or exceeded. Under this strategy, target fishing pressure is set to a level that should allow for increased blue crab abundance over time.
The Chesapeake Bay Program developed its first Chesapeake Bay Blue Crab Fishery Management Plan in 1989 to promote collaboration among the three jurisdictions that manage commercial crabbing in the watershed: Maryland, Virginia and the Potomac River Fisheries Commission (PRFC). The Bay Program’s Chesapeake Bay Stock Assessment Committee (CBSAC) has continued to provide scientific advice to fisheries managers, and publishes a Blue Crab Advisory Report each year that offers advice on harvest regulations.
In response to prolonged low blue crab abundance, CBSAC recommended new management actions in 2011, including sex-specific management and a target abundance of 215 adult female blue crabs in the Bay.
For Chesapeake Bay restoration to be a success, we all must do our part. Our everyday actions can have a big impact on the Bay. By making simple changes in our lives, each one of us can take part in restoring the Bay and its rivers for future generations to enjoy.
To protect blue crabs in the Bay watershed, consider protecting bay grasses. Boaters should follow posted speed limits and no-wake laws to avoid harming bay grass beds. Boaters can also steer clear of bay grasses growing in shallow waters.
Biodegradable escape panels could solve the region's ghost fishing problem.
By connecting chefs with seafood, the state agency emphasizes the importance of buying local.
Protecting females could rebuild the blue crab population.
The long, cold winter killed an estimated 28 percent of adult crabs in Maryland waters.
New research suggests higher-quality grass habitat could boost Chesapeake Bay blue crab populations.
The abundance of spawning-age female blue crabs in the Chesapeake Bay decreased to 68.5 million in 2014, compared with 147 million in 2013. This number is below both the 215 million target abundance and the 70 million threshold, which means spawning-age female crabs are currently in a depleted state.
Based on the results of the 2013 winter dredge survey and estimates of the 2013 Bay-wide harvest, the Chesapeake Bay spawning-age female blue crab population is in a depleted state, although harvest continued at sustainable levels. Harvest was estimated at 23 percent, just below the target (25.5 percent) and well below the maximum number that can be taken (34 percent).
Why are blue crabs important to the Chesapeake Bay? Bruce Vogt from the National Oceanic and Atmospheric Administration (NOAA) explains the iconic crustacean’s economic, ecologic and gastronomic value. Learn more about blue crabs in the Chesapeake Bay Program’s online Field Guide.
Produced by Matt Rath
Music: “A Moment of Jazz” by Ancelin
April 2013: The Chesapeake Bay winter dredge survey is an annual count of the Bay’s blue crab population, and a critical component of blue crab management. The information gathered on abundance, young-of-the-year and spawning stock—those crabs that will mature enough to reproduce during the upcoming year—allows fisheries managers to set commercial and recreational harvest limits for the season ahead.
Closed captions: http://www.youtube.com/watch?v=28mvEE7ydXA
Produced by Steve Droter
Music: “Elle Aime Ca” by Löhstana David
Publication date: December 09, 2003 | Type of document: Adoption Statement | Download: Electronic Version
The adoption statement was to implement the management strategies and actions recommended by this amendment to protect blue crab spawning potential, reduce exploitation, increase our biological understanding of blue crabs through…
Publication date: May 01, 1998 | Type of document: Management Plan
Incorporates new information from the first Baywide stock assessment and recommends additional management strategies. Plan recommendations to protect the health of the blue crab stock which has the highest monetary value of any Bay…
Publication date: June 04, 1997 | Type of document: Adoption Statement
The 1997 Chesapeake Bay Blue Crab Fishery Management Plan is a guide to conserving and protecting the blue crab resource for long-term ecological, economic and social benefits
Publication date: June 01, 1997 | Type of document: Management Plan
The 1997 Chesapeake Bay Blue Crab Fishery Management Plan incorporates new information and management strategies into the 1989 fishery management plan.
Publication date: October 01, 1995 | Type of document: Management Plan | Download: Electronic Version
As part of the process of establishing accountability and tracking the implementation of management actions, each fishery management plan (FMP) is annually reviewed and updated. This report reviews the progress of management plans during…