What Are the Threats to Chesapeake Bay Blue Crabs? It is likely that the loss of grasses is contributing to the blue crab's decline, along with water quality challenges and predation by invasive blue catfish.įisheries regulators and scientists must work quickly to identify the key ecosystem factors influencing blue crab recruitment and survival so they can be mitigated to ensure a healthy blue crab population in the future. The survey follows two consecutive years of declines in the coverage of underwater grasses, one of the most important habitats for blue crabs in the Chesapeake Bay. The extremely low estimate of the population in 2022 highlights the need to continue to protect spawning femailes and to consider precautionary measures to protect juveniles so they can grow to maturity and spawn. The blue crab population fluctuates annually based on a variety of factors, including reproductive success, weather, predation, and harvest. A comprehensive review of those results is completed annually by the Chesapeake Bay Stock Assessment Committee and released in early July. The survey is usually conducted December through March, and preliminary results are released around late April or May. This is one of the most comprehensive surveys of any species in the Bay, dating back more than 30 years to 1988. In 2022, the annual winter dredge survey showed a drop in blue crab population for the third consecutive year, dropping from an estimated 282 million to 227 million, the lowest in the survey's 33-year history.Įach winter, Maryland and Virginia partner on the scientific dredge survey, which produces an estimate of the number of blue crabs in the Chesapeake Bay and its tributaries. And, yes, the tales of cannibalism are true- blue crabs will eat other blue crabs. In fact, cobia are such voracious predators of blue crabs they are sometimes referred to as “crabeaters.”. Some of the more common Bay species that eat blue crabs include red drum, croaker, blue catfish and cobia.
Eventually, many crabs are then preyed upon by larger fish and birds. As they grow older, crabs feed upon a variety of smaller bivalves that live on the Bay floor. As larvae they are preyed upon by numerous filter-feeders, such as menhaden. Blue crabs serve many important roles in the Bay food web. Humans aren’t alone in our love of crabs. Picking steamed crabs has reached the level of an artform in many Chesapeake Bay communities, where they are often enjoyed for summer holidays and at family gatherings, and crab cakes are a staple of both restaurants and home cooking. Moreover, crabs continue to hold great cultural significance in the watershed. In Virginia, the commercial harvest value has ranged from $22 million to $38 million annually. In Maryland alone, commercial landings of blue crab have topped $45 million in dockside value annually for the past decade-far more than oysters and striped bass combined. Why Are Blue Crabs Important to the Chesapeake Bay?īlue crabs support one of the Bay’s most valuable commercial fisheries and a large recreational fishery. It takes a year to 18 months for a crab to reach maturity. The tiny blue crab larvae begin their lives in the ocean, growing and molting several times before they return to the Bay. Once they have mated, female crabs migrate to the saltier waters at the mouth of the Bay to spawn. Mating often occurs in shallower waters that support underwater grass beds. They are most active from spring through fall, but commonly burrow into the Bay’s bottom sediments during winter to wait out the cold. These grass beds form a crucial habitat that provides food, shelter, and protection when crabs are young and when they mate and molt (shed their shell).ĭepending on the time of year, blue crabs can be found in different parts of the Bay. They eat a range of foods including mussels, oysters, small crustaceans, and decaying plant and animal matter, and they are often found in the Bay’s underwater grass beds. They are found in coastal waters along the Atlantic Coast and in the Gulf of Mexico in the United States, although their range stretches as far south as Argentina in South America.īlue crabs have bright blue claws and four pairs of legs-the rearmost of which have paddle-like ‘fins’ that allow them to swim throughout the water column. Known as the "beautiful swimmer," blue crabs, Callinectes sapidus, are the most iconic Chesapeake Bay species.
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