Blue Crab

• Blue crabs generally live for 3 or 4 years.
• They reach maturity in 12 to 18 months. Growth rates are affected by water temperature—they grow more quickly in warmer water. In the Gulf of Mexico, crabs may reach maturity within a year. But in the Chesapeake Bay, it may take 18 months.
• Crabs molt—they shed their hard shell—as they grow. Because they lose hard parts during the molting process, it can be difficult to determine the age of a crab. Males molt multiple times during their lives. Females molt once, just before they are ready to mate.
• Blue crabs can grow to about 9 inches across (from tip to tip) their hard shell (carapace). However, they are usually harvested before they reach that size.
• While a blue crab usually weighs about ⅓ pound, the edible portion is much lower. The largest blue crab caught in the Chesapeake Bay weighed 1.1 pounds and was 10.72 inches (tip to tip across the carapace).
• Blue crabs eat almost anything, including clams, oysters, mussels, smaller crustaceans, freshly dead fish, plant and animal detritus—and smaller and soft-shelled blue crabs.
• Crabs are eaten by large fish, some fish-eating birds (like great blue herons), and sea turtles.
• To mate, a male crab cradles a female crab in a pose known as a “doubler” for a few days before the female’s terminal molt. They stay with her after mating until her shell hardens and to ensure another male doesn’t mate with her.
• In the Chesapeake Bay, blue crabs mate and spawn from spring to fall. Females migrate to the mouth of the Bay to spawn and can produce between 750,000 and 3,200,000 eggs per brood.
• Eggs hatch into larvae and go through a series of molts in high-salinity coastal waters and then migrate back into the Bay.

Where They Live

• The blue crab native range is along the Atlantic Coast of the Americas from Nova Scotia to Argentina, including the Gulf of Mexico.
• Within the Chesapeake Bay, male crabs tend to prefer the fresher waters of Maryland and the Bay’s upper tributaries, while females like the saltier waters in the main part of the Bay and in Virginia, closer to the ocean.
• The blue crab uses multiple habitats in the Chesapeake Bay throughout its life. Blue crab habitats include underwater grasses and oyster reefs, and they range from shallow, brackish waters to deeper, saltier waters.
• Blue crab distribution varies with age, sex, and season. They tend to be abundant in shallow-water areas during warm weather. As the water temperature drops each year, they burrow into sediment in the deeper parts of the Bay for the winter.
• Blue crabs are bottom-dwellers that use beds of submerged aquatic grasses as sources of food, nursery habitat for young, and shelter during mating and molting.