Appearance
- Brilliant blue color on front claws (tips are red in females); olive or blueish-green carapace (shell)
- Have one pair of claws, three pairs of walking legs, and one pair of legs shaped like paddles for swimming
- Juveniles have bright red-orange at claw elbow joints
- Nine lateral spines behind each eye, last pair ending in sharp spines
- Four low, blunt spines between eye sockets
Have an “apron” that covers their abdomen (male aprons are long and thin; female aprons are wide and either triangular or “U” shaped when sexually mature)
Similar Species
Other swimming crabs.
Size
Up to 9 inches in carapace width (from spine to spine across width of carapace).
Habitat
Seagrass beds and other submerged aquatic vegetation areas are important nursery habitats for juvenile blue crabs, while adults are common in a variety of fresh, brackish, and marine habitats.
Behavior
Feed on fish, mollusks, crustaceans, aquatic vegetation, and detritus. They will also feed on other soft shelled blue crab.
Blue crabs molt (shed their hard shell or “exoskeleton”) as they grow leaving a softer shell underneath that will harden within 48 hours. Molting rate increases during warmer months and decreases in the winter months when their activity slows down.
Reproduction
Spawn from March through December on Florida’s Gulf coast and year-round on Florida’s Atlantic coast with most spawning occurring winter through spring and late summer.
Mature males molt and mate with multiple females over their lifespan, while each female only mates once after the final molt into her mature form.
After mating in the upper reaches of estuaries, females leave the estuary in search of higher salinity waters, moving out to the mouth of the estuary or nearshore coastal waters to spawn.
Additional Information
Typical life span for a female is 1-2 years and a male is 1-3 years. However, some tagging studies have found crabs 5-8 years old.
The blue crab fishery is in the top five most valuable fisheries in Florida. They are commercially and recreationally fished.