For more than a hundred years, the blue crab has been a mainstay of fishermen. Blue crabs are widely distributed. Breeding populations extend from the Atlantic and Gulf coasts of Florida to Long Island. They also withstand extreme changes in salinity - from seawater to nearly fresh water. In areas where fresh water contains high levels of calcium, the blue crab may even extend into the freshwater region of the estuary.
Blue crabs eat a wide variety of plants and animals.
Juvenile crabs commonly prey on small bivalves, crustaceans, and polychaete worms. Larger crabs also feed on fish. Crabs of any size consume freshly dead material, but they are not true scavengers because they do not ingest fouled or decaying material. Fertilization includes copulation, which occurs only once in the life of each female, during the few hour period following the female's terminal or puberty molt. During this doubling period, the crabs seek sheltered areas secure from predators.