Photo: Underwater view of a blue crab

Overfishing and deterioration of their habitat has stressed blue crab populations throughout much of their range.

Photograph by George Grall

Map

Map: Blue crab range

Blue Crab Range

Audio

Fast Facts

Type:
Invertebrate
Diet:
Omnivore
Average life span in the wild:
1 to 3 years
Size:
4 in (10.2 cm) long; 9 in (23 cm) wide
Weight:
1 to 2 lbs (0.45 to 0.9 kg)
Group name:
Cast
Did you know?
Female blue crabs mate only once in their lives.
Size relative to a tea cup:
Illustration: Blue crab compared with tea cup

The blue crab is so named because of its sapphire-tinted claws. Its shell, or carapace, is actually a mottled brownish color, and mature females have red highlights on the tips of their pincers.

Prized by humans for their sweet, tender meat, these wide-ranging, ten-legged crustaceans are among the most heavily harvested creatures on the planet. Their scientific name, Callinectes sapidus, means "savory beautiful swimmer."

Blue crabs are found in brackish coastal lagoons and estuaries from Nova Scotia, through the Gulf of Mexico, and as far south as Uruguay. Close relatives of the shrimp and lobster, these bottom-dwelling omnivores have a prickly disposition and are quick to use their sharp front pincers. Large males can reach 9 inches (23 centimeters) in shell width.

They feed on almost anything they can get hold of, including mussels, snails, fish, plants, and even carrion and smaller blue crabs. They are also excellent swimmers, with specially adapted hind appendages shaped like paddles.

Blue crabs are extremely sensitive to environmental and habitat changes, and many populations, particularly in the Chesapeake Bay in the eastern United States, have experienced severe declines. Blue crabs also play a key role in managing the populations of the animals they prey on, and constant overharvesting has had wide-ranging negative effects on the ecosystems they inhabit. For this reason, comprehensive management schemes are in place in several parts of the blue crab's range.

Invertebrate Features

  • Photo: Organ pipe coral

    Coral

    It's reef madness in this colorful gallery of coral formations.

  • Photo: Cluster of orange cup coral

    Photo Gallery: Coral Reefs

    About 80 percent of all life on Earth is found in the oceans, which cover 71 percent of the planet's surface. Take a look at how colorful life under the sea can be.

  • Photo: A lobster and crab on the seafloor

    Lobster

    Learn more about these popular crustaceans that some think of only as a meal. Find out the sizes that these sea creatures are capable of attaining.

  • Photo: Sea cucumber

    Sea Cucumber

    Learn how these amazing echinoderms deter predators by snaring them with sticky threads and even hurling their internal organs about.

Animals

The Innovators Project

See more innovators »

From the Magazine

  1. Photo: Two adult preen, Ireland

    Gannets Pictures

    Champion divers but clumsy landers, doting parents but hostile neighbors—northern gannets abound in contradictions.

  2. Photo: Silent Ural owl

    Estonia's Ural Owls

    Photographer Sven Začek provides an intimate view of this large raptor.